SCREEN PRINTING

Below is some of the info that can help you navigate the Print Lab when you need to screen print. Note the information below are just some of the process for using the equipment and the lab, for specific questions email Dansby.

1. Obtain a screen. You can purchase one at either locations:

2. You must tape the frame of your screen before using it in the Lab. Taping will keep emulsion and other chemicals from seeping into the area where the mesh and frame join as well as protects the vacuum frame glass.

3. The screen must be clean before applying any new emulsion. If the screen has been previously used, there may be emulsion on the mesh. Apply emulsion remover from the green container in the blowout room. Re-apply to any stubborn spots and wash away with water - DO NOT LEAVE ANY TRACE OF EMULSION REMOVER ON SCREEN, NO MATTER HOW DILUTED.

4. Degreasing - Apply a small amount of Degreaser ( red container) on a clean rag, distribute over screen mesh & frame, and then wipe over entire surface of both the top and bottom of the screen. Let degreaser sit on screen for a minute, then rinse rinse thoroughly with the water sprayer. Do this 3 times. After the third wash & rinse, remove water with air hose and blot with towels outside of the blowout room. Then place screen on the drying racks, bottom side up. Turn on the fan for at least 25 minutes. There should be NO WATER dripping from the screen at this point, as this is a hazard to the screens below it on the racks.

5. If the screen is old and has tears or rips in it, first determine if they're so big they'll interfere with your image. if so, use another screen. If not, using tape, on the top AND bottom of the screen mesh, patch the rip.

1. To begin, obtain emulsion, either from the cage or from a commercial seller. A pint is more than enough for multiple uses on any screen. Emulsion obtained from the cage will be light sensitive. Emulsion bought commercially will more than likely have to be mixed in order to bring about light-sensitivity. Instructions are on the packaging. Either way, once you have a light-sensitive emulsion, DO NOT expose it to light for any period of time. Try to only open it in the darkroom.

2. Obtain a scoop coater from the lab tech. Choose a size compatable with your IMAGE size, not nessesarily your SCREEN size. i.e. one that will coat the screen with enough emulsion to cover your image and the area just up to your tape. The maximum size scoopcoater should cover just inside the tape on your frame, but not contact tape when coating. Scoop coaters are available for 24 HOURS max. You must return them to the lab tech when you are done. DO NOT, however, return them without CLEANING them first. Clean the scoop coater in the blowout room by filling it with water and squirting a small amount of emulsion remover into the water. Let this sit for 3 minutes or so and rinse. Pay attention to the bottom of the "blade" area ( where coater contacts the screen) and any crevices on the scoopcoater. If you have trouble geting all of the emulsion off wipe with a small amount of alcohol on a rag. Remember to return the black rubber edge protector with the scoopcoater.

3. Gather your : scoop coater, your screen, your emulsion, some newsprint or scrap paper, and some small cards, either cut from index cards or card stock - some are usually lying on the grey table in the lab and go into the darkroom.

4.In the front room of the darkroom, on the floor, layout your newsprint or scrap paper. Place your screen against the wall on the paper with the BOTTOM (the flat side, not the recessed side) FACING OUT towards you. Open your emulsion and place your scoop coater on the floor in front of you.

5. Fill the resevoir of the scoop coater with a very small amount of emulsion - 1/8" to 3/16 "should be good for most small and medium screens.

7. Lift the scoop coater to the screen, and let it rest on the bottom edge of the screen, or, if you have taped your screen, let it rest just above (1/4") the bottom tape. Tilt the coater towards the screen until you start to see the emulsion flow towards the screen. Watch to make sure it is flowing evenly across the blade of the coater. If not, tilt the coater slightly down on the slower side as needed in order to make an even flow.

8. When the emulsion touches the screen uniformly across the length of the scoopcoater, begin to pull the coater up the length of the screen in a smooth motion. Maintain a little pressure to assure contact with mesh throughout pull. As you approach the top of the screen, tilt the coater back to stop the flow of emulsion over the blade, pause and then pull the scoopcoater away from the mesh. Take care to not drip! It is best to finish the coating before reaching the top tape to avoid a puddle at the top.

9. Place the scoop coater out of the way on the newsprint. Take your small cardboard pieces and scrape the excess off the sides and top of the screen, both sides of the screen, until you feel that no drips or bumps exist. (any uneveness will affect your image.)

10. In the middle room of the darkroom, you will find on the right and left, drying racks. Place your screen, with the BOTTOM FACING UP on the rack, turn on the fan timer near the door on the right for MINIMUM TWO HOURS, and walk away. Drying times vary - check on it periodically - if the emulsion feels even slightly sticky, give it more time.

If the rack is full, as it often will be, find some pieces of cardboard or other such materials, place four small pieces at the four corners of a similar sized screen on the rack, and place your screen on top of it, wedding cake-style. MAKE SURE there is room between the two screens to allow air flow.

