TESTS
Previous tests can be seen in this archived page, but the exposure times were about 6 times what they should be, according to the following series of tests.
To determine the correct exposure time for Van Dyke Brown prints, it's first necessary to determine how long it takes to get the densest brown without overexposed solarization (the metallic sheen in the darkest areas of the previous tests).
Test 1 : Large Increments
Method: In increments of 100 LU, expose a sheet of sensitized paper without a negative
Materials: Chemistry: Bostick & Sullivan's Aqueous VDB solution, Paper: Crane's Kid Finish
Results
The
correct exposure is somewhere between 100 and 200 LU (the gray cast on this
scan is indicative of the shimmery silver solarization).
The next step is performing a step test between 100 and 200 to nail down the exact LU.
Test 2: Small Increments
This scan is a bit more difficult to read, due mostly to the slight changes in shades and a rather uneven coating job. I settled on 140 as the new exposure time -- quite a far cry from 610.
I applied one of our best-results negatives to a new sheet of sensitized paper for Test 3.
Test 1
Curve: Modified S Curve
White: 11%
Black: 91%
Film: Pictorico Ultra Premium OHP
Printer: Epson 7600 Photo Dye
Method: Burkholder template, 16 bit, 2880dpi
Image Results
There is quite a bit of loss of highlight detail, and now the darks are not nearly dark enough. However, the results are still encouraging and there will be further tests on 22 June.
Step Tablet:
