RH Designs Analyser Pro Calibration questions
I have an Analyser Pro and have a few questions after reading the calibration manual and attempting to follow them.
1) After following the directions regarding making the test strips for determining exposure corrections, some strips at the extreme grades look completely blank.
For example, using Ilford Multigrade Matte Fiber, contrast grades 1, 2, 3, 4, and 5 look fine but grades 0 and 00 don't have any hint of gray scale.
Using Fotokemika Varycon Matte Fiber, only grade 5 has this problem. I did follow the instructions and decrease grades 4 and 5 exposure by one f-stop for both papers.
Is this OK? Using the 1/4 stop steps, I just used (-9) as my exposure correction factor for the contrast grades that had no gray scale.
2) after calibrating and entering the exposure correction factors for each grade for each of the papers, I made the contact test prints for calibrating the contrast values for each paper. I first started out with grade 00 and had to increase my exposure times to about 26 seconds for the Fotokemika and 78 seconds for the Ilford papers to get an adequate black.
Do I leave the settings the same except for selecting the appropriate contrast grade that I want to calibrate on the Pro (similar to exposure correction) or can I adjust the exposure time with each grade individually to get a true black/true white print? In other words, will changing the exposure time for each grade upset the standarization process in calibrating each paper?
If there is no hint of tone on the paper then you need to increase exposure, so the factor should be +9, not -9. That is probably the reason the test strips are still blank. Grades 4 and 5 are usually the ones that cause most trouble because small exposure changes lead to big density changes.
Grade 00 is also troublesome because some papers (including MG IV as you've found) don't produce a really good black at this grade.
When calibrating the exposure corrections you should not change the exposure time after taking a light reading. (The only exception is at grades 4 and 5 if you are not using Ilford filters.) Normally a single reading is sufficient to calibrate all grades - the Analyser will recalculate the required exposure as you change the grade setting. Be sure that the grade settings on the Analyser and enlarger always match, otherwise calibration will fail.
You can take a new light reading for each grade, but there is no need to. Just be sure when you change filtration you change the Analyser's grade setting to match.
Hope that helps!
Thank you for your quick response. You were also very helpful and receptive on the phone. It is good to know that your products are well supported.