dry down percentages by paper
After reading Les's Dealing With Dry Down I thought it would be good to gather dry down data for common papers in one place. Unless I am misunderstanding something, dry down should be fairly consistent regardless of personal development choices. Each of us really doesn't need to do our own tests.
What numbers are you using for dry down with your paper d'jour?
I'll admit selfish motives--I haven't tested my papers yet. I'm playing with the uber-common Ilford FB and Ilford WT FB range and am hoping someone has already done the testing. If not, I'll bite the bullet and volunteer to test what I have.
With Azo I don't need a drydown factor, unless I am going to selenium tone then I reduce exposure 15%. John B
you should test your own but I when I use Ilford papers I use a precentage of 11% to subtract out of the exposues.
Can I proffer the hypothesis that the lighting under which you view your wet prints may have a marked effect on your drydown percentage, and therefore standard units may not be applicable.
I use 9% on Oriental VCFB
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Let me underscore the comment offered by Dave Miller.
The degree to which drydown is a problem that requires addressing depends on a number of factors:
1. the intensity of the light used to view the wet print
2. the intensity of the light used to view the finished print
3. the ambient light in the gallery area
4. all of the variables involved in post processing of the print - including, most importantly, the variables involved in toning
For these reasons, I suggest that the compensation factors used by others to address drydown many not have any application at all on the work that you do or the work that I do. Instead, it is necessary for each photographer to develop a dry down compensation formula for his particular selection of paper, developer, processing workflow, toning, darkroom lighting, gallery lighting, and even mounting/matting style.
A good start is just to have a bright light to find any visible defects and a second light for inspecting the wet print that is very close to the illumination level under which it intended to be viewed. Toning most likely will effect the gradation and/or color and depth of the print. After the viewing level standards have been devised and the effects of toning the papers you use are understood I would postulate that the next greatest change that may occur will be built within the paper itself. If you do the foregoing and have a drydown compensation based on your paper, developing toning then you may well have resolved most of your drydown problrem and feel no need not go any further.
In fact with some papers and a change in veiwing light and understanding of how the paper tones you may well feel that there is no drydown.
Claire (Ms Anne Thrope is in the darkroom)
I wrote about this in View Camera magazine last year, and published a table with dry-down percentages for, I think, 10 or 11 papers.
Most were 10%. Ilford Multigrade was 8%, I think. Seagull was 8%. Azo Grade 3 was 10%. Forte was 10%.
Does it vary with developer or fixer? Toned or untoned? I don't know - I didn't test for that. Somebody should. My intuition says it shouldn't matter, but in the other paper/developer tests I made, my intuition was always wrong...
That aside, it's a simple test that will teach you a lot about your materials, so you're best to do it yourself.
Thanks Bruce. That's exactly the kind of table I was hoping we could construct here by contributing personal data.
The lighting variables do complicate things. If the light in darkroom is not the same as the display conditions, then you are going to have a hard time making a fair comparison. In fact some recommend viewing wet prints in dim light to simulate dry down. These variable lighting conditions affect one's perception of dry down, but there is a distinction between perceived dry down and actual dry down.
Actual dry down will happen at the same rate regardless of light in the darkroom, light in the gallery, or the light anywhere. It is a simple increase in the density of the print as the print dries and the emulsion tightens up. This would be measurable with a densitometer if one were so inclined. The easiest way to see this is by using the same lighting conditions to view the wet print and the finished print.
Toning, of course, adds new variables so I'm referring just to straight print dry down numbers.
Performing tests with my Stopclock Professional Timer and my Saunders dichroic enlarger, I determined Ilford's RC paper dry down factor is only -1 and Ilford's fiber paper is -8. Nevertheless, this is subjective and it is probably advisable to perform tests yourself to arrive at preferable adjustment factors.