Problems and possible solutions to the print SILKSCREEN
Problem: Drawing Fluid, Screen Filler or Photo Emulsion won't adhere to screen.
Screen fabric dirty. Screen may have been used with solvent based materials or the sizing may not have completely washed out of the screen fabric.Scrub with a soft bristle brush and a dish washer powder/ water solution. Rinse well.
Problem: Photo Emulsion will not wash out to create a stencil.
Artwork not prepared with a visually or photographically opaque material.Heat as well as light will "set" the photoemulsion. There must not be any heat build-up (above 105 Degrees F) on the stencil during exposure.More than 12 hours (at 70 degrees F.) elapsed before the sensitized screen was exposed (Speedball Bichromate System).The sensitized screen was exposed to too much light or heat before exposure to art work.Overexposure. The instructions lists exposure time and heights for a "disposable foil pie tin" reflector. More efficient reflectors will require a higher bulb height and/or less exposure time.Artwork did not make proper contact with screen. Incomplete washout.
Problem: Too much or all Photo Emulsion washed out of screen after exposure.
Improper mixing of emulsion and sensitizer.Underexposure.Tracing paper or film not sufficiently transparent. Washout temperature was too high.Screen not dry before coating.Screen not dry before exposure.
Problem: Some small details on Photo Emulsion screen did not wash out completely.Possibilities:See relevant "Possibilities" under "Photoemulsion will not wash out to create a stencil."Failure to use a black, non-reflective background under the screen during exposure.Using a more intense light source, such as the BBA No. 1 photoflood, will reduce the required exposure time and resultant light bounce-back. This will improve detail wash-out.
Problem: Inks drying in screen.Possibilities:Use the flood stroke technique given in the instructions. Keep squeegees sharpened.For the Acrylic Screen Inks and Textile Inks, mix with the Retarder Base.Use a couple of humidifiers or "sick-room" vaporizers in the printing area.
Problems: Textile ink prints not opaque enough.
Use a coarser scree!n fabric. Make multiple passes.Use a rounded squeegee.Use a soft base under the fabric to be printed.Use a hair dryer to flash dry the print immediately after printing and then reprint overtop in exact register.