Kodak Hardening Stopbath SB-3

[Gerald Koch]

Chrome Alum Stop Bath Kodak SB-3
Agfa 216

This chrome alum stop bath provides greater hardening than can be obtained
with a white alum stop bath or fixer.

Usage

Use full strength. Agitate continuously for the first 30 to 45 seconds to avoid streaking. Allow the film to remain in the bath for 5 minutes with agitation every minute.

This stop bath rapidly loses its hardening ability and should be made up fresh
before use. A fresh bath exhibits dichroism such that it appears purple by reflected light and green by transmitted light, discard it when it turns green.

This stop bath is useful with soft emulsions like Efke.

[Captain_joe6]

Just wanted to check,what are the quantities used in this formula?

[Tom Hoskinson]

Kodak SB-3

Water 1 liter
Potassium Chrome Alum 30.0 grams

[Alessandro Serrao]

I did know that the potassium chrome alum works only in an acid environment.
The formula you've provided isn't supplying an acid environment.

Anyone can confirm this?

[FilmIs4Ever]

This is just like Kodak SB-4 but without Sodium Sulfate. For those of you using other measuring systems:

Water - 32 U.S. fl. oz. - 1 L - 40 Imp. fl. oz.
Potassium Chrome Alum - 1 oz. avdp. - 30.0g - 1 3/16 oz. avdp.

[Tom Hoskinson]

Once improper handling has damaged your Efke film emulsion, this hardener won't help.

Better IMHO, to sacrifice some film and practice your handling of it with the lights on.

[FilmIs4Ever]

Isn't that the point of hardening it before you pull it out of the fixer?

My experience with film in general (not Efke specifically) is that it's most easily damaged when it's wet, so as long as you don't manage to F it up when you're dumping out the developer and dumping this stop in, it should do the film some good.

[Tom Hoskinson]

Originally Posted by FilmIs4Ever

Isn't that the point of hardening it before you pull it out of the fixer?

My experience with film in general (not Efke specifically) is that it's most easily damaged when it's wet, so as long as you don't manage to F it up when you're dumping out the developer and dumping this stop in, it should do the film some good.

YES EFKE EMULSIONS ARE EASILY DAMAGED when DRY and when WET. THE DAMAGE HAPPENS DURING IMPROPER HANDLING (WHEN THEY ARE HANDLED WITH INSUFFICIENT CARE).

I shoot a lot of Efke 25 and Efke 100 8x10 sheet film and process it with ZERO emulsion damage and NO hardener. I do develop it in Pyrocat, which tans the emulsion.

If you feel you must use a hardened film choose one of the modern factory prehardened films made by Kodak, Ilford and Fuji.

[FilmIs4Ever]

Tom, you're being needlessly confrontational.

It is common knowledge that an emulsion can be more-easily scraped off of the film base when it is wet and swolen. Similarly, non-photographic things, things that are glued together, are especially susceptible to coming undone when they are wet.

I agree that proper, delicate handling is useful, but all films can use a hardening bath, especially if the fixer doesn't have a hardener. The Kodak 1 gal. powdered fixer that is readily available is totally unsuitable for film if it isn't hardened before-hand, so it is not only wise but essential to have some sort of hardener added to film processing formulae.

Otherwise, the *protective sleeves* can scratch the film.