Antifog -- Potassium Iodide? If so, how much?

[Donald Qualls]

I've just tried some 55+ year old contact printing papers that came to me in a darkroom kit I bought a couple years ago (for the 620 spools, but I'm using most of the contents now).

I have a nearly full box, looks like 100 sheets (2 1/2 x 3 1/2), of Ansco Convira which, though very, very slow, shows almost no fog -- slow, as in fifteen seconds under room light (75 W bulb, diffused, 6 feet distance), contacting under a normal negative, is about two stops too little! I also have what looks like 20 or 30 sheets of Kodak Velox, on which I found an expiration date of Feb 1951; it's a couple stops faster than the Convira, but in my Dektol 1+4 is fogged to about Value 8 -- quite visibly gray.

I've heard of using potassium bromide as a restrainer, as well as benzotriazole. I don't have either one, and lack budget to buy chemicals right now, but I do have a small bottle of potassium iodide -- am I correct in understanding it is a much stronger restrainer than the bromide? If so, how much would be a good starting point to add to Dektol for use with this fogged Velox?

 

[Ryuji]

Iodide can function as a restrainer or an antirestrainer depending on the concentration, emulsion and developer. I don't recommend using iodide for your application. Also, if your paper is fogged that much, I am afraid to say no developer additive would restore useful funcion of the paper. Adding a lot of antifoggant would only require longer development time to obtain good image density, at which point fog will return.

 

[Keith Tapscott.]

I've just tried some 55+ year old contact printing papers that came to me in a darkroom kit I bought a couple years ago (for the 620 spools, but I'm using most of the contents now).

I have a nearly full box, looks like 100 sheets (2 1/2 x 3 1/2), of Ansco Convira which, though very, very slow, shows almost no fog -- slow, as in fifteen seconds under room light (75 W bulb, diffused, 6 feet distance), contacting under a normal negative, is about two stops too little! I also have what looks like 20 or 30 sheets of Kodak Velox, on which I found an expiration date of Feb 1951; it's a couple stops faster than the Convira, but in my Dektol 1+4 is fogged to about Value 8 -- quite visibly gray.

I've heard of using potassium bromide as a restrainer, as well as benzotriazole. I don't have either one, and lack budget to buy chemicals right now, but I do have a small bottle of potassium iodide -- am I correct in understanding it is a much stronger restrainer than the bromide? If so, how much would be a good starting point to add to Dektol for use with this fogged Velox?

Throw it away.

 

[eumenius]

Dear Donald,

I am routinely using ID-62 1+3 as a primary paper developer, it's quite convenient, gives good tones on all papers available to me, and it's cheap - I mix it by myself. It never gave me fog even on older Russian papers, notorious for their unstability. The formula contains benzotriazole, that explains why the fog level is always low. Maybe a small bottle of benzotriazole is worth investing, eh? It's always easier and nicer to be independent of your BW chemistry manufacturer, anyway.

Regards from Moscow,
Zhenya

 

[David A. Goldfarb]

Old slow contact papers hold up surprisingly well, and a restrainer can help, but you might also try increasing exposure and reducing development time. If you're using Dektol, I'd be diluting it 1+2, rather than 1+4, and trying for a development time of less than 1 min., if you're getting noticable fog. Maybe get it down to 45 sec., and then try a restrainer like Edwal Liquid Orthazite or benzotriazole.

One might ask why this is worth doing. Old contact papers often have an interesting rich tonality. If you can make them work, the visual results might convince you that they are worth the effort.

 

[Rlibersky]

One might ask why this is worth doing. Old contact papers often have an interesting rich tonality. If you can make them work, the visual results might convince you that they are worth the effort.

I agree. Even some enlarging papers from the past are worth an effort.

 

[Donald Qualls]

Well, the other reason it's worth doing is just for the pleasure of trying it. It's been about 35 years since I've seen extensive contact prints from 120/620 film, and I'm starting to remember why I liked them -- they were what made a $2 box camera look as good as Granddad's old Kodak Tourist II, until you asked for an 8x10 to frame. Yeah, sure, I can cut down any graded paper and get something similar, and no, I'm not sure I know (yet) what anyone actually means by "interesting rich tonality" -- I'm still relearning what I knew about printing when Polycontrast II was a new product and you could still buy Velox new.

Like many of the things I do with my photography, in part, I'm doing it because I have the stuff to proceed without spending more money, and it's fun. Now, if I could hold the stuff flat, it would help a lot -- but that just calls for using a contact printing frame (which I have) and spending the time to figure how to load the stuff in so it stays stacked straight.

 

[Donald Qualls]

Throw it away.

Thank you, Mr. Naysayer.

Some of us don't have money to throw at photography, but do have (at least some) time to spend on it, and a modest store of materials and chemicals. We try to make do with what we have, and if, with some effort, we can get results, that's great -- if not, we haven't wasted time we should have used to make a living (because we aren't making a living with this anyway), but only spent pleasurable hours in the darkroom, and perhaps learned something useful (like I learned, a couple days ago, just how far one can push TXT).

If it's frustrating and obviously useless, I'll toss it like a bad enlargement. Until then, I'll experiment -- and little lost either way.

 

[Donald Qualls]

Also, if your paper is fogged that much, I am afraid to say no developer additive would restore useful funcion of the paper. Adding a lot of antifoggant would only require longer development time to obtain good image density, at which point fog will return.

This is more or less what I suspected, but there are still things I can try -- for one, the other suggestion to increase exposure and reduce development; for another, I do have what I need to make a simple bleach, and if I can make a cutting bleach, I might be able to clean up the borders and highlights without reducing the shadows noticeably. If bleaching these little prints will make the paper useful, then I'll have learned something that may be of use another day -- and the same if not.