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Tuesday, October 4, 2011

printsilkscreen: how to print Silk-screen manually

printsilkscreen: how to print Silk-screen manually: how to print Silk-screen manually INTRODUCTION There are 5 basic steps to photo screen making and printing: 1. Artwork Preparation...

SCREEN MAKING

SCREEN MAKING


IMAGE HARD TO WASH OUT




WHITE SPOTS APPEAR WHEN COATING SCREEN



PHOTO EMULSION WASH AWAY





PHOTO EMULSION PEELING EXCESS PINHOLES
May  be due  to May  be due  to May  be due  to



May  be due  to

May  be due  to
1. Overexposure during exposing. Change
Time!
2. Artwork not opaque enough. Darken It!

Oil from  skin  left on screen. Remove photo emulsion, wash the screen thoroughly and start  again!

1. Too  little  sensitizer. Measure Again!
2. Short exposure time. Change time!
3. Improper distance. Change Distance!
4. Water too warm or pressure too strong.
Use  cooler water or change pressure!

Emulsion too thickly applied. Apply less!

Emulsion too sparsely applied. Apply more!




When water-based ink dries in screen – use spray bottle with  water and  spray directly on the screen. Just  a small amount will  open it up. Certain inks  will  not wash out if they  dry in the screen, so be careful not to leave the screen inked without printing, or the screen may be ruined. CrownTM Retarder works well  to slow  down drying time  and  keep  screen open longer while printing.

Spray inside of screen only. If the outside gets  smeared you  must wash the entire outside or print until  the smear disappears.

Oil based inks  are more flexible in terms of drying time. Use  ink thinner or screen wash on a paper towel and  apply directly to inside of the screen where the ink has  dried. Do not rub  the outside of the screen. If the outside is smeared you  must clean the entire outside or keep  printing until  the smear disappears.

Always test  print before production runs.

If you  have  problems that  you  cannot solve and  your  local  dealer cannot help  you,  do not hesitate to call  our factory.


PRINTING DOUBLE IMPRESSIONS

PRINTING

DOUBLE IMPRESSIONS




LIGHT IMPRESSIONS



IMAGE LIGHT ON  ONE SIDE, DARK ON  OTHER SIDE

BLEED IN PRINT OR HAZY IMAGE



INK  DRIES IN SCREEN
May  be due  to




May  be due  to May  be due  to May  be due  to

May  be due  to
Moving screen while printing. Secure screen or have  someone hold  screen while you print!

Insufficient pressure. Press harder! Hold squeegee on more of an angle!

Unequal pressure on squeegee. Press harder on the light  side!

Too  much pressure on flood stroke or Too much pressure when printing. Reduce pressure!

1. Too  much time  between prints. Hurry up!
2. Fine  lines  in artwork. Add  retarder to ink!
3. Incorrect mesh. Change mesh! Print faster!



SCREEN MAKING


IMAGE HARD TO WASH OUT




WHITE SPOTS APPEAR WHEN COATING SCREEN



PHOTO EMULSION WASH AWAY





PHOTO EMULSION PEELING EXCESS PINHOLES
May  be due  to May  be due  to May  be due  to



May  be due  to

May  be due  to
1. Overexposure during exposing. Change
Time!
2. Artwork not opaque enough. Darken It!

Oil from  skin  left on screen. Remove photo emulsion, wash the screen thoroughly and start  again!

1. Too  little  sensitizer. Measure Again!
2. Short exposure time. Change time!
3. Improper distance. Change Distance!
4. Water too warm or pressure too strong.
Use  cooler water or change pressure!

Emulsion too thickly applied. Apply less!

Emulsion too sparsely applied. Apply more!




When water-based ink dries in screen – use spray bottle with  water and  spray directly on the screen. Just  a small amount will  open it up. Certain inks  will  not wash out if they  dry in the screen, so be careful not to leave the screen inked without printing, or the screen may be ruined. CrownTM Retarder works well  to slow  down drying time  and  keep  screen open longer while printing.

Spray inside of screen only. If the outside gets  smeared you  must wash the entire outside or print until  the smear disappears.

Oil based inks  are more flexible in terms of drying time. Use  ink thinner or screen wash on a paper towel and  apply directly to inside of the screen where the ink has  dried. Do not rub  the outside of the screen. If the outside is smeared you  must clean the entire outside or keep  printing until  the smear disappears.

Always test  print before production runs.

If you  have  problems that  you  cannot solve and  your  local  dealer cannot help  you,  do not hesitate to call  our factory.




POSTSCRIPT: ABOUT FABRICS

Choose it or lose  it!

The  key  to good  screen making is the proper choice of screen fabric or mesh. If you  choose the wrong fabric, you  may  lose  your  image. Choose screen fabrics according to:

The  delicacy of lines  desired in the artwork. Fine  lines and  broad lines  require different fabrics.
The  type  of printing ink used. Since inks  differ in viscosity, check the ink can label  for suggested mesh size.
The  substrate or object being printed.

Screen Fabrics consist of woven threads. These threads act as strainers for the ink. Tighter weaves allow les ink to pass  through the mesh and  on to the substrate. More open  weaves allow more ink to pass  through the mesh and  on to the substrate.

Fabric thickness, however, also  affects ink deposit. The  thickness of the fabric varies according to:

Mesh count: The  number of threads per inch. Thread diameter.

There are two  categories of fabric construction or thickness: Multifilament and
Monofilament.
Multifilament Weaves   

Multifilament weaves are made up of multiple stranded filaments twisted to form  a single thread (See  Diagram). The  surface is rough, less  uniform and  the fabric is thicker. Photo emulsion adheres very  nicely as do hand  cut stencils. Thus  multifilaments are suited for heavy ink deposits, offer  excellent adherence for both  knife cut stencils and  photo process stencils. Also, multifilaments are usually readily available.

Most commonly used  multifilaments are made of polyester. The  polyester fabric offers easy removal of the photo stencil. Although silk  is also  a multifilament, it is not as commonly used
since the photo emulsion cannot be removed without destroying the silk  fabric. The  chemicals used  to remove the photo stencil will  disintegrate silk,  but polyester is not attacked by such chemicals making it more suitable for photo stencils.

