chromium intensifier
br
"blah" using fiber base paper. The result is a strange yellow color that did
intensify the image and seemed to improve the image somewhat.
Any thoughts on this?
Bill
Gene A. Townsend
Yes, my thoughts are blah, blah, blah. :-)
So you intensified the image on the print? That's a bad practice.
Chromium intensifier is very dangerous, I would stay away from that.
Prints toned that way will not be permanent. Use selenium toner, much
better results. This intensifier was used in the old days with film
only. I used to use "Victor Intensifier" regularly in the 60's, a
chromium intensifier. All those negatives have faded into oblivion,
even though they were stored in the dark. The active ingedient was
mercuric chloride, one of the most dangerous chemicals out there.
GAT
>
>Bill
>
>
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Tom Reinhardt
rarely and always with less than stellar results, on negatives ... and only as a
last resort. Interestingly enough, and I'm sure that some on this list will
have the "missing details," I recall using a dichromate bleach/redevelop process
to alter the contrast of prints ... that was something called "Sterry's
Method(?)" --any historians out there? If I remember correctly, I'd give the
print several times the normal exposure, immerse it in this dichromate bath,
then dektol (or whatever), stop and fix. Oh, and if I remember correctly,
dichromate is deadly stuff.
So, why are you doing this?
TomR
Richard Knoppow
>On Mon, 05 Aug 2002 12:00:44 GMT, "br" <b...@t-one.net> wrote:
>
>>I tried chromium intensifier on a test strip of an image that was rather
>>"blah" using fiber base paper. The result is a strange yellow color that did
>>intensify the image and seemed to improve the image somewhat.
>>
>>Any thoughts on this?
>
>Yes, my thoughts are blah, blah, blah. :-)
>
>So you intensified the image on the print? That's a bad practice.
>Chromium intensifier is very dangerous, I would stay away from that.
>Prints toned that way will not be permanent. Use selenium toner, much
>better results. This intensifier was used in the old days with film
>only. I used to use "Victor Intensifier" regularly in the 60's, a
>chromium intensifier. All those negatives have faded into oblivion,
>even though they were stored in the dark. The active ingedient was
>mercuric chloride, one of the most dangerous chemicals out there.
>
>
>
>GAT
>>
>>Bill
>>
Victor intensifier is a Mercuric chloride intensifier, NOT a Chrome
intensifier. Chrome intensifier employs Potassium Dichromate. While
dichromates should be used with care they are far from being as toxic
as mercury compounds. Dichromate's main dangers are that it is a
carcinogen and can cause very severe burns in a concentrated state.
The intensifier solution is moderately hazardous and contact with
the skin should be avoided.
Kodak packaged Chromium intensifier until a few years ago. They
stopped because Chromium compounds are considered environmental
polutants.
Chromium intensifier is a bleach consisting of Potassium Dichromate
and hydrochloric acid.
The main problem with using it on prints is that the image is not
permanent.
---
Richard Knoppow
Los Angeles, CA, USA.
dick...@ix.netcom.com
Richard Knoppow
Chromium intensifier is a bleach using Potassium Dichromate and
Hydrochloric acid. It leaves a yellow or orange stain.
You might try clearing the stain in a bath of 5% sodium sulfite or
potassium metabisulfite, used after the intensifier and before
redevelopment. The negatives or prints should be washed after the
clearing bath.
The image from Chromium intensifier is not completely permanent.
A silver intensifier, like Kodak In-5 is more satisfactory for
prints. Its rather more complicated than chromium intensifier. I'll
post the formula if anyone wants (lots of typing).
Beware than Potassium Dichromate should be handled with care. It can
cause serious skin burns which heal slowly when concentrated.
Hydrochloric acid is also hazardous. The mixed bleach is diluted
enough not to be dangerous but should still be handled with gloves.
The Dichromates are considered carcinogens.
Also, try intensifying with Kodak Rapid Selenium Toner. It increases
the shadow contrast with minimal effect on image color and is low
hazard.
Francis A. Miniter
You really, really have to wash the bleached print until all trace of the bleach
is gone. It can even take 1/2 an hour.
Francis A. Miniter
br
This was done as an experiment on a "test strip" and not on a final print
and like I said a very strange yellow that did intensify the image.
Even using selenium we need to be careful to keep it away from acids. If in
contact with an acid the vapors created can become quite caustic. Accidents
can happen.
Perhaps more discussion on darkroom safety is called for.
Bill
"Francis A. Miniter" <min...@attglobal.net> wrote in message
news:3D4EE91D...@attglobal.net...
brookmartin
Dear Richard,
Please, please, please, please, please, please.........
Thank You!
Brook
> The image from Chromium intensifier is not completely permanent.
> A silver intensifier, like Kodak In-5 is more satisfactory for
> prints. Its rather more complicated than chromium intensifier. I'll
> post the formula if anyone wants (lots of typing).
>