May 7, 2015
Researchers:Kevin Pomerleau/ Daniel Chiaccio
Room Temperature: 65 degrees F
Materials: Macdermid Plus 8,000 Universal Resistant Emulsion, 17x 15″ screen, Speedball Screen printing ink with extender, Exposure unit, Opaque Black Trash Bag, 2.5 lb paper weights
Abstract: To see if an exposure time of 7 1/2 minutes using the Macdermid Emulsion will provide us with a higher quality image with more detail in our halftone areas.
Procedure: Using a 14″ scoop coater, We coated a 17 x 15″ white 195 mesh count screen. After letting the emulsion dry for 45 minutes under ventilation, we exposed a pre made transparency using both halftone and text (the same transparency from test no. 1) by placing the transparency, emulsion side up, onto the exposure unit with the emulsion filled screen faced down over it (emulsion to emulsion). We then covered the entire unit with the opaque black trash bag and the 2 paperweights and set the exposure time for 7 1/2 minutes. Once the exposure was finished, we removed the weights and trash bag, and walked the screen to the washout booth (in a non light safe room) and washed the screen out.
Conclusion: Due to the amount of mid tones obtained in this print compared to our other tests, we concluded that this was the best exposure time we had experienced yet. The text printed clearly, and we were able to obtain the greatest amount of mid tones, which were apparent in the tiny circles found in the corners of image. The image of the koala didn’t experience any extreme blow outs (large areas of underexposed screen that over print without any detail), however it still lacked a significant amount of detail.
After five different tests on the same transparency we came to the conclusion that we needed to focus less on the application of the emulsion to the screen and more on the quality of the original transparency. For our next test we will change the process in photoshop, from a Threshold image (an image made of tiny blocks) to a pixelated image (an image created using tiny circles/dots) while using imagery with a greater amount of detail, and halftones.