Angle: The Basics of Screen Printing


Procedure and Class Notes

Health and Safety

  • Sensible footwear
    1. No open toes
    2. No open heels
    3. No slippers
  • No drinks or food
  • Long hair has to be tied
  • Lanyard tucked in
  • Don’t wear nice clothes
  • Wear aprons

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Printing with the Screen

  • You can print on anything flat
  • Screenprinting is done in layers, one color at a time
    1. However, you can end up with more colors on the sheet than you printed because of overlays and overlaps
  • Stencil-Based Process
    1. Can use paper to block off areas of the mesh to print
    2. Photographic stencils most commonly used
      • Emulsion is exposed to UV light over the positive
      • Emulsion hardens where the light shines through and remains soft where the positive is
      • The un-hardened emulsion is washed off and the image remains in the screen mesh
    3. Positives
      • Image of what will be printed in different layers of color
      • Can be done in many different ways
        • Marker
        • Print
      • The Screen
        1. A screen is made up of a frame with mesh fabric
        2. The screen is fragile
          • Always check for sharp objects
          • When using scissors, always cut away from the screen

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Ink

  • The ink used for screen printing is water based
    1. Acrylic mixed with the printing medium
      • Cannot print without it
      • Without the medium, it is far too much
  • Ink is free at LCC
  • Unique inks
    1. Metallic
    2. Thermo
    3. Conductive
    4. Glow in the dark
  • Mixing ink
    1. Place printing medium in the container first
      • Doing this will prevent the ink from sticking to the side
    2. Use 50% or more medium per ink mix
      • The more medium, the more transparent it is
    3. Use the spatula to stir the paint in
      • Mix acrylic into the middle and move to the outside
    4. Test on both white paper and the same kind of paper you will be using for your project
      • Gives you a better understanding of how it will turn out
  • Ink is usually applied from lightest to darkest
    1. Sometimes this is the only way layering will work properly, but it depends on the color, paper, and projects
    2. If you want to print neon on black, do the print in white first and then lay it over on top
    3. Preparation is key
  • Do not store ink on the table so it does not get on your project
    1. Store it below the table or next to you, but be careful of blank paper next to you

Steps

  • Tape out the screen
    1. Stops the ink from going through the edges of the screen and onto the table
    2. Makes cleaning easier
    3. Procedure
      • Stretch out tape longer than the screen
      • Pull so the tape bends in half
      • Put the tape down, half on the mesh and half on the frame
      • Smooth down and create as few wrinkles as possible

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  • Preparing the Handbench
    1. Also known as screen bed
    2. Holds the screen while printing
    3. Holes in the bed act as a vacuum and suck the paper to the bed when printing
    4. Weights are attached to the back of the handbench and keep it up and down as necessary
      • You must keep control over this so it does not snap back
    5. Handbenches also have a squeegee arm
      • Allows you to apply even pressure on large substrates
    6. When leaving, always make sure to tighten the knobs and leave the handbench up
  • Placing the Screen
    1. Open the side arm
    2. Place the screen flat on the table
    3. Position the screen and place it on the sidebar so there is a gap between the table and the screen
      • This gap is called the “snap” because the screen literally “snaps” back to the original form after printing
      • This is ALWAYS present when printing on hard surfaces, but NEVER present for textiles and soft surfaces
    4. Tighten the arm just enough to hold the screen
    5. Clamps click in place
  • Positioning and Registration
    1. Position the positive where the print should be on the page
      • Tape the positive in place
      • Fold a piece of paper and attach it to the bottom of the paper (known as a “helpful arm”)
      • Use the helpful arm to alight the page underneath the screen
      • Tape the arm to the table
      • Tape the paper to the table
  • Remove the arm and stick it to the side of the table for further use

  • Align Lay Stops
    • Place three tented lay stops on the corner and one side of the aligned print to mark where the paper needs to be for printing
      • Called “3-point-registration”
      • Only one side necessary because paper sizes vary slightly per individual page
    • Mark where the middle of the tented lay stops fall on the page
      • This helps if you want to return to the design
      • The sheet which is marked up is called the “lay sheet” and it is the master copy

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  1. Registration
    • To register means to line up the different colors and screens so that the design falls correctly and the overlay colors print well
    • Use lay stops and the helpful arm to do this
  1. Mask out the table
    • Small pieces of tape on the outside and longer pieces of tape on the inside so the pages do not flutter
    • Keeps the holes clean
    • Covering the holes makes the suction stronger
    • Do NOT cover the lay stops

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  • Select your squeegee
    1. The squeegee is a handle with a rubber blade
    2. The purpose of a squeegee is that it pushes ink through the holes in the mesh
    3. Select a squeegee just slightly bigger than the image itself for full and even coverage
  • Start printing
    1. The printer is the only one in charge of the machine at this point
    2. Turn the vacuum on to keep the paper in place
      • It will automatically turn on and off because of an internal mechanism during the process
    3. Lower the handbench and lean it on your hip above the printing surface
    4. Flood the screen
      • Place ink in the front and pull towards the back
      • You don’t need to push down hard
      • Always make sure there is fresh ink, otherwise, it will come out streaky or not at all
        • Dries very quickly
      • Cover the entire width of the squeegee
      • One stroke back to flood and one stroke back to print
  • Print
    • Lower the handbench onto the table
    • Pick up the squeegee from the back
    • Press down with both hands and pull towards you
    • When finished, flood again and place squeegee in screen
    • Raise handbench and remove the print
    • Keep the lay sheet
  • Cleaning
    1. Cleaning is done in place on the table
    2. Scoop up ink with reusable plastic card
    3. After this, spray the screen with water
    4. Use rags and squeegee to push ink onto a scrap paper below
    5. Wash the bottom of the screen
    6. Dry with rag

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  • Additional printing parts
    1. Repeat above steps
    2. Use lay sheet to register
      • Always print on lay sheet first for every layer
    3. Use the handy arm and positive to reposition
    4. Print again
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