The  wide  thread thickness of multifilament fabrics create a lower open  area  in finer  meshes which make it difficult to print  fine  detail. However, multifilaments work very  well  on textiles where a heavier deposit of ink is needed.

Multifilaments range from  6xx  to 25xx. The  higher the number, the finer  the mesh.










Monofilament Weaves




Monofilament weaves are made up of single-strand threads. The  surface is smoother because the single strands can be woven closer than  multifilament weaves. Monofilaments are much more uniform than  multifilaments. For this  reason, hand  cut stencils do not adhere well  to monofilament fabrics. Photo stencils, however, work well  with  monofilaments. Because the threads can be made with  a thin  diameter, monofilament fabrics can be woven in very  fine  meshes and  still  retain adequate open  area  for easy  ink passage.

Monofilaments also  have  very  good  abrasion resistance and  are highly stable. This  is needed for fine  line  quality printing. However, considerably less  ink will  be deposited. When printing halftones this  factor is very  important. In selecting screen fabrics for halftone printing, multiply the line  dot by three  to obtain the minimum fabric mesh to be used. Conversely, to determine the minimum dot size  that  can be printed with  a specific fabric mesh, divide the mesh size  by three. However, experimentation with  this  formula should be done  when working with higher line  dot sizes.

Monofilament weaves can range from  16 to 470  mesh count. Usually, meshes over  355  are used  with  ultra  violet ink.  Because these inks  do not dry there  is no need  to worry about clogging up the stencil.

Note: Colored fabrics are recommended when using monofilaments because longer exposure times will  still  yield  high  quality stencils. Since light  tends to travel quicker along white fabrics, it may  creep behind your  artwork and  affect the photo emulsion. If the artwork lines  are thin  or if exposure time  is long, the photo emulsion may  become overexposed.

Polyester:    Excellent all-purpose fabric – for multifilament and  monofilament weaves.

Nylon:    High  stretch factor – for printing irregularly shaped substrates.

Wire  Mesh:    Extremely stable fabric – low  stretch factor – heavy deposit of ink –
print  circuits, ceramics, and  garments.

Silk:     Oldest known fabric used  in screen printing – rarely used  due  to lack  of availability, expense, and  vulnerability to chemicals.

PRINTING!!!!

PRINTING
Taping the Screen

Your screen developed well,  it is now  dry and  you  want  to start  printing. Before you  start  to print, the screen must  be taped to prevent ink seepage through the edges where the fabric mesh meets the frame. Since tapes vary  in adherence strength and  are affected by the ink chemistry, it is important to choose a tape  that  works with  the ink you  are using.

Use  plastic tape  when printing with  water based ink.

Use  paper tape  when printing with  oil based ink.

Use  masking tape  when printing with  oil or water based inks  but it is not as durable as paper or plastic tape  and  would work only  for short  runs.

Tape Width should be 2” or more. Measuring the tape  length is an important step  in making a neat  and  professional-like screen. When taping the inside of the screen, measure each length from  corner to corner with  a slight overlap. For example: If your  screen is 8” x 10”  measure two  pieces 8 1/2”  and  two  pieces 10 1/2”  for the inside of the screen. Screens are always sized by the inside dimensions. The  outside dimensions will  be somewhat larger and  it is always best  to measure what  they  are and  cut eh exact size.

After you  have  measured and  cut the correct size  length of tape,  adhere half  of the tape  to the mesh and  half  of the tape  along the wood frame (see  diagram). Repeat this  on the outside of the frame, being sure  to cover the entire perimeter on both  the outside and  the inside of the frame.

If you  made the multicolor screens, the images made by the registration pins  can be taped over. If the image is too close to the artwork to be taped, use blockout.







Off Contact and  On Contact

There are two  techniques of printing, namely off contact and  on contact. On contact is defined as follows: When the screen is in the down position or the print  position, the screen fabric is resting on the surface of the item  to be printed. This  needs no special preparation. Off  contact is defined as follows: When the screen is in the down position the screen fabric is prevented from touching the surface of the item  to be printed by a piece of cardboard or other material that  is
taped to the outside of the screen.

Off  contact is usually used  when printing on a nonabsorbent surface such  as paper. Off contact keeps the screen fabric from  sticking to the paper after  a print  is made. When the screen is in the down or print  position and  not touching the surface of the item  to be printed, the squeegee pressure will  push  the screen fabric down. The  off contact will  cause the fabric to spring away quickly from  the paper thus  eliminating a static cling  (See  Diagram). When the print  stroke is complete, the screen fabric should not be touching the print  surface. Prepare off contact by taping a piece of cardboard, about 1/16” to 1/4”,  depending upon  the size  of the screen, to the outside of the wood frame. Experiment to gain  the maximum fabric spring from  the paper without creating too much off contact.




Hinging the Screen



Some screens come with  hinges that  are attached to a separate base. These screen printing units  fit neatly together. Simply screw the hinges to the back  of the base  and  into  the screen, as shown in the Diagram.








For “ T” shirt  printing with  a screen that  is hinged to a base, it is important to make the following variation in hinging. Place a piece of cardboard, the same width as the cardboard you  will  use to insert inside the “T”  shirt, under the hinges that  are attached to the base. This  will  elevate the hinges so the screen hinges will  meet  the base  hinges when the “ T” shirt  is under the screen. By meeting the height of the cardboard that  is inserted in the shirt  the balance in the printing unit  is reestablished.







“ T” Shirt  Printing requires a platen which is inserted into  the shirt  to prevent ink from going through the fabric and  penetrating the back  of the shirt. This  can be made from  cardboard. Cut  a rectangle that  is wide  enough to stretch the shirt  tightly so there  are no wrinkles in the printing area.  It is very  important to keep  the print  area  smooth when garment printing. This cardboard rectangle is removed after  each  print  is made, and  is placed inside the next  shirt  to be printed.



