What Exposure Time produces the best results?
Room Temperature: 73 F
Humidity: Not humid
Name: Mady Lacaprucia and McKenzie Stuetzel Date: 10/10/17
For this experiment our goal was to continue to test various exposure times for the plates to determine which one produces the best results. We followed the same procedure of preparation as the previous test, except that we varied the exposure time. We applied three coats of emulsion and used a hair dryer in between coats to speed up the drying process. Most of the previous plates were exposed for five minutes, and Test 3 Plates A and B were exposed for four (drawn image) and four and a half minutes (photographic image); these plates were exposed for four and a half (drawn image) and five and a half minutes (photographic image.) After exposing and washing the plates of excess emulsion, we blow-dried them for about fifteen minutes, shellacked them, and printed immediately. We inked the plates using Gamblin Bone Black, mixed with 00 burnt plate oil. We printed the plates on the Praga press set to medium pressure with a pusher and a sizing catcher.
The exposure time on this plate was four and a half minutes. While washing this plate under warm water to get rid of the excess emulsion, there was some difficulty in removing the emulsion. While rubbing fingers gently over the surface of the emulsion side of plate, there was peeling of the screen off of the corners and edges of plates. I am unsure if this was due to temperature of water, too much pressure while rubbing, under exposure, or too much emulsion. This plate was still underexposed, and I continued to lose a lot of detail on the sides of my image due to one, or a combination of the reasons listed above.
The exposure time on this plate was five and a half minutes. This plate did not print well. It was clear that we had been overcautious in the stage of removing excess emulsion after exposing the plate, and that not nearly enough emulsion had been removed. The plate barely held any ink, and the image is barely discernible. Therefore, it ended up being impossible to tell whether or not five and a half minutes was a better exposure time for this image than five minutes.