Do not place two screens bottom to top on the drying rack. Do not place your screen on the rack face up. Remove your screen when it is dry to free up space for others.

1. Retrieve your coated screen from the darkroom drying rack. Walk through the black curtains into the shooting area. You will find a large vacuum table and a lamp sytem.

2. The vacuum frame is the large table to your left. It has two parts, a top metal frame with neoprene, and a bottom frame with glass. Make sure the vacuum frame is inside of the blue tape "footprint" on the floor.

3. *Note* the bits of emulsion and other materials on the glass. This residue will appear on your image if not cleaned. To clean ask lab tech for assistance or if during afterhours place a rag with warm water on spots for a minute or two then clean with dry rag. If you can't reach spots use the mop to push rag on unreachable areas. ALWAYS dry glass thoroughly before use. DO NOT place wet/damp/sticky screens or anything else besides a well dried, coated screen ready to be shot on this glass.

4. Place your transparency face up roughly center on the glass. Place the bottom of your screen over it - align the two to your liking. Sometimes, it may be a good idea to tape the transparency to the screen before hand, if you're having a hard time lining it up on the glass and to prevent any slippage of the transparency when you expose. Place string across frame and cover the screen with the black sheet.

5. Close the top of the table. Lock the table parts together by pulling the white metal handle on the right to full vertical. Pay attention to both the latches on either end of the table. MAKE SURE they close and lock around the bolt. Pull on the handle and note alignment marks on locks and bolts to be sure of this.

6. Reach around the right of the table and find a small chrome switch. Flip it upwards. You will hear the compressor turn on. This will vacuum contact the screen and transparency to the table top. You will leave this on during the entire shooting process. Allow it a few moments. You will start to see the outline of the screen appear through the neoprene as the screen is vacuumed to the table. USe this time to turn on the power the lighting timer and allow the lamp to warm up. ( see instructions under lamp head).

7. Find the small white metal latch just below and to the right of the large handle. This releases the vacuum part of the table from the legs and allows it to tilt to vertical.

8. Using the large handle on the bottom of the table, SLOWLY lift up the table top until the table stands vertical and the rubber stoppers touch the legs of the table at the bottom. DO THIS SLOWLY - do not let the table bang against the table legs.

9. When the table is vertical, approach the lighting rig. It is a very very powerful light. Everything you do with it should be done with this in mind. Do not stare at the light when it is on. Do not expose your skin to the light for very long. Skin damage can occur from just a few moments of exposure, and permanent retinal damage could occur from looking directly at the light or at its reflection in the glass of the table.

There is an orange timer on the base of the lighting setup. There are instructions next to the timer. Always let the lamp warm up for approx. two minutes, then consult the chart next to the box. Refer to your imaging material and choose the preset that most closely matches your imaging materials. Press "Memory" on the timing box, and select the appropriate preset number. If the selection you have chosen does not show the number of seconds that the sheet says it will, go get the lab tech - they will reset the machine properly.

10. Press "Start" The unit will give you about 8 seconds to leave the room. It is highly recommended that you take this time to do just that. Wait outside the exposure area. This is a good time to set up the blowout room and blotting area.

11. When the light has gone off, reenter the darkroom. Switch off the power of the lighting unit. Return the frame to the horizontal position. Switch off the compressor. Give the neoprene at least 15 seconds to depressurize. Unlock the frame top, take your screen and transparency out.

12. Bring your screen into the blowout room. It is okay to bring the screen out in the light briefly at this point.

13. Set the screen leaning against the back of the large sink-like structure at the end of the room. If the light is not on on the blacksplash, reach around the back of the unit on the right side ( on the large sink) and find the switch.The smaller sink has a switch on the floor ( a black rubber " bump")

14. Use one of the sprayers to wet both sides of the screen and then alternate spraying gently front and back switching aprroximately every 10 or 15 seconds.

15. As the water runs over the screen, you will begin to see your image slowly emerge, first as a lighter shade than the emulsion, then eventually, the emulsion will start to fall away. This shouldn't take more than a moment or two. Turn the screen around as you do this - sometimes at the front, sometimes at the back.

16. Sometimes the image doesn't quite blow out in small, detailed areas. Here it is acceptable to sometimes try a bit more concentrated spray, for short blasts on very small specific areas. Use extreme caution if this is needed.

17. When the image has developed to the point that light can be seen clearly though it, take your screen to the airhose and spray out water, then to blotting easel to the right of the Blowout Room door. Using the towels there, blot the rest of the water off of your screen.There should be no water dripping while in the production or drying areas. Take it to one of the drying racks with the large white fans on the other side of the room. Find a space by either moving other screens around or stacking your on top of another, wedding-cake style, always using cardboard or wood shims of some sort to allow air flow. Turn the fan on and walk away for minimum of 25 minutes, You have completed shooting and developing your screen.

You have shot your screen, developed it and dried it. The image has come out to your satisfaction and you are now prepared to print it.

