Hydroquinone is a carcinogenic skin whitener???

[skahde]

In extensive tests by Kodak, HQ and Metol and several color developing agents (CD-3, CD-4 and CD-6) were found to be low in toxicity as they are not absorbed through the skin to any great extent.

Unfortunately hydroquinone is also readily absorbed through the skin.

I hope Gordon Hutchings is doing fine and I will take this as good enough evidence that one can use pyro as well as hydroquinone on a regular basis and stay healthy as long as you take enough care.

best

Stefan

 

[Ian Grant]

Stefan, can you not read Hydroquinone is not readily absorbed through the skin, as Ron (PE) says and also the information I posted. HQ is relatively harmless, Pyrogallol positively dangerous by absorption.

Ian

 

[Photo Engineer]

I have to agree 100% with Ian! (and Gordon Hutchings and A&T and Kodak's medical department and many published reports)

PE

 

[john_s]

On the subject of Anchell and Troop's level of warning on chemicals, I have collected some posts by Bill Troop about the VMI mercury intensifier because a have a set of negatives that would benefit from that type of intensification. In his posts, he warns that mercuric chloride is "caustic" and needs to he handled with care.

Now, as much as I very much admire the author's work and efforts to be helpful, I find it extraordinary that he should not issue warnings about the danger of mercury compounds and the need to dispose of them responsibly. I get the impression that he feels very competent in his own use of such chemicals (as do I), but he is remiss in not being more thorough at least in this case.

On the subject of hydroquinone, at least it degrades in the environment, and is safe enough to be used with normal precautions.

 

[Photo Engineer]

I know that Bill is very aware environmentally. I think perhaps that since the problems with mercury are so well known that he may have not gone into any detail compared with his comments about pyro for example.

In any event, you cannot be all things to all people.

PE

 

[billtroop]

John, wherever you got those posts from, they were not from me. I have found a post from you here

http://www.freelists.org/archives/pure-silver/06-2006/msg00286.html

which I do not recognize as anything I have ever written. Could you possibly have got this material from my co-author Steve Anchell? Wherever you got it from, I don't think much of it.

Regarding Pyrogallol and toxicity, I really think Gordon Hutchings is the expert on this; I trust his asseveration that the chemical is unusually dangerous -- certainly more so than HQ. To take an MSDS as a literal statement of established scientific truth is ridiculous. They are often contradictory or have a commercial agenda. Gordon is not a scientist but he has done a good three decades of careful research on this chemical. I don't think the observations in his book are fanciful. Just my opinion.

Thanks, Ron, for looking out for my back! Greetings and best wishes to everyone !

C

On the subject of Anchell and Troop's level of warning on chemicals, I have collected some posts by Bill Troop about the VMI mercury intensifier because a have a set of negatives that would benefit from that type of intensification. In his posts, he warns that mercuric chloride is "caustic" and needs to he handled with care.

Now, as much as I very much admire the author's work and efforts to be helpful, I find it extraordinary that he should not issue warnings about the danger of mercury compounds and the need to dispose of them responsibly. I get the impression that he feels very competent in his own use of such chemicals (as do I), but he is remiss in not being more thorough at least in this case.

On the subject of hydroquinone, at least it degrades in the environment, and is safe enough to be used with normal precautions.

 

[billtroop]

PS: Don't use mercury without exceptional protection!!! Arnold Newman told me it was the one chemical he wouldn't let his assistants use. He thought it too dangerous, he didn't want the responsibility of harming them. So on the rare occasions he's had to use it, he did it himself. What a guy!

 

[Photo Engineer]

I'll revise my list of toxicity to include Pyro, Selenium, Mercury and Cadmium not necessarily in that order. They are all nasty!

I agree with Bill, mercury is not to be trifled with. As part of a large team at Kodak, we worked hard to eliminate Mercury and Cadmium from films and papers. I was on the color paper team. We also virtually eliminated Mercury. A tiny amount of mercury remained in one layer of color paper.

PE

 

[john_s]

Apologies to Bill Troop

Bill, I have done you an injustice and I apologise. The notes that I had were in a clipboard of various notes which I had collected that expand on the contents of "The Film Developing Cookbook" and which I had entitled "Anchell and Troop" and the article was in fact by Steve Anchell. I am really sorry that I was so careless. The web address of that article is:

http://www.rangefindermag.com/magaz...eference=42C9284B46EB3754B860D8A3BA7546E6380E

So again, please accept my apologies, and I take the point made by PE that everyone knows how dangerous mercury is, and would act accordingly.

John Stockdale

 

[billtroop]

Thanks very much, John! You really had me worried for a minute there. I was thinking -- could I have lost my mind and actually written that stuff about mercury? Steve is the greatest co-author ever, but -- let's put it this way: I accept full responsibility for every syllable in the Film Developing Cookbook. I don't accept any responsibility for anything Steve has written on his own. With regard to the general issue of carcinogenicity, as we all know, there would be few women left on Earth if the photographic chemicals commonly used in hair dyes were all that carcinogenic. Somehow, in over a century of use, there seems to be little decisive linkage. With regard to pyro, the chemical, throughout most of the 20th century, was used so many orders of magnitude less than HQ that the medical evidence (and the need to acquire it) simply isn't there. I know Steve believes that careless pyro use was responsible for health problems with the Weston men; that hasn't been medically established; it's anecdotal opinion. But there is a lot of anecdotal opinion out there. A lot. Since we will never know just how dangerous pyro really is (because it will never be used enough to warrant the research), it seems to me prudent to treat it with extra care. What's the harm in spending a few more minutes in the darkroom making sure you minimize your exposure to chemicals? The darkroom is a serious place; it's not a playpen.

Apologies to Bill Troop

Bill, I have done you an injustice and I apologise. The notes that I had were in a clipboard of various notes which I had collected that expand on the contents of "The Film Developing Cookbook" and which I had entitled "Anchell and Troop" and the article was in fact by Steve Anchell. I am really sorry that I was so careless. The web address of that article is:

http://www.rangefindermag.com/magaz...eference=42C9284B46EB3754B860D8A3BA7546E6380E

So again, please accept my apologies, and I take the point made by PE that everyone knows how dangerous mercury is, and would act accordingly.

John Stockdale