Successful Experimenting

I'm beginning to finalize an idea for my rock piece. Just like the dune is comprised of carefully placed individual boulders, I'm thinking of creating a series of small individual plates focusing on cracks and crevasses and then assembling them on the press bed to print as one unit.

First, I need to do a few test pieces to get my positives and exposure times correct. This is always the trial and error period before I can get down to business.

I'm a self taught novice when it comes to working with Photoshop. I learn as I go along and try to pick up tips and techniques from various sources. There are some pretty good tutorials online and it's just a matter of taking time to sit at the computer and experiment.

Film positives. The one on the right with curve adjustment.

I was having trouble getting details in dark areas. Even though I was using an aquatint screen there were areas of open biting. I decided to take the time to experiment and see if I could solve this problem once and for all. Dragging out my Photoshop books I came across a section on "curves".  It sounded as though the blacks on my film were too dark.

Because the image is translated into a dot structure, the blackest areas need to be reduced from 100% to around 70% for ImagOn and 80% for Solarplate. With this information, I created two transparencies on Mylar. There were no adjustments done to the one on the left. The one on the right  had an adjustment using curves. The adjusted transparency looks lighter and has a gray tone.

ImagOn plate, transparencies & proofs.

To keep exposure and processing times the same, I exposed the two transparencies to the same surface - ImagOn adhered to a sheet of plexiglass . Using a NuArc exposure unit, the plate was first exposed to an aquatint screen for 20 LU's and then the image was exposed for 35 LU's. It was processed in a soda ash bath for 9 minutes.

Transparencies on top - proofs below.

After proofing the plate, I was happy with the results and surprised to see what a difference the adjustment made. The image above shows the two transparencies and their corresponding proofs. The plate that was made using the 70% transparency has much more detail than the darker transparency. More light was able to penetrate the image during exposure to provide greater detail. Eureka!

So, once you have your image, click Image - Adjust - Curves. Pull the right end point of the graph straight down towards the middle of the system of coordinates until the Output field shows 70% for ImagOn and 80% for Solarplate. Then click OK and print your transparency.