BTW, hydroquinone is in the same family of chemicals as pyrogallol and pyrocatechol and is only slightly less toxic. It is used in a wide variety of film and paper developers but you rarely read anything about its toxicity.
My guess is that many routinely used household cleaners, are more toxic than what we use only infrequently in the darkroom.
Originally Posted by Mike1234
Mike - If you are going to scan, learning about compensating development as a way to simplify your "image capture process" make a lot of sense. In my analysis, it has made shooting film make sense. Here are three information sources that I would suggest...
- Two-Bath Development: Exposure and Development Strategy for Scanning, by Sandy King, published View Camera, July/August 2008.
- Joseph Lipka on Divided D-23
- Search for the term "diafine" at the figitalrevolution.com website, go the last article on the last page of search, and start there. This first of a series of articles on the topic that starts with this article/video: Processing Black and White Film for Scanning – Diafine and TX!
Thank you, Jay.
Changed my recipe for Compensating Pyrocat-MC from 1:20 dilutions to 1:10 dilutions for both Part A and Part B. I have reused the 1 liter of each developer to process three drums of 5 8x10 sheet of film (total of 15 8x10 sheets of film). And, I suspect that I could use it for four drums (total of 20 8x10 sheets of film).
Here's my revised recipe:
Films: Efke 25 exposed at ASA 25 and Ilford FP4+ exposed at ASA 100
Developer: Pyrocat-MC, Part A at 1:10 dilution Part B at 1:10 dilution
Developer and Presoak Temperature: 75 degrees F
Presoak: 5 minutes
Development Times (both films): (5 minute presoak) Part A: 5 minutes and Part B: 5 minutes
Ilford FP4+ @ ASA 100:
EFKE 25 @ ASA 25:
EFKE 25 @ ASA 25:
A question please:
My developer baths got rather cold in my darkroom, like 63 degrees - but I didn't realize it. Watching the development process with my Infra Red monocular, I noticed that after 5 minutes in Solution B, the negative was really under-done. The low values were transparent, even though I placed them on Zone III.
In desperation, I rinsed the negative, and put it back into Solution A for a few minutes, and then back into Solution B. I noticed real improvement in the low values, and no further development in the high values.
Trying to reap additional benefits in the low values, I tried it again - but started to notice overall "fog" or density, so I decided to quit while I was ahead.
Is this a viable technique ?
Last edited by Ken Lee; 24-Jan-2010 at 09:56.
I for one would be elated if your redevelopment technique worked. Have you scanned the negative and confirmed that the highlights did not block-up? If the highlights did not block-up, do you have a plausible theory why they did not, e.g., "tanning" of the gelatin so that further development in the highlights is severely retarded?
The negative is in the wash. I'll let you know.
I made a second shot, but haven't developed it yet. I thought I'd wait and see what the sages have to share
Ken,
I think it is a viable tecnique for those who do development by inspection with IR device.
However, the low temperature will limit how much of Solution A (the reducer) a film can absorb, which is the limit to highlight density. As I would have guessed your rinse and repeat technique increased shadow density somewhat but Solution A appears to have been just too cold to allow good absorption of the reducer. I recommend development at 75 degrees F with divided Pyrocat-HD.
Sandy
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
Thanks ! That makes good sense.
For the record, the film is 5x7 Ilford FP4+.
On the left is a "proof" scan of the 5x7 negative. On the right, cropped, toned, and adjusted a little. (Not the greatest photo in the world, but an exciting scene to encounter and photograph).
The subject contrast was high, and a yellow filter + polarizer was required to bring the sky values to look normal. Shadows are blue, and darken with warm filters.
Pyrocat 2-Bath compensation has definitely come to the rescue. The shadow areas which appear as Zone IV on the left, were Zone II and lower at exposure time. The high values on the distant garage door, fell on Zone IX and higher, but in the negative, they have full texture.
The only problem is a bit of uneven development, apparent in the sky - I presume due to the inadequate absorption of solution A.
Last edited by Ken Lee; 9-Apr-2010 at 08:09.
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