Constructing a Platen For  Monocolor Printing




A more professional platen can be made with  3/4”  plywood with  a Birch or Formica top (See  diagram). Have a lumber yard  cut a 15”  square with  rounded corners so it is easy  to slide  the “T”  Shirt  on. Bolt  a 2x4  to the bottom of the platen. It should be long enough to extend past  the platen so the shirt  can drape, and  so the 2x4  can also be bolted to a table  or a waist-high stationary object. Attach another piece of wood across the top so there  will  be room to screw hinge clamps. Approximately 2” past  the back  of the platen, attach a piece of wood the same thickness as the platen. It should be as wide  as the platen, and  deep  enough to screw on hinge clamps (approximately


4” x 15”).




Constructing a Platen For  Multicolor Printing




The  basic construction remains the same as the monocolor platen;
however, instead of using hinge clamps to hold  the screen, the 3 point contact bar system is used. Since the platen
and  the screen sit on the 2x4,  the contact bar must  be thicker in this  case so the eyebolts can butt  up against it. To calculate the thickness of this  bar, simply add  together the thickness of the screen wood and  the thickness of the platen.








Constructing a Table For  Monocolor or Multicolor Yardage Printing

To print  yards of fabric with  specific pattern repeats a long  table  must  be available or constructed. It must  be wide  enough to hold  the screen and  the contact bar. The  contact bar must
be screwed or taped securely to the back  of the table. On top for the contact bar,  attach bolts  which will  serve as register stops for the pattern repeat and  for multicolor registration. These bolts
should be placed at intervals of the desired pattern repeat. The  thickness of the contact bar must  be equal to the thickness of the screen so the L-angle can lock  against the bolt  and  the eye-bolts can butt  against the contact bar (See  Diagram).



Page 20




Preparing Registration

Registering the Screen for Monocolor Printing on Paper




When printing one  color on paper, you can use a screen with  hinges attached to the base or you  can use hinge clamps. When the screen and  base  are purchased as a unit  and  the hinges are attached to both  parts, you  cannot move the screen so the stock must  move to be centered. When printing an edition of paper prints, it is important to have  registration guides that  enable you  to print  the same image on different pieces of paper in approximately the same position. Once you  find  the place on the paper where you want  the image to print, make an L shape and  an inverted L shape in each  corner of the paper on the printing base. Tape  will  work nicely as a
paper guide. Now  you  can print  repeat images on different pieces of paper in approximately the same position on each  separate piece of paper. Place each  piece of paper within the L guides to print  in consistent registration.

If you  choose to use hinge clamps you  will  need  to screw them  into  the printing table  or you  can use a C-clamp to hold  the back  of the hinge clamp to the table. Hinge clamps will  enable you  to move the screen vertically or horizontally but this  is not crucial for monocolor printing.

Registering the Screens for Multicolor Printing on Paper




When printing more than  one  color on paper, hinge clamps will  work better and  give  you  more flexibility since they  allow you  to move the screen horizontally and  vertically. Hinge clamps prevent the loss  of registration and  make it easier to print. Once tightened, hinge clamps lock  securely and  do not slip while printing.


To register the screens you  will  need  to center your  main  acetate or outline (let’s call  this the master) to the center of a piece of the stock you  are printing on. This  will  serve as a master for registering all the colors and  traps.

Place this  master sheet on the printing table  and  register the first  screen to it. Be sure  to
print  light  colors first  unless your  design calls  for an opaque light  color on a dark  ground. Check to see if the screen image lines  up with  the acetate or master image. Be sure  to leave no spaces between colors when they  are supposed to meet. This  is when the traps  you  made as artwork are necessary. Move the screen horizontally and  vertically to achieve the maximum overlay coverage.




Once you  register the screen to the artwork, make a paper guide by placing an L and  an inverted L on the printing base  where both  lower corners of the paper rest.  Now  you  can begin to print. Paper is printed wet  to dry so you  will  need  to wait  until  the first  color is dry before you print  the second color.

To print  the second color, place the master sheet within the guides. Now  line  the second screen up to the artwork, aligning the design so no spaces appear between the colors where they are supposed to meet. Make doubly sure  of the registration by placing a dry print  under the screen and  seeing if the image falls  in the right  place. If not,  make the necessary adjustments, tighten the hinge clamps and  print.




Before you  begin to print, tape your original drawing to the print base. Take your  first  screen, place it loosely in the hinge clamps and  move the screen so the image lines  up with  the portion of your original design that  is to be printed. Now  tighten the hinge clamps. Replace your  original drawing with  the stock that is to be printed. Always register stock by placing L and  inverted L in lower corners on the print base. This  is to ensure that each  piece of print stock sits in the exact same place for all colors. If you  are not careful enough to place each  piece of
stock within these guides the successive colors will  not line  up properly and  they will  be out of registration.







Registering the Screen for Monocolor Printing on Textiles






When printing one  color on a “T”  shirt, simply center the shirt  under the image and  tighten the hinge clamps. If you  are using a stationary screen and  base, center the shirt  under the screen. When printing this  way be sure  the entire image prints before lifting the screen because the shirt  will  shift  on the cardboard. Make test prints to get the feel  of laying down the ink before using your  good  stock.

Always use an adhesive when printing on textiles to prevent movement of the garment when you  lift the screen. CrownTM Table Adhesive works very  well  and does  not stick  to the garment. Simply apply a few  drops to the printing area  and  allow to dry to a tacky finish. Then place the textile down without creating any  wrinkles. Wrinkles will  stop  the ink from  printing properly and cause uneven deposits.




Registering the Screens for Multicolor Printing on Textiles

If you  are using the homemade Eye  Bolt  and  L-Angle system, you  will  need  help  printing. Since textiles must  be printed wet  to wet,  you  will  have  to remove each  screen and  replace it with the next  color screen. This  might be difficult for one  person to do without having the ink dry in the screen or without having to lay the screen down.

If you  are printing alone you  must  create a setup area  where each  screen would be easily accessible without wasting time  and  energy looking for screens. A bridge table  set up next  to your printing area  where the screens can be propped up between prints will  do fine.

