PDA

View Full Version : Hardening fixer formula



Asarnil
08-29-2010, 02:49 PM
Hello all!
After a vacation break I plan to get back to work on my emulsions and I was browsing Denise's page (which is an awsome help to any gelatin newbie :)) and I found Kevin Klein's emulsion formula which seemed to me pretty nice and worth of trying (especially that the examples of pictures used in the article are more or less what I'm aiming to).
After reading, giving it some thoughts and doing some research I have not managed to find any hardening fixer formulae (which is used in Kevin's recipe). I suppose it is some kind of a mix of Hypo fixer and chrome alume...
Normally I would buy one but it's very hard to get here and brewing some for myself seems more "appropriate" to gelatin emulsion ;).
Anywho, if any of you guys have any formula to share (and maybe some tips how to use it properly), it would be awesome.
Thanks and cheers!
A.

Photo Engineer
08-29-2010, 03:26 PM
Use Kodak's F-5 formula. I believe that it is a hardening fix. There is also one in Anchell and Troop IIRC. If you cannot find one with these references, let us know. I'm sure I can find them.

PE

willrea
08-29-2010, 03:35 PM
F-5 Hardening Fixer

Water at 125F (52C) - 2500ml
Sodium Thiosulfate - 960g
Sodium Sulfite - 60g
Acetic Acid, 28% - 190ml
Boric Acid - 30g
Potassium Alum - 60g
Cold water to make 4000ml

This is according to Natural Color Processes by Carlton Dunn

Photo Engineer
08-29-2010, 03:40 PM
It is posted here in the articles section on fixers!

PE

Asarnil
08-29-2010, 03:50 PM
Thanks guys, I'll try it as soon as i'll get back from the vacation.
cheers!
A.

Anon Ymous
08-29-2010, 04:29 PM
I haven't used F5, but it is said that it smells quite a bit (sulfur dioxide). F6 is almost odourless and it's formula can be found, among others, in Kodak's technical publication J1 (http://www.bonavolta.ch/hobby/files/Kodak%20j-1.pdf) (page 38).

Photo Engineer
08-29-2010, 04:39 PM
F6 does not harden as well as F5 or F7 due to the higher pH. The Alum is less effective as pH goes up.

PE

Robert Budding
08-30-2010, 09:53 AM
Which formulation does Kodak sell as Rapid Fixer?

Photo Engineer
08-30-2010, 10:57 AM
Rapid Fixer with Hardener is close to F-5 using Ammonium Hypo and being adjusted to a pH of about 4.5 or 5.

PE

dwross
08-30-2010, 12:54 PM
Hi Asarnil!

Nice to hear from you again. I hope you're having a great vacation. I certainly approve of your vacation reading material :D.

When I started making dry plate negatives, I just carried over the basic processing techniques I'd used for years with commercial film negatives -- most recently Heico fix with half the recommended hardening additive. Works fine, but if you are interested in pursuing as historical a path as possible, you might follow the advice of T. Thorne Baker in Successful Negative Making, 1905. Baker wrote it as a short manual for using the newly available commercial gelatin dry plates. He writes,
"The quantity of hypo used in the fixing bath varies according to the make of the plate used, but in general a solution of:

Hypo ..... 5 oz
Water .. 20 oz

will be found to answer well. Some makes of plates contain a larger percentage of silver iodide than others, and these require a very strong bath, such as eight ounces of hypo to the pint of water." p33.

And on p35, "In hot weather it is sometimes necessary to employ a hardening bath, in order to prevent frilling at the edges of the film. Alum, chrome alum, or formalin are the recognized agents for hardening, and they are of power increasing in the order named. Thus a five percent solution of alum may be used, a one per cent solution of chrome alum, or a very weak solution of formalin. Blistering is most frequently caused by transferring a plate from a warmish developer to a freshly-made and therefore very cold fixing bath; it is essential to avoid sudden temperature changes when dealing with gelatin."

I don't know if you have any trouble getting chrome alum, but plain (potassium) alum should be readily available as a home canning supply. It's no longer recommended as such because of health concerns, but a lot of home preservers still use it and it's very inexpensive -- at least in my area.

Looking forward to seeing more gorgeous plates!
d

Asarnil
08-30-2010, 03:07 PM
Hey guys,
even that I'm oficially at the vacation I couldn't resist to take a quick look at what you wrote ;). Denise - what you have written is actually very, very helpfull because i found a small detail that certainly had an influence on the gelatin and caused frilling on the edges and making the surface of the whole plate "fractured" (not sure if I'm using the word correctly - it's not smooth, looks like the surface has a lot of small grains or dots...). And the reason is the temperature changes! I always used developer at room temperature (so about 21-25 C), very cold running water for stopping wash and fixer also at room temperature. So there was actually 2 temperature changes. Now that i think about it, it surely was devastating to gelatin, weird fact is that it didn't came off completely.
About chrome alum - a have a small stack and it's possible to get more. It's actually more difficult to get real photographic products (like Kodak Hardening Fixer and other un-typical thingies) than chemicals to make ones ;) That's why I made the developper and fixer that Marc is advising (MQ developer and Hypo fixer).
Anyway, I'll surelly peek here some time during my vacation (probably tomorrow :P), so feel free to comment and correct me.
Thanks and Cheers!
A.

Ray Rogers
08-30-2010, 04:49 PM
...making the surface of the whole plate "fractured" (not sure if I'm using the word correctly - it's not smooth, looks like the surface has a lot of small grains or dots...). And the reason is the temperature changes! I always used developer at room temperature (so about 21-25 C), very cold running water for stopping wash and fixer also at room temperature. So there was actually 2 temperature changes. Now that i think about it, it surely was devastating to gelatin, weird fact is that it didn't came off completely.

Sounds like you had some reticulation. Reticulaton isn't usually associated wth frilling or detachment; it often occurs without the others being present. One really should try to keep all solution temperatures close to each other. That should help the reticulation problem (if thats what it was) and hardening, as d. points out through the words of Baker, will help with detachment issuses.

dwross
08-30-2010, 11:08 PM
Reticulation is is caused by the uneven swelling and shrinking of gelatin pretty much constrained by its attachment to the plate. In addition to the physical appearance of wrinkles, silver grains can migrate from the valleys to the ridges, increasing the visual perception of texture or 'grain'.

Frilling starts from the same causes as reticulation, but at the edges of the plate, where water can get under the emulsion and cause waves of swelled gelatin that separate from the glass. Big temperature swings is the major cause of both reticulation and frilling, but in addition, going from a strongly alkali developer to a really strong acid stop bath can do the same thing. The major cause of serious frilling, even if all the temps and pHs are balanced, is rough handling of the plates during processing. Try not to touch the edges any more than absolutely necessary and be as gentle as possible. Also, I remember reading a caution about too-warm hands. I always wear nitrile gloves and work at 65-68F, so I've never noticed a problem with that, but it makes sense. But, all in all, as you've noticed, gelatin emulsion is pretty amazingly tough stuff. You have to really abuse it to have significant problems.