Loris,
A very good description and a starting point for experimentation. I usually keep my bleach concentration on the low side (20cc/liter), but I actually no longer measure the exact amount. Just like a cook adding salt to the dish without measuring how much, I just pour some bleach into the tray. Interesting part of the process is that I had some test strips that I ried to develop overnight and there were still not quite there yet after 12 hours. A 30 second bleach soak followed by 10 minute water development made just perfect test strips.
Marek
Date: Tue, 13 Oct 2009 17:12:29 +0300
From: mail@loris.medici.name
Subject: RE: Miracle size for gum
To: alt-photo-process-l@usask.ca
Bleach development, in short, is developing by adding small amnt. (20-40ml into 1000ml) of household bleach into the development water. It was brought into attention by Marek Matusz a couple of years ago. See my procedure below, I'm sure Marek will describe his and/or add more information later:
* Prepare two development trays, one with bleach and one without.
* Use a generously pigmented coating solution; a pigment amnt. that you would not normally use.
* Expose longer; I use 2x-3x-4x times the normal. (Test!)
* Put the print in the plain water bath to let the unreacted dichromate ooze out, refresh the water few times and drain until the print is clear of dichromate. There will be no (or almost none) development action. Refresh the water again.
* Put the print into the bleach bath and wait for a pre-determined time such as 1-2 minutes. (Test!) The print will start to develop.
* Drain and put the print in the plain water bath, the bleaching action will continue for some time. Check 5-10 minutes later, if the development speed/amount is consistent with the norm (I mean what you experience with normal prints after 10 minutes of development), change the water and continue to develop in plain water. Or, put the print again in the bleach batch to further trigger/speed up development, but keep the bleaching time short this time (15-30 secs), once triggered the development is very quick in the bleach bath.
* Put the print in the plain water bath and continue by bringing back the print to the bleach bath if further more is necessary. You got the idea!
You can use this method to save overexposed layers too - works most of the time. It's my most useful tool in workshop situations, saves time and motivation! :)
Using this method, you can print very dark one-coat prints which have convincing blacks. In other words: "subtlety and drama at the same time"... (See Marek's recent step tablet tests.)
As I said before, I'm sure Marek will add to the information above (or correct it).
Hope this helps,
Loris.
What is blech(?) redevelopment? Do you mean bleach redevelopment?
If it is bleach redevelopment, what do you mean. I have only developed with water.
Thank you, Mary Pat
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