ILFOCHROME HOME-BREWED BLEACH

[AgX]

I found that thread on synthesizing that catalyst:

http://www.apug.org/forums/forum40/3...-recipe-2.html

(starting at post #18)

[Wayne]

Wayne;

There are several different forms of Sodium Thiosulfate. Which did you use? The pentahydrate? In any case was it the powder form or the pellet form? This makes quite a big difference in the final result.

PE

I always used the pentahydrate crystals. I was told by someone with more experience and smarts than I that the amount of hypo wasnt really critical, there just had to be "some" in there. I never experimented with that so I cant say whether it was true.

[Photo Engineer]

The formula as posted in the reference above gives no quantities of ingredients to be used in the bleach. In addition, see my correction to the synthesys. The wrong starting material was specified.

As for the hypo, the amount is critical if one is to prevent loss of dmax and other problems associated with hypo in a developer.

PE

[Wayne]

As for the hypo, the amount is critical if one is to prevent loss of dmax and other problems associated with hypo in a developer.

PE

That could be. I think the person who told me that was a former Ilford chemist but I just took his word for it. I just never worried whether my 1/4 t was a bit over or under.

[brookse]

AgX: Thanks for the thread reference-I remembered page 1, but for some reason did not follow to pages 2&3 ! ....At any rate, I can sympathize with Grweenfields problems:

1) the starting compound "was dark chocolate brown, and so initially were the quinoxalines." 2) "The difficulty was purifying the black oil/paste by re-crystallisation until it was light enough not to risk staining the prints." 3) "The trimethyl derivative is more difficult to recrystallise."

However, I used a different synthetic protocol which easily produces a catalyst which is light "French Vanilla" rather than "Dark Chocolate."

...Also, Sodium Thiosulfate is still on the bottle labels of the P30 developer part A units that I am using for this work.

[brookse]

Hrst in Finland has stepped to the plate! He has already done a nice piece of work with an RA-4 reversal system:

http://www.apug.org/forums/forum40/6...tml#post906230

He will receive formulae and enough catalyst to make 2 L. of bleach. Some of the chromes already used in the above thread will then form the basis of experiments on CLM.1M which is just shy of its expiration date.

Que sera sera

[Ray Rogers]

Interest is now falling off! I would like first to deal with those who are in the US. Certainly Nicholas, and perhaps akaa. I will PM everyone shortly.

Hrst in Finland has stepped to the plate!... He will receive formulae and enough catalyst to make 2 L. of bleach. Que sera sera

Is US focus is now lifted?

[brookse]

Ray.. Originally, the problem for countries other than the US was simply finding a legitimate method of shipping. The international FedX to Hrst required alot of paperwork along with choosing the proper codes for the bleach catalyst. A "no charge" invoice for a "sample" and a "cash value" also have to be indicated. For Hrst, a low $20 cash value was chosen. He will receive the package next week...will any customs be required?...will the chosen codes work?...I don't know right now, but I feel very good about it...and all will be clear shortly. So I think the answer to your question is YES....and there is a good deal of international interest. So just check in again later...especially for Hrst's comments on how things worked in his hands. Of course, some time will be required for all of this...and I assume at least a few problems WILL crop up.... but that's science.

[hrst]

I've got the first results now, and I can say that;

This stuff really seems to work. Brookse has done good work. I have perfect black and white, vibrant colors and only little crossover, and quite easily.

There is only a very tiny bit of silver for blix to remove after the dye bleach and fixer.

The very first test sheet was great. No problems arised yet.

I'll continue to work with this and report when I have more specific results.

I'm working with trays.

[hrst]

CLM 1K. My first tests with home-brew developer and bleach. Agefix 1+5 as fix and then RA-4 blix. There was a bit of visible silver in the campfire picture in the flame before blix.

Scanning is a bit problematic as always, because that super-glossy feeling is missing. I ended up to make raw scans first and then do exactly the same level corrections to every scan, so you really can compare the relative densities. The first one is without hypo in developer. Scanning exaggerates the difference somewhat.

Step wedge steps are 0.15 (half stop).