Thursday, December 17, 2009

Prior Proper Planning Prevents .....

When working with photopolymer processes it's extremely important to do test plates to get the light exposure correct for the particular image you're working with. You need to adjust for the density of your negative, the materials used to create it, your particular light source, use of an aquatint screen and the type of photopolymer film or plate. Too much exposure and you burn out the detail in your image and get a very light print. Too little exposure and you don't get enough detail.

Now, I will be the first to admit that patience is not one of my strong points and I love to just jump right in and see what happens. This often works because of my past experience but there are times when an image just wont print as intended and there is no other alternative than to step back and do some exposure tests.

I adhered one layer of ImagOn to a copper plate and exposed it to an aquatint screen. The screen I favor is produced by Elizabeth Dove (I met Elizabeth in 1995 when we were attending one of Keith Howard's Masters Workshops in Peace River, Alberta. She went on to do a lot of research with the photopolymer film and is featured in Howard's books.)

I "step" exposed the aquatint screen to light units in increments of 10. After removing the aquatint screen, I placed the image negative over the plate and exposed that to varying amounts of light. This test plate was developed and printed and I was able to determine which exposure, for both the aquatint screen and the negative, worked best for this particular image. I made a new set of plates using the appropriate exposure times and was happy with the results. Now, if I would just do this with each new image I would save myself a lot of time and frustration.

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