Have the shirts ready and  close by. Mounting adhesive is necessary to keep  the garment from  shifting while printing and  now  is the time  to apply it. You  can use a hair  dryer to speed up the drying time.

Since you  took  the time  to use the 3 point contact system to register the screens to the artwork when you  exposed the screens, they  should now  be in perfect registration for printing. In the diagram shown, the colors that  are going to print  are green for the leaves, red for the apple, and black for the overall outline. To determine your  print  rotation, start  by printing light  colors and work toward dark  colors. Of course careful examination of your  art work will  determine which colors overlay or print  over  each  other. In this  example, the green would print  first,  the red second and  the black third.






Slide the shirt  onto  the platen with  the collar towards you  and  smooth out any  wrinkles that  might appear. Take  your  first  screen, in this  case  the green leaves, and  check for placement on the garment before inking the screen. Note: The  screen must  make 3 point contact with the contact bar.  If you  need  to adjust the shirt  do so now.  If you  are ready to start  printing, pour  ink in the screen, make a flood stroke and  then  make a print  stroke. Usually, the print  stroke is made towards the printer; however with  the eye-bolt L-angle system the print  is made away from  the printer to prevent the squeegee from  pulling the screen away from  the contact bar.  If the screen is pulled away
from  the contact bar,  the print  will  be out of registration and  it could also  create a blurred image.



After the print  is completed, lift the screen gently and make a flood stroke. Without putting the screen down on the shirt  again, check the print. If the image does  not look complete put the screen in the 3 point contact position and  make another print  stroke, being sure  to print  away from yourself. If the print  looks complete, prop  the screen on the work table  so the outside of the screen does  not touch anything.



Now  you  are ready for screen number two.  In this example, screen two  is the red apple. Repeat the process exactly the way  you  printed screen number one.  Take  the second screen and  place it in the print  position over  the first print, in the 3 point contact position. Check to see if the
first  print  aligns with  the second screen. If the screen needs minor adjustments, simply turn  the eye-bolts in or out to fine  tune  the image. If the first  print  aligns with  the second screen then  ink the screen and  print  away from  yourself exactly as you  did with  the first  screen.



Finally, repeat the same process with  the third screen, which in this  case  is the black outline. Be sure  this last outline fully  covers the image. Here  is where the traps become relevant. The  last screen should also  pull  the print together and  reward you  for taking the time  to properly complete each  step.




It is not recommended to print  more than  three  colors at a time  with  this  3 point contact system, because the time  between prints could cause the ink to dry in the screen.

Register the Screens for Monocolor or Multicolor Yardage Printing

When using the 3 point system for yardage printing, you  have  a choice of printing wet-to- wet  or wet-to-dry. For instance, if the table  is long  enough you  can print  one  color, making all the prints along the line.  You  can clean the screens and  allow the prints to dry and  then  follow with  the second and  third  screens, waiting between colors. The  technique is always away from  yourself.

The  number of repeats of the pattern can be controlled by the distance between the bolts  on the contact bar.  It is quite  common for professional screen printing shops using this  technique to work in teams. This  technique is still  widely used  today. For example, three  colors might be printed by three  persons following each  other down the line,  printing a separate color. Note: If the repeated images are too close to each  other the bottom of the screen may  interfere with  the previous print.

Printing Techniques

Now  you  are ready to print. Actually the printing stage is the easiest of all the work you have  done  and  the most  time  consuming to perfect. Using a narrow blade spatula, scoop some ink onto  the screen just  below the image area.  Raise the screen slightly and  spread the ink over  the entire image area  with  your  squeegee. Press lightly; the object is to cover the image with  ink, not to push the ink through the screen. This  is called the flood stroke.








After you  have  flooded the screen with  ink,  lower the screen onto  the textile or paper and run the squeegee down the screen. Apply more pressure; the object is to push the ink through the screen and  onto  the stock. This  is called the print stroke. Paper printing will  require less pressure than  textile printing because paper is a nonabsorbent surface. Angle the squeegee with  the handle toward your  body. The  squeegee should be comfortable in your  hands. Always use two hands for uniform printing.







Lift  the screen slightly and  push  the ink back  up to the top or flood stroke. Remember to press lightly when flood stroking. Do not move the stock until  you  have  checked the print. If the image looks complete, remove the stock. If the image does  not look  complete you  may  want  to overprint. When overprinting do not remove or move the stock, simply lower the screen and  try again. Always remember to flood stroke.

It takes time  to develop a good  printing technique. Observation and  practice will  turn  you into  a good  printer, so print, print, print!

Always test  print before production runs. Use  scrap paper or textile to get the screen going before you  use your  good  stock.

Cleanup.

Scoop all ink out of the screen with  cut cardboard pieces. Return unused ink to the container; never waste ink!  Remove the screen from  the hinges or hinge clamps. Clean the screen according to the instructions on the ink can label. For example, water based inks  require water cleanup with  a spray hose. Oil based inks  require solvent cleanup. For solvent cleanup, place the screen on a stack of newspapers and  pour  some screen wash inside the screen. Wash it around with a rag or paper towel. Remove the newspapers and  repeat the process until  the image area  is clear. The  image area  is clean when light  shines through when you  hold  the screen up to the light.




TROUBLESHOOTING

THE  FOLLOWING PROBLEMS CAN OCCUR DURING SCREEN MAKING AND PRINTING AND WHAT YOU CAN DO ABOUT THEM


how EXPOSING THE SCREEN

EXPOSING THE SCREEN

Exposing Monocolor Screens for Printing on Paper or Textile

After the screen is thoroughly dry,  it is ready for exposure. For home use,  one  of the easiest ways to expose a screen is to have  the bulb  or light  source placed under the screen and  beamed upward toward the artwork (See  diagram). What is needed is a tight  sandwich between the screen and  artwork. Place the artwork on the cleaned glass  and  center the screen on top of the artwork. Use a piece of black construction paper or something similar to cover the inside of the screen.
Now  place a book  on top of the paper. The  screen fabric and  the artwork are pressed against the glass  by the book  or similar weight. This  is to prevent the light  from  creeping to areas where it is not wanted, and  will  give  you  a sharply detailed screen. Please follow the order of the materials exactly as shown for best  results.






