[Alt-photo] Dichromate Poisoning

Jim Patterson jimbobnola at cox.net
Tue Oct 31 16:11:45 UTC 2017


Yes, GB is gum Bichromate.  For GB alternates I use Cerium IV Ammonium Sulfate and your Ammonium Citrate, dibasic.  For the coating on waxy corn starch, I use CAN.  Google “Cerium 
waxy corn starch”.  CAN should work for both.  I just have a kilo of each left over from a medical school project.
Jim

Sent from my iPhone

> On Oct 31, 2017, at 9:05 AM, Richard Sullivan <sullivan8486 at gmail.com> wrote:
> 
> Jim,
> 
> This is all fascinating and I want to give it a try.
> 
> One thing: What is GB? (I am at the age when I learn something new I have to forget something old and I may have forgotten what GB is. Gum Bichromate?)
> 
> You've listed a lot of possibilities but what do you consider the optimum place to start?
> ? Cerium IV Ammonium Nitrate?
> 
> --Dick Sullivan
> 
> 
>> On Mon, Oct 30, 2017 at 3:09 PM, Jim Patterson <jimbobnola at cox.net> wrote:
>> Correction:  polyethylene glycol diacrylate
>> 
>> Sent from my iPhone
>> 
>> > On Oct 30, 2017, at 11:17 AM, Kelcy Patterson via Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org> wrote:
>> >
>> > Hi Richard and Larry,
>> >
>> > Cerium iii Chloride hardens gelatin moderately, and Cerium iv Ammonium Nitrate hardens gelatin strongly.  I reconfirmed that yesterday by coating a 5% solution of each on a strip of B&S carbon tissue, then soaking it in warm water.  The cerium iii was hardened down to the base.  The cerium iv was very hard, like when you over expose a dichromate carbon tissue.  I tried Cerium iv Ammonium Sulfate dihydrate, complexed with Ammonium Citrate, dibasic  (1:2 by wt) with a CAS concentration of 5% and AC 10% solution on a strip of carbon tissue.  I then exposed it to UV with a strip of black paper down the middle.  I was surprised to find that the unexposed area was hardened, and the exposed area dissolved away.  ? possible to do a direct positive process.  I will work on that later.  I did develop a type of carbon process by coating paper sized with waxy corn starch, coating with CAN in very dilute nitiric acid, drying, exposing the paper through a positive to UV, then soaking the C tissue in 2% oxalic acid, mating, developing as usual.
>> >
>> > The most relevent sources I used for GB alternates were the following:  Google these:  Polymerization system using Ceric salts, Photoinitiation cerium iii sulfite, Eosin Y photopolymer.  These processes are free radical polymerization.  I have avoided Acrylic Acid as it is toxic and carcinogenic.  I have used as binding polymers: gelatin, fish glue, PVP, PVAl, methyl cellulose, and gum Arabic.  I have used as monomers and crosslinkers:  polyethylene diacrylate, 400; N-vinyl pyrrolidone; N,N-methylenebisacrylamide, and diacetone acrylamide.  My best results are with PVP K60, NVP, and MBA.  I am planning to post a print soon and you can judge if it is worthwhile.  Note that the Eosin Y is sensitive to green light, not UV, so you can use a bright LED light or sunlight.
>> >
>> > Jim Patterson, New Orleans
>> >
>> >
>> >
>> > On October 27, 2017 at 4:15 PM Richard Sullivan <sullivan8486 at gmail.com> wrote:
>> >
>> >
>> > From CameraCraft 1929 pg 593
>> > The OCR scan is a bit weird!
>> >
>> > The Carbon Process
>> > Dr. E. J. Tritton recently read before
>> > the Royal Photographic Society (G. B.)
>> > an exhaustive and rather technical paper
>> > on methods of increasing the printing
>> > speed of bichromated gelatine, inasmuch
>> > as this includes the printing of carbon
>> > tissue and the carbon process still holds
>> > an important place in professional portrait photography, its practical application will interest carbon workers.
>> > "If a small quantity of a cerium salt
>> > for example cerous chloride is added
>> > to the usual dichromate bath, the speed
>> > of the resulting carbon tissue is considerably increased, while the subsequent
>> > development, and other operations remain
>> > exactly as usual. A suitable formula for
>> > a sensitizing bath is:
>> > Pot. dichromate pure cryst 2% parts
>> > Cerous chloride 10% sol 2 parts
>> > Water 100' parts
>> > "It is most important to note that only
>> > pure dichromate should be used, and no
>> > ammonia must be added tc it.
>> > "The disadvantage of this process is that
>> > it does not keep well. A much better
>> > method is to sensitize the tissue in plain
>> > dichromate, e. g., the above formula with
>> > the cerous chloride omitted, and then to
>> > give only one-third of the exposure that
>> > would be required under normal circumstances.
>> > "For mounting, instead of soaking the
>> > tissue the normal way in water, a 2%%
>> > solution of cerous chloride is used. When
>> > the tissue is limp to the correct extent in
>> > this solution it is mounted on the soaked
>> > transfer paper in the normal way, left between blotting boards 15 minutes, and then
>> > developed in hot water. A full strength
>> > image is then attained without any other
>> > variations in the process. The time of
