Alkali Fixers - The Myths & Legends

[Lee L]

Agfachrome-Speed. That's it! I don't remember it being for negs. And the use of "chrome" in the name implies slide only.

I only used the reversal material, but PE recalls there being a material for prints from negatives as well: http://www.apug.org/forums/forum40/3...tml#post393244 So I defer to his greater knowledge, being involved directly with the market at the time.

After recalling the name, I found this section of a book on the material: http://books.google.com/books?id=x6N...esult&resnum=4 It doesn't mention an Agfa color process from negatives that equates to Agfachrome-Speed.

And where I used the term 'developer' for Agfachrome-Speed, replace it with 'activator' for accuracy.

Lee

[Photo Engineer]

Yes, my post referred to in Lee's post is correct. The Kodak and Agfa products could work using the same activator which was just concentrated alkali. They both used very similar chemistry, but the Kodak product used a 2 sheet donor and reciever. The Agfa material made a print with a dark back and a normal front image area (actually reversed as seen in the diagram) but the Kodak product made a normal print on normal appearing paper. Kodak material also could make transparencies, but IDK if they ever sold that on the market.

All 3 products, Agfa and Kodak R and C were quite similar in method of functioning.

PE

[Kirk Keyes]

I still believe the Agfa product was for slides only. It had no reciever sheet as the Kodak one did, hence the machine needed for the Kodak and only a tray needed for the Agfa. I have the Darkroom magazine that reviewed this product in 1984 if more clarification is needed. Anyway, we're a bit far from fixer myths or legends!

[Ian Grant]

Have to agree with Kirk, I'm fairly certain it was only ever a Reversal Dye diffusion process and that no negative version was available.

I've got a PDF of the Patents somewhere and also a German PDF data-sheet, but this might ring a few bells





Ian

[Photo Engineer]

I said that in my post. The Kodak product used 2 sheets and made both negative and positive prints, depending on which donor you used. The Agfa material only used 1 sheet which made prints from slides. There were 2 Kodak donors and 1 type of reciever and 1 type of activator. Since it was alkali alone, Agfa could use it.

The Kodak prints were white on the back and had an image on the front. The Agfa product was dark on the front and had an image on the back or support side. The dyes diffused in 2 directions in the Agfa product, out into the activator and inward to the reflective surface. The Kodak product diffused in one direction only, to the reciever sheet.

PE

[billtroop]

But were these color processes archival? I think not. One point of Haist's process was long-term stability; another was cool, blue-black tones, then as now not easy to achieve in a high quality printing paper.

[Photo Engineer]

Bill;

The Ektaflex prints were about the quality of a Ciba/Ilford print, as they used similar Azo dyes. They did have some image smear IIRC due to the low molecular weight of the dyes. IDK about the Agfa product.

The thermally processed materials were surprisingly stable, but Grant ran all of the stability tests, not me, so all I have are his comments and my observations. Some of my processed materials lasted for at least 20 years.

PE