There is an important relationship between how  well  your  screen develops and:  (1) The time  of exposure; (2) The  bulb  wattage; (3) The  distance between the light  source and  the screen.

The  time  of exposure depends upon  bulb  wattage and  the distance between the light  source and  the screen. Screen sizes  8” x 10”  and  10”  x 14”,  placed 12”  away from  a 150W flood bulb, will cause exposure time  to vary  from  4 to 6 minutes. Screen size  12”  x 16”  may  need  increased distance from  the light  source to ensure full image exposure. This  increase in distance from  12”  to
20”  will  require longer exposure time. Try  exposing the screen about 6 to 8 minutes. According to the opacity and  line  quality of your  artwork, you  will  need  to experiment with  this  formula; however, the following is an approximate relationship. When using a 150W flood bulb, try exposing the screen for about 20 seconds per inch  distance between the screen and  light  source.
For screens larger than  14”  x 17”  this  formula may  not work. You  may  even  need  multiple bulbs to get an even  dispersing of light. Caution: Prolonged exposure to light  when shooting the screen may result in an overexposed screen which will  not wash out during development. Overexposure can also  burn  the stencil. If the light  is too close it may  expose the center only  and  not the outer edges.




Exposing Multicolor Screens for Printing on Paper








The  screens are registered by taping registration pins to the glass  that  you  are exposing the screens on, and placing your  artwork on the pins.  Center the screen over the artwork and  make an L shape and  an inverted L shape at the bottom corners of the screen with  tape.  Each successive color is then  placed on the registration pins, centered in the screen within the L guides, and  exposed (See  Diagram).























Exposing Multicolor Screens for Printing on Textiles.




If you  have  a professional “T”  shirt  printing machine, expose the screens the same as for printing on paper. If you  are using the homemade Eye-Bolt, L-Angle system the screens must  be prepared in a special way.  Each screen must  have  2 Eye-Bolts screwed halfway into  the top of the wood frame. Half  of the threads should be visible. This  will  give  you  room for adjustments when printing. Each  screen must  also  have  an L-Angle screwed on the frame at the top (See  Diagram).






Tape  a piece of wood the same thickness as the screen, on the exposure glass. Screw a bolt  into  the center of the wood (See  Diagram) so the L-Angle can lock  up against it. The  2 Eye-Bolts should butt  against the wood and  the L-Angle must  butt  against the bolt creating a 3 point contact (See  Diagram). Place the screen on the glass  in this  3 contact point position. Place your  artwork in the center of the screen and  tape the registration pins  down so all the following
acetates will  be in the same place. Now  expose the screen to the light  source. When exposure is complete, remove the first  acetate and  place the next  acetate on the registration pins.  Place the screen on the artwork
in the 3 contact point position as was  done  for the first screen. Expose the next  screen. Continue this  process until  all screens are exposed. With  this  3 point contact system, all the screens will  be exposed in registration and  this  will  make printing much easier for you.







Important Things to Remember

Minimum starting distance should be 12”  from artwork to light  source. Due  to different fabric meshes and  line  widths of artwork, you  may  have  to experiment with  this  formula; make modifications as necessary.

If you  do not use a bulb  holder, but  rather an ordinary household lamp, the light  will  be more diffuse, and  you  may  need  more exposure time.




DEVELOPING THE SCREEN



Work in a dim  or amber light.

Develop the screen immediately after exposure. After exposing the screen, the image is developed by washing the screen with  cool  water. Light to moderate pressure is best  and  can be obtained by using a shower or garden hose  with  a sprinkler nozzle. All opaque areas that  were  in your  artwork should wash out and  your  image will  become a direct stencil or part  of the screen. Remember: In the open areas where the photo emulsion does  not harden, the ink will  pass through the mesh, like  a strainer, and  onto  your  paper, textile or other substrate.








Prop  the screen up and  move the hose  from side  to side  or in a circular motion beginning with the outside of the screen. Turn  frequently and
wash out both  sides. When the image begins to wash out you  can turn  the regular lights back  on.









Hold  the screen up to the light  and  check to see if light  shines clearly and  evenly through the areas that  were  opaque. If so, then  all areas washed out;  if not then  gently wash again. Be careful, too much washing can soften the emulsion and  it may  begin to break away in areas that are necessary to define your  design.

If the screen washes out quickly and  begins to wash away it could be underexposed; you may  need  to increase the exposure time. If the areas that  were  opaqued will  not wash out,  the screen could be overexposed. In that  case  you  may  need  to reduce the exposure time  or make your artwork more opaque.

After your  screen is dry,  tiny  pinholes or starlike specks may  appear when you  hold  the screen up to the light. With  a paint  brush, dab  some excess sensitized photo emulsion onto  these pinholes. You  can also  pain  the emulsion in areas that  you  wish  to close or better define. Do not wash the screen after  you  have  touched up with  sensitized emulsion. Simply place the screen under and  ordinary lamp  or sunlight to dry.

Blockouts work best  for closing unwanted open  areas in the screen. With  blockouts you  can close certain areas in the screen, and  print; then  you  can remove the blockout, and  reverse the process, so the areas that  did not print  will  now  print, and  the areas that  did print  will  not print.



how to print Silk-screen manually

how to print Silk-screen manually

INTRODUCTION



There are 5 basic steps  to photo screen making and  printing:

1. Artwork Preparation
2. Coating the Screen
3. Exposing the Screen
4. Developing the Screen
5. Printing



This  manual will  guide you  through the 5 steps  with  graphic representations and descriptions. Before work is begun, however, you  will  need  to prepare the necessary materials for silk  screening.