>> > soaking the tissue in the cerous chloride
>> > solution has practically no inlluence on
>> > the density or gradation Of tin- image obtained, and neither is the exact concentration of tin- Quid of great importance, but
>> > with both very weak and very strong solutions, such as 1% to 4'/t, there is a tendency to flatness. The cerous chloride solution can be used over and over again,
>> > and also a used solution can be stored and
>> > then used again, despite the fact that it
>> > gathers dichromate from the sensitive tissue, after a time however the resulting
>> > prints are found to be slightly flatter.
>> > "Obviously by employing this procedure
>> > the normal keeping qualities of the tissue
>> > are retained, but it is equally obvious that
>> > any tint or fog that may be on stale tissue
>> > will be just as much intensified as the
>> > exposed image. Hence only fresh tissue
>> > should be employed."
>> >
>> >> On Fri, Oct 27, 2017 at 1:19 PM, Larry Ogrodnek via Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org mailto:alt-photo-process-list at lists.altphotolist.org > wrote:
>> >>
>> >> Hi Jim,
>> >>
>> >>    I'm interested to learn more about these alternative sensitizers -- do you
>> >>    have any text/links/reference you could send on their use?
>> >>
>> >>
>> >>    thanks!
>> >>    larry
>> >>
>> >>    On Thu, Oct 26, 2017 at 10:42 AM, Jim Patterson via Alt-photo-process-list <
>> >>    alt-photo-process-list at lists.altphotolist.org mailto:alt-photo-process-list at lists.altphotolist.org > wrote:
>> >>
>> >>> Hi All,
>> >>> Being an occupational physician I am aware of the risks of Chromium VI.
>> >>> On the certification exams they always have questions on chrome holes,
>> >>> perforated nasal septum, and nasopharyngeal and sinus cancer.
>> >>>
>> >>> I have been a student of Chris and she preaches safe handling and personal
>> >>> protective equipment.
>> >>>
>> >>> In the past 2 yrs I have been experimenting with alternate Sensitizers and
>> >>> colloids.  The most promising at the moment are Cerium IV Ammonium Sulfate
>> >>> and Eosin Y.
>> >>>
>> >>> Both of these harden gum Arabic, gelatin, fish glue, cellulose gum, PVP
>> >>> and others.  I am not saying they are better than GB, but are alternatives.
>> >>>
>> >>> Jim Patterson, New Orleans
>> >>>
>> >>> Sent from my iPhone
>> >>>
>> >>>> On Oct 26, 2017, at 2:12 AM, Charles Berger via Alt-photo-process-list <
>> >>> alt-photo-process-list at lists.altphotolist.org mailto:alt-photo-process-list at lists.altphotolist.org > wrote:
>> >>>>
>> >>>> My post was prompted by the declaration of a highly regarded arts
>> >>>> educator/author that if/when dichromate was restricted here, as it is in
>> >>>> the EU, she had a sufficient supply for her and her students to continue
>> >>>> using it indefinitely.
>> >>>>
>> >>>> This cavalier attitude towards the use of dichromate for the sake of
>> >>>> photographic printmaking is ill advised as it implies that the dangers
>> >>> are
>> >>>> not to be taken seriously.
>> >>>>
>> >>>> Responses ranged (with a few exceptions) from the abusive (and idiotic)
>> >>>> advise not to “lick the top of Cherry wood table” to a non-sequitur
>> >>>> description of the installation of seat belts in a 1956 Oldsmobile.
>> >>>>
>> >>>> The point I was making is that there is little discussion of dichromate
>> >>>> poisoning and a lack of detailed information (beyond “wear gloves”) on
>> >>> its
>> >>>> safe use in the current literature on alternative photo processes.
>> >>> Perhaps
>> >>>> Marton was correct when he wrote about “The Dichromate Disease” in The
>> >>> *Photo
>> >>>> Oleograph Process*(1900) that “Rich living and alcoholic stimulants, seem
>> >>>> to foster this peculiar ailment”,  and thus all we need to do is avoid
>> >>> such
>> >>>> behaviors to safely work with dichromate.
>> >>>>
>> >>>> Why are so many of you upset about discussing this? And why do you feel
>> >>>> compelled to defend this lack of concern and to dismiss any in-depth
>> >>>> information on the subject as “scare tactics?”
>> >>>>
>> >>>> Full disclosure:  I have recently been exploring with Chris the creation
>> >>> of
>> >>>> a book (or series of books) describing non-toxic alternatives to historic
>> >>>> photographic printmaking. Her statement caught me completely by
>> >>> surprise. I
>> >>>> am confident that Chris is truly concerned with the health and safety of
>> >>> us
>> >>>> all, but this dismissive attitude is unfortunate.
>> >>>>
>> >>>> Charles
>> >>>> _______________________________________________
>> >>>> Alt-photo-process-list |http://altphotolist.org
>> >>>
>> >>> _______________________________________________
>> >>> Alt-photo-process-list |http://altphotolist.org
>> >>>
>> >>    _______________________________________________
>> >>    Alt-photo-process-list |http://altphotolist.org
>> >>
>> > _______________________________________________
>> > Alt-photo-process-list | altphotolist.org
>> 
> 


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