Screen Printing

1. Screen Printing

2. Historical Background • Egyptians and Greeks used stenciling • 1907, Samuel Simon of Manchester England patented process of using silk fabric as printing screen • John Pilsworth developed multicolor process of silk screening

3. Screen Printing • Advantages: Print on any surface that will accept ink • Print on irregular/ cylindrical surfaces • Print thick abrasion and weather resistant ink films

4. Process • Screen Printing Process-Scoop coat mesh with Direct Stencil • Output positive separations • Expose your emulsified screen with high intensity bulb, this will harden the emulsion on screen • Wash out the exposed areas of emulsion • Blackout any areas that may have been exposed or accidentally blown out

5. Process Cont. • Tape edges of the screen, where there is not emulsion. (this helps with clean-up) • Mount and position from on the press • Begin to print • Remember to clean your screen • Wash and position frame on the press • Use chemical spray to remove your stencil • Use chemical called Dehaze to remove any shadow left behind • Degrease your screen, this allows your next image to better adhere to your screen

6. Screen Printing Components • Wooden Frame • Easy to build • Low Cost • Subject to expansion and contraction, which also means that it is subject to damage and warping due to the chemicals and or the water used during the screen printing process • Need to coat with water proof sealer

7. Screen Printing Components • Steel/Aluminum • Expensive compared to wood frames • Less prone to damage from chemicals • More rigid than wood frames, retains size • Frames larger than 36x36” should be constructed of steel

8. Screen Fabric Types • Natural silk, which has limited use today • Synthetic polyester, nylon, which has a wide array of applications • Metal mesh, for use with heated inks on poly

9. Fabric Tension • Need correct tension to produce quality printing • Fabric manufactures provide tension specs • Measure by percent stretch measure by tension meter

10. Stencils • Hand cut stencils • Paper cuts • Inexpensive • Not used for production runs • Placed under the screen

11. Stencils • Water soluble • 2 layers, support layer and gelatin layer • Cut and remove gelatin layer • Adhere under the screen • Cannot use water soluble inks

12. Stencils • Burned Edges • Material cut wit dull knife • Fabric not degreased before adhering fabric • Screen was not immediately dried after area is washed away

13. Stencils • Indirect, which means that it is exposed separately from the screen fabric • Can be exposed in a plate-maker • Stencil has three layers • Light sensitive gelatin layer • Support base • Adhesive layer to bond gelatin and base

14. Stencils • Direct, a thin coat of light sensitive emulsion applied to screen fabrics • Expose in a deep bottom vacuum frame • Image area hardened and non-image area washed away

15. Masking/Taping Screen • Masking works will for blocking non-image areas in production runs, that way the ink will not run off the screen and clean up will be easier

16. Screen Printing Inks • Match ink to substrate • Plastisol used for textiles • Required high intensity heat to dry • Lacquer based if used for wood

17. Printing • Use of a squeegee to draw the puddle of ink across the stencil opening with one smooth motion. • This should be done at a 60 deg. Angle In class we will be using a water-soluble stencil The fabric that will be used is Polyester