Necessary Materials For  Silk  Screening

* Screen, 2” larger on each  side  than  artwork to be screened (Always coordinate mesh size  to  ink requirements)
* Squeegee, 1” smaller than  inside screen dimensions
* Ink (Choose according to printing surface and  desired qualities) Photo Emulsion and  Sensitizer
Tape  (see  TAPING THE SCREEN for type  you  need): Paper, Plastic or Masking
Newspapers
Household Bleach
Household Hydrogen Peroxide
Scrub Brush, Soft  Bristle
Bulb  – Preferably a 150 Watt  Flood Bulb
Measuring Cup
Old  Rags  or Towels (Paper or Cloth)
A Piece of Glass Large Enough to Support the Screen and Allow for Propping on
Both  Sides Without Interference With  the Light Source
Spatula – Approximately 1”
Cardboard – Pieces Cut  to About 3” x 6” (For  Ink Cleanup)
Opaque Marker, Technical Pen  (Use  Ink For Plastic Sheets), Graphic Arts  Tape, India Ink,  Ruby Film, and  Stencil Knife (see  ARTWORK PREPARATION for full description of choices)
For Multicolor Work Only, Registration Pins  and  a Standard 1/4”  diameter hole puncher
For Multicolor Textile Printing Only  – Eye  Bolts, L-Angles, wood for Contact Bar and  Platen (See  “T”   Shirt Platen)




ARTWORK PREPARATION



The  first  and  most  important step  in successful screen making is artwork preparation. In photo screen making and  screen printing all the steps  that  follow artwork preparation depend on accurate duplication of your  design. In order to render the exact image you  want  it is absolutely necessary for your  artwork to be opaque. Opaque artwork means you  cannot see light  through the areas of your  artwork that  you  want  to print. Hold  your  artwork up to the light  and  check this  to insure no light  shows through the areas you  darkened. It is very  helpful to check opacity on a light box.

The  opacity of your  artwork is crucial to obtaining a clean well  defined stencil. The
artwork you  create will  become part  of the screen and  this  is called a stencil. The  opaque materials you  use to create your  artwork will  stop  the light  from  getting to the photo emulsion, which will  be coated onto  the screen, and  when you  shoot the screen the light  will  not be able  to penetrate the opaque materials. If light  does  not get to the photo emulsion, it will  not harden in that  area.  When the screen is developed or washed out,  the parts  that  were  not exposed to light  will  wash out.  Later during printing, the ink will  pass  through these undeveloped or washed out areas in the screen and the ink will  print  the exact image of your  design.

Basically there  are many different materials that  can be used  to prepare artwork for a photo screen, however they  must  all be opaque mediums and  they  must  work on clear  acetate or clear polyester (plastic sheets). Materials such  as

India Ink
Red  Ruby Masking Ink
Ink  For Acetate Pressure-sensitive Lettering Dry  Transfer Lettering
Opaque Markers That Work On Any  Surface
Technical Pens Graphic Art Tapes Ruby Tape
Ruby or Amber Film Shading Film  Stencil Knife

Actually any  material that  will  filter  out ultra  violet light  will  work to create a photo screen because ultra  violet light  causes the photo emulsion to cross link  and  become a waterproof coating or stencil.




Creating Artwork.



Making Monocolor Artwork

To make artwork, simply tape  your  drawing down to the table  and  tape  a sheet of acetate over  it. Now  you  can trace  your  image with  any  of the opaque mediums mentioned. You  can also create directly on the acetate without tracing. If you  choose to make words, you  will  need  a grid sheet or piece of paper with  horizontal lines  that  are straight so your  lettering can be transferred to the plastic sheet in a uniform patter (See  Diagram). Burnish the transfer lettering directly onto  the acetate but be sure  to put clear  Scotch tape  over  it when you  are finished so the letters will  not
chip  or peel  while you  are handling or storing the sheet.




Making Multicolor Artwork

When making multicolor artwork, exact overlaying of colors is crucial to render a print  that will  not have  spaces between colors. This  is called registration of colors. Overlapping of colors is called trapping and  is crucial to good  registration. Good traps  mean less  difficulty in registering one color to another when printing. All the colors that  are supposed to meet  or touch each  other will fall in the right  places in your  design.

To make a good  trap,  the light  colors should extend slightly into  the dark  colors. When printing, the light  colors are printed first  and  the dark  colors are printed over  them, thus  reducing the overlap and  rendering the exact size  of the color shape in your  artwork. Therefore, each  acetate will  contain a separate color. The  size  of the overlap depends upon  the width of the adjacent or outline color. When an entire pattern is covered by an outline which pulls  the images together, the underlying colors must  overlap into  the outlined area  but not surpass the outline.








First, analyze the number of colors in your  design and  note  where each  color appears in the entire image. Each  color will  need  a separate acetate or clear  polyester sheet.

To make multicolor artwork, you  will  need  registration pins,  a 1/4”  diameter hole  puncher and  a separate acetate or clear  polyester sheet for each  color. Before any  work has begun, gather the sheets together and  punch a hole  in the upper right  hand  corner, at least  2” above your  artwork, and  insert a registration pin.  Now  punch a hole  in the upper left hand  corner and  insert another registration pin (See  Diagram).

Tape  the pins  to the drawing board or a table  and  remove the plastic or acetate sheets. Tape your  artwork to the board and  place the first  acetate on the registration pins.  Using a marker, technical pen  or other opaque medium, trace  the first  color of your  design. When finished, remove the acetate and  replace with  the next  acetate. Trace the next  color. Continue this  process until  all the colors are traced on separate acetates (See  Diagram).

After you  separate all the colors (this  would include the outline that  pulls  the design together, if your  artwork calls  for an outline) place all acetates on the registration pins  with  the overall outline on top. Your overall outline or pattern that  brings the design together as a whole should not show spaces between colors when you  hold  the acetates up to the light. It may  help  to work on a light  box.









Summary

1.     Analyze the number of colors in your  design.

2.     Use  a separate acetate for each  color.

3.     Register all acetates simultaneously to each  other by punching holes in the plastic sheets with a 1/4”  diameter standard hole  puncher and  insert pins.  Punch the first  hole  and  insert the pin before punching the second hole  and  inserting the pin.

4.     Tape  the artwork to the drawing board. Tape  the registration pins  2” above the artwork.

5.     Place the first  acetate on the pins  and  copy  the first  color with  an opaque medium. Remove the acetate when completed.

