Hello everyone - I've been shooting plates (ambros) in the field lately (I usually just stay around my "darkroom") and am having an issue with them darkening due to incomplete washing. I know the solution would be to wash them in the field, but water quantity is an problem. I had been placing them (after removing them from the fix (cyanide)) in a tray of water out of direct sunlight (usually under my car) until I could bring them home for a more complete wash. But within an hour they darken considerably. Do people use "light-tight" trays, or wash plates adequately in the field? Thanks.

I've never heard of this happening with cyanide fixed plates except for unkept and/or unvarnished plates over a long period of time. Could you post a digital pic of an example, or a scan of one?

KCN washes off quickly, which is the main advantage for using it in the field over sodium thiosulfate. A cup of water is usually sufficient for me to wash my plates after fixing.

Sample pics would help...

A cup of water ? That's interesting as well as good news ,since I normally use about 2 - 3 quarts per 8x10 plate.

Are you processing in warm temps?


I have had the same problem. Much or all of the image would darken after fixing in cyanide. It seemed to be connected to the heat. I started cooling down my chemicals, (first just the developer, then the silver bath and fixer) and the darkening ended.
Most of the time, the darkening was accompanied by a purplish-blue tint (not the blue that appears on the thick pour-off edges).


Then I had "holes" of undeveloped areas, so I remedied that problem by adding alcohol to my sugar developer (I was using the Coffer formula that calls for no alcohol).

The temperatures (air and chemical) haven't been too warm (I'm up in Maine). The other interesting thing (maybe just coincidence) is that the darkening only happened with the black and purple glass, not clear glass.

Perhaps there is something on the glass thats causing this...how are you cleaning it?

davidjohnlotto Wrote:
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> A cup of water ? That's interesting as well as
> good news ,since I normally use about 2 - 3 quarts
> per 8x10 plate.

Yes, I use about a cup of wash water after fixing (with cyanide) for a half plate up to 5x7 size...what I do is setup a 3 tray system in my darkbox. Tray 1 is my developer tray, tray 2 is wash #1, and tray 3 is wash #2. They are 5x7 trays and I put enough water in them to be about 1/2 inch deep. I come out the darkroom with tray #3 after developing, dump the water, toss the plate in about 1/2 a cup of water, dump, another 1/2 cup rinse, dump, fix, 1/2 cup rinse, dump, 1/2 cup rinse. I then either put the plate on my drying rack, or I dry it over a lamp and varnish it. For the next plate, I move tray #2 to tray #3 position and reuse the water in that tray. Been working good for me, and I'm carrying a lot less water with me now. Seven gallons seems to be plenty for a semi-active day a shooting.


Hope that helps!

If it isnt happening with clear glass I would suspect something besides the fix. It doesnt take a lot to wash cyanide from your plate.

If you dont have enough water for any reason, consider using a 50/50 mix of glycerin and water as a preservative in the field. AS for the sunlight....restrict this as much as possible. After you have developed the plate, do a little rinse, flow the plate with the glycerin/water combo and put it FACE up in a lightproof box. When you get back to your darkroom, wash off the glycerine with a gentle stream of water, and fix and wash as normal.

If you have any sort of ability to make things, picture a side loading slotted box made from wood or black plastic or something lightproof. Place the glycerin coated plates in there and shut the lid.

Also a note on "trays". Hypo in particular is heavier than water. Setting a plate flat in a tray of water, with no agitation or angle to let the residues "slide" off...well, where will the hypo go? When you rinse, pour the water on at an angle, and fling it off after you pool it on. The only real safe and easy way to rinse in a static mode would be to lean the plate up against the side of a bucket of water (with the plate in the bucket).



Edited 1 time(s). Last edit at 09/13/2007 02:50PM by Ray Morgenweck.

Ray is right,In the field I always set the plate on end in the wash bucket and give it a shish every few minuets. After about ten minuets I set it in another bucket of clean water and do the same thing then give it a rinse befor drying.

My plates are 11x14". After a KCn fix, I give them three rinses in water (jugs, puddles, even salt water in a pinch) -- just a couple of splashes from by jug. I then coat with the aforementioned glycerine and water. At home that get a 5 minute wash and a final rinse in distilled water. No problems with darkening.

Your description sounds like either exhausted fixer (avoid sun and heat - mix KCn fresh for each days shooting, 750 ml should easily fix 1900 square inches of plates) or a problem with the plate material.

You mention that "the darkening only happened with the black and purple glass, not clear glass". If clear glass is ok then its pretty surely not your chemistry. Try a tin or a different maker of dark glass to confirm that there's "something" on the glass you are using that causes issues. That, and check you glass cleaning procedures.

NWG

Ray, I agree that hypo is heavier/has a higher specific gravity than water, but when mixed with water I can't see that the hypo sinks to the bottom (unless the hypo:water ratio is so high that the water is super-saturated with fixer salts and drops what cannot be dissolved, or when you first add a thick syrupy fixer concentrate to water - it becomes a homogeneous solution after mixing).

Even if left perfectly still for an age, there is a molecular activity called "brownian motion" in liquids and gases that ensures motion. One fellow let a solution of fixer/water sit on a shelf for a year in the lab where he worked. then had them sample the solution at the top and at the bottom - no difference.

Fixer leaches out of film emulsion - so agitation ensures that it leaches out more rapidly. It cannot slide or fall off, it diffuses out producing a gradient in the concentration.

I think this myth (which plenty of people believe) was propagated by Fred Picker and the Zone VI print washers that he sold and promoted.

Regards,
Neil.

buckp74 Wrote:
-------
> thing (maybe just coincidence) is that the
> darkening only happened with the black and purple
> glass, not clear glass.

This phenomenom (sp) has been observed by myself with the same two colors of glass. Now, I have noticed over the years of buying this colored glass that there was an oil looking type film on the darker colored glass from a certain manufacturer. NO MATTER what I did to clean the glass it still seemed to extrud this "oil". Because of that the images I did on the colored glass seemed to be much darker and seemed to get darker after processing than my "tins" or clear glass. I have switched brands of glass and no longer use the black glass and I have not had a problem since. I believe there was a chemical reaction with the glass and my chemistry so I stopped using it. That is my opinion.
Thanks,Wayne

Wayne L. Pierce
[companyphotographer.com]

Hey everybody - thanks for all the replies and suggestions. I started thinking my fix (cyanide) was semi-exhausted, and my wash was inadequate. So I mixed new fix, after fixing dunked the plates a few times in a bucket of water, and then placed them in a tray of water with a cover, and viola - no more darkening of plates. Thanks again everyone.