May 7, 2015
Researchers: Kevin Pomerleau/ Daniel Chiaccio
Room Temperature: 65 degrees F
Materials: Macdermid Plus 8000 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 and exposure time of 7 1/2 minutes will print a clearer image containing a greater PPI (pixels per inch)
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 (a new transparency with a higher pixel count/refer to “How to halftone an image in photoshop”) by placing the transparency, emulsion side up, onto the exposure unit with the emulsion coated screen face down over it (emulsion to emulsion). We then covered the entire unit with an opaque black trash bag and 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.
Conclusions: The image printed clearly, with roughly the same amount of detail from test no. 5, all text printed clearly, and we had a successful amount of information in our mid tone areas. Even though the image quality was similar, We concluded that it was best to use a higher pixel count to obtain the optimum amount of detail and reduce and chance of a grainy image.
Although we were successful in creating a high quality image using the Macdermid Emulsion on a 17×15″ screen, we still needed to see if we could get the same quality image on a screen that exceeded the size of our exposure unit, and would be able to be used on our new Filbar Machine. For our next test, we will attempt to expose a 47×34″ screen on our 35×20″ exposure unit, and see if the lack of contact the screen makes with the exposure unit can be compensated with extra weight.