6.     Place the next  acetate on the pins  and  copy  the next  color. Remove this  acetate and  continue until  all colors are separated.

7.     When colors meet, trap  light  colors by extending them  beyond the original artwork and  into the darker or neighboring colors. However, the overall outline color that  pulls  the image together should not be surpassed. This  master or outline color should bring the extended colors back  down to their  original shape and  fit perfect as in the original artwork.



Important Things to Remember

Proportion your  artwork according to the space you  are printing on. For example children’s “T”  shirts have  a smaller print  area  than  adult  “T”  shirts and  your  artwork should be reduced to fit that  space. When printing on paper you  may  want  to leave a border around the edges of the paper. Do not print  to the end  of the paper stock, because the image will  not print  clearly. (Also, you  will not be able  to pick  the paper up without getting ink on your  fingers!)

Opaque Areas in your  artwork or areas you  cannot see through will  print. Light will  not pass through opaque artwork and  the photo emulsion will  not cross link  during exposure time. These areas will  wash out when you  develop the screen and  while you  are printing; the ink will  pass through these washed out areas and  onto  your  stock.

Transparent Areas around your  artwork or areas you  can  see through will  not print. Light will pass  through the transparent or blank areas around your  artwork and  expose the photo emulsion causing a chemical cross linking that  will  harden around your  artwork. Your artwork will actually be formed by this  process and  become part  of the screen stencil.








Positives and  Negatives

What are positives and  negatives? Generally speaking, a positive is the image that  is not part  of the background. A negative is the background which is printed to create the image.

For example, in the images below, the cash  register’s shape or form  is outlined and  thus defined as a positive picture of the object. The  apple and  witch are also  positive images that  will print  as they  are drawn.

The  SOS  and  the globe are defined or shaped by the areas around them  and  they  are negative representations of the objects. The  opaque areas that  surround the SOS  and  the globe are the parts  that  will  print. Notice, the continents on the globe are positive images on the negative globe. The  transparent areas which are the images shaped or formed by the background will  not print. Ink  will  only  pass  through opaque areas in the artwork.

Film  positives and  film  negatives can be made by using a process camera and
photographic artwork which is in black and  white and  on paper. These work the same way  as hand made positives and  negatives and  print  as stated above.

It is important to keep  in mind the qualities of the ink you  are using and  the substrate you intend to print  on when making positives and  negatives. Some inks  dry slowly and  large  deposits of ink will  take  long  to dry.  This  may  affect the amount of time  it takes to complete a project as well  as what  difficulties a specific design may  introduce.






COATING THE SCREEN

Preparation

Once you  make your  artwork, the next  step  in the process is coating the screen. It is very important to wash the screen mesh to remove all sizing before you  apply the photo emulsion. If there  is oil on a mesh from  your  skin  or from  handling in the factory where the screen was  made, this  oil will  repel  the photo emulsion and  you  will  have  spaces in the coating which will  ultimately become unwanted open  areas in the screen. When it comes time  to print, ink will  flow  through these open  areas and  be deposited on the stock.




Using your  scrub brush, gently scrub the screen with  soap  and  water and  rinse. Then with  an abrasive cleanser, one  which does  not contain bleach, such  as Bonami, gently scrub the screen again. Be sure  to rinse  thoroughly. Allow the screen
to dry completely (a fan will  greatly decrease drying time). Now  your  screen will  be more absorbent and the photo emulsion will  better adhere to the mesh.

Photo Emulsion

Working in a dimly lit area,  mix  4 parts photo emulsion to 1 part  sensitizer. For example, 4 ounces emulsion with  1 part  sensitizer. Once mixed, this  solution is light  sensitive with  a short  shelf  life. Measure small amounts to prevent wastage. The amount of photo emulsion and  sensitizer you  will need  will  depend upon  the size  of the screen you  are using. Stir  this  mixture carefully to prevent air bubbles and  allow mixture to stand for about 10 minutes. It is best  to work in very  dim  daylight or use an amber bulb  because it is bright but will  not affect the chemistry of the photo emulsion.


Store excess photo emulsion and  sensitizer mixture in a plastic or glass  container at room temperature. Be sure  to store  in a darkened area.  This  mixture is good  for 3 to 4 days  at room temperature and  slightly longer if refrigerated. (If storing in refrigerator, use an opaque container which will  not allow light  to expose the photo emulsion.)

Expose the screen and  develop within seven hours after  coating it. If you  need  more time, it can still  be exposed up to 24 hours after  coating the screen. However, the screen must  be stored in a dark  area  until  you  are ready to expose it. Save  the extra  mixture to fill pinholes after  the screen has been  developed but again keep  it in a dark  area.  CAUTION: Never use photo emulsion on screens made with  pure  silk  fabric mesh.




Reclaiming the Screen or Removing the Photo Emulsion

After printing, many screeners prefer to leave the image on the screen for future use.  If you  wish  to do so, your  screen can be stored indefinitely. If however, you  choose to remove the image from  the screen follow these simple steps:

1.     Remove all excess ink and  return it to the container.

2.     To clean the screen, follow the instructions on the ink can label. For instance, if using water based ink,  clean screen with  water. If using oil based inks,  clean screens with  screen wash. It
is very  important to get all the ink out of the screen before reclaiming. Any  remaining ink will interfere with  the chemistry needed to remove the emulsion.

3.     Fill a tray  or a tub that  is larger than  the screen with  household bleach. Cover the mesh completely. Wait  5 to 10 minutes.

4.     With  a soft  scrub brush, gently rub both  sides  of the fabric.

5.     Stand screen up and  sprinkle or spray hydrogen peroxide on both  sides. This  will  create a foaming action. Scrub both  sides  gently and  wait  5 to 10 minutes.

6.     Using hot water, preferably with  a spray hose, wash the screen.

7.     When the screen is thoroughly rinsed, allow it to dry completely and  it will  be ready for reuse.

If needed, the process may  be repeated.








Applying the Photo Emulsion

After mixing the photo emulsion and  sensitizer in the exact proportions needed, and allowing the mixture to sit for about 10 minutes, follow the three  steps  illustrated below.