1. First, obtain ink and paper. You will need scrap newsprint paper for "work-ups" or scrap prints and good paper for your final edition.

Ink is occasionally a complicated matter. Some companies' ink dries quickly, other dry slower. If you are interested in making t-shirts or metal, glass, plex or wood you should use an additive called Activator. There are other additives in the Lab as well. Do research ( see Know Your Chemicals on this website!!!!) - this are the only way to determine what ink and additive is right for your project.

2. Once you have you materials, proceed to one of the large printing tables in the lab. You will find clamps on the outside edges of the table. These clamps can be adjusted above and below the table. They can be moved into other slots to make room for different sized screens as well. Make sure that the screws in the clamps have washers on them and that the screws are firmly tightened.

3. Find a set of clamps that works with your screen. Place your screen in the hinged clamps on the table, with the mesh flush on the table (not upside down, where the mesh is raised). The clamps are secured underneath by wing-nuts. Again, make sure they are tight before you begin. Rest your screen on the feet and screw the tops down on the outer edge of the screen.

4. Lay out your work space around your screen. You will need:

  • ink
  • screen cleaner - the large clear plastic bottle appropriately labled.
  • rags
  • paper - good and scrap
  • a squeegie, obtainable from the lab tech
  • pull a large drying as close as possible to your table
  • obtain tabs from the cage

You may also want to have handy Retarder, Activator, or Extender, depending.

5. All these items are defined in Definitions, if you have any questions. Using a piece of your nice paper, lift up your screen and align the image on the screen with where you want it on the paper. Once you are confidant, reach for your tabs.

6. Using two tabs on the bottom and one on the side of your paper, align the tabs to the edge of the paper. Tape the tabs down on the outside corners before you remove the paper. Remove the paper, prop up your screen, and tape the tabs down further, per the diagram.

7. Before using your ink, there are various additions and adjustments you can do to the ink. First, and most easily, you can mix colors. Usually, you'll want to estimate the amount you'll need for your edition and mix that amount separately in another container, rather than ruining your original supply.

If the ink has a tendency to dry quickly, you can add, in very small amounts, Retarder. Again, do it in a separate container with only the amount of ink you'll use for your run.

Extender can be used to, literally, extend the ink through your run. If you have mixed a specific color, and find yourself running out of that color before your run is complete, adding a small amout of Extender can lengthen the use of that ink, without losing thickness.

Lastly, Activator can be used to strengthen an ink for use on formats other than paper, such as cloth or CD's. You may not need to use any of these until further into your run, but its important to have them at hand before you begin printing.

8. Begin by placing a piece of scrap paper under your screen. Take your ink, and pour a small amount about half an inch thick, along the length of your image, at the bottom.

9. Lift the screen off of the paper, and using your squeegie, pull the ink in a smooth and even motion from bottom to top. This is called the flood stroke.

10. Lay the screen back down on the table, and using the same even pulling motion as before, pull the squeegie down the screen. Do no press very hard with the squeegie - only use the weight of the squeegie and the pressure of yoru hands. The rubber of the squeegie should not bend - it should maintain a 45 degree angle with the screen at all times.

Lift up the screen and examinine your print.

Too light - you can make multiple pulls on one piece of paper - only don't flood the screen every time, just pull the excess ink at the top of the screen to the bottom.

Too dark, or the image bleeds out to the sides - you may be using too much ink, too much pressure on your screen or your screen may be faulty. Using Screen Cleaner, scrub the bottom and top of your screen to remove the ink, and begin again.

12. Often it takes more than one "work-up" or test print to get the effect you desire. Do as many work ups as it takes, as quickly as possible, to preserve your ink, and then begin your edition.

It is easier to print with a friend, and this part of the process is where that comes in really handy. Have your friend stand by with the stack of paper. You stand at the screen. The friend slides the paper into the tabs, you lower the screen, print and put the paper on the drying rack while your friend aligns the next piece. This process will make everything go much faster and allow you to get as much printing donewith your original amount of ink.

You have shot your screen, developed it and dried it, and now printed it.

1. In order to begin cleaning, take your bottle of screen cleaner and a couple of rags. Place a piece of scrap paper beneath the screen. Use a cardboard card to remove as much ink as possible. Then, apply screen cleaner to the screen mesh where the ink traces remain.

2. TWith the rags, scrub the ink off the screen. Stand the screen up and scrub the back as well. Try and remove ALL of the ink.

3. Even small amounts of ink can damage your screen, wipe with papertowel to determine if any residue is still present.

4. Dispose of all the rags in the red cans found around the lab - do not wash them with water or throw them in the garbage can or put them back in the wood bin they were found. Rags that are less ink saturated can be put in the yellow can and reused in a pinch.

5. The screen can now be prepared for next image.

- QUESTIONS? -

ROBERT DANSBY

LAB DIRECTOR

RDANSBY@CALARTS.EDU