1. Turn  screen to outside and  pour  a sufficient amount of the mixture along the narrow side of the screen.




2. In a scraping action, use a coating bar or squeegee to spread the mixture smoothly over  the entire length of the screen. Scrape coat  outside of screen.




3. For a more durable screen, turn  over  and scrape coat  the inside of the screen from bottom to top. Turn  over  and  scrape coat inside of screen.




4. Turning to the outside of the screen, repeat the process but do not add  more photo emulsion unless there  are streaks and  empty spaces.




5. Always apply final  coat  to the inside of the screen.






Scrape away excess emulsion and  return excess to the container. Do not leave a heavy deposit of emulsion on the screen. Apply even  coats. Do not leave lumps or streaks on the screen. Be sure  the screen that  has been  coated does  not come in contact with  anything that  will  disturb its smooth coat.











Impression Couleurs multiples

Impression Couleurs multiples
Quand un projet est d'être imprimés commercialement, vous devez savoir quelles couleurs d'encre qui sera utilisée. Ce travail a une photo donc il doit être imprimé avec des couleurs CMJN. D'autres emplois peuvent n'avoir besoin que d'un ou plus spécialement mélangés "spot" de couleurs, habituellement décrit avec un certain nombre de Pantone.
Comme chaque couleur est imprimée de son propre course à travers la presse, il doit avoir sa propre couleur de séparation imprimé sur un négatif ou une plaque d'impression.

 


 
Impression d'encre cyan Impression Impression d'encre magenta encre jaune encre noire Impression L'impression terminée

  
La séparation finale négatifs sont créés par l'imprimante. Avant de livrer le travail, le concepteur doit toujours produire un ensemble de séparations positives épreuve laser pour vérifier les erreurs. Les séparations de couleurs sont créés lorsque vous imprimer le travail de l'ordinateur. La procédure exacte varie avec chaque logiciel, mais il y aura toujours certaines tâches courantes:

    
Sélectionnez l'imprimante.
    
Assurez vous d'avoir le fichier PPD correct (PostScript Printer Description) sélectionné. Il doit correspondre à l'imprimante que vous avez choisi.
    
Vérifiez la mise en page et les paramètres du document pour le format et l'orientation.
    
Mettez les couleurs dont vous avez besoin d'imprimer (plus à ce sujet dans la procédure de PDF). Pour être totalement sûr, vous pouvez activer toutes les couleurs, mais vous ne serez pas populaire, au bureau d'impression.
    
Allumez l'enregistrement des marques, imprimante, hirondelles ... ce qu'ils sont appelés dans l'application.
    
Définissez les options de saigner si nécessaire.
    
Choisissez les séparations ou option séparée; pas le composite.
    
Imprimer le travail.
Faites un Portable Document Format (PDF) la séparation des couleurs
Vous pouvez renvoyer les informations que vous avez envoyées à l'imprimante dans les étapes ci-dessus et l'enregistrer comme un fichier sur le disque dur. Vous pouvez ensuite ouvrir ce fichier avec l'application Adobe Acrobat Distiller, qui crée le fichier PDF.
Ce sont des avantages de l'utilisation de la méthode en PDF:

    
Vous pouvez visualiser les séparations que plusieurs pages sur l'ordinateur.
    
Vous pouvez activer toutes les couleurs, même celles que vous ne pensiez pas utilisé. C'est un moyen peu coûteux et rapide de découvrir des pièces qui se assigné à une couleur que vous n'avez pas l'intention d'imprimer. Si toutes les parties sont là où ils sont censés être, puis d'imprimer seulement les pages dont vous avez besoin pour votre preuve.
    
Vous pouvez sélectionner l'écran ou l'option de compression de bureau d'impression et de rendre votre fichier plus petit. Vous n'avez pas besoin d'envoyer un fichier de 20 Mo dans l'imprimante juste pour vérifier si des pièces mal placées. Lorsque vous imprimez à l'imprimante laser le PDF compressé sera procédé très rapidement.
    
Parce que le format PDF peuvent être très petites, il pourrait être envoyé à un client ou une imprimante dans une pièce jointe par courrier électronique.
    
Vous pouvez vérifier vos séparations quand il n'y a pas d'imprimante disponible pour votre ordinateur.
Voir les séparations PDF pour le travail à partir du haut de la page. C'est une bonne chose imprimée le concepteur de toutes les couleurs ... certains graphiques amené dans des couleurs supplémentaires et devra être fixée.
Comment faire un PDF:
Suivez les étapes pour faire les séparations d'en haut avec ces modifications:

    
Vous pouvez avoir besoin de sélectionner l'Acrobat Distiller ou Make version PDF de la PPD. C'est un processus de tâtonnements.
    
Vous pouvez avoir besoin de sélectionner l'imprimante virtuelle dans la zone d'impression PS du Sélecteur. C'est souvent le cas sur les ordinateurs à domicile.
    
Trouvez l'option pour envoyer le travail à l'imprimante ou de fichiers et sélectionnez Fichier.
    
Allumez le «inclure des polices" option.
    
Lorsque vous frappez la bouton Imprimer ou Enregistrer, notez où il est enregistré le fichier pour que vous puissiez le retrouver plus tard.
    
Une fois le fichier sauve (il aura une extension. Ps) ouvrir l'application Distiller.
    
Définissez les options de travail dans Distiller pour les paramètres de compression que vous préférez.
    
Ouvrez le fichier PostScript (le fichier. Ps) avec Distiller et il va créer votre fichier PDF. La boîte d'informations qu'il génère vous indique où le PDF est de sauver, si vous ne pouvez pas le trouver.
    
Ouvrez le fichier PDF avec Acrobat Reader.
    
Si tout a fonctionné correctement, vous pouvez supprimer le fichier. Ps, car il sera très grand et vous n'avez pas besoin de le sauver.
Certaines applications ont automatiques "Make PDF" options d'impression pour contourner le fichier et le processus de distillation. Si elles fonctionnent, il n'ya aucune raison de ne pas les utiliser. Mais, ils sont connus pour laisser sortir les choses, alors faites attention.