Washing Film - Best Environmentally Friendly Way to Do It?

[Photo Engineer]

In either case, you are adding a burden to the environment. The sodium sulfite in a wash aid has to go somewhere, and peroxide in your effluent is not nice either.

PE

[SchwinnParamount]

In either case, you are adding a burden to the environment. The sodium sulfite in a wash aid has to go somewhere, and peroxide in your effluent is not nice either.

PE

I don't want that stuff in the environment either but you're right... it has to go someplace.

So I drink it.


On another and probably un-related note, I've got this weird third ear growing out of the back of my head. I can hear 33% better of course, but people look at me funny.

[SMBooth]

good info, a product I don't really need. Thanks

[wogster]

Your conclusions about when to use wash aids are right on, but I have a problem with the term "wash aid" being characterized as synonymous with "hypo eliminator". They are not at all the same.

I know it sounds rather nitpicky, but I hope the terminology of wash aids and hypo eliminators becomes better understood and used since all these terms can be so confusing to beginners under even the best circumstances.

If you look back at my message you will find that Washaid was capitalized as a single word, that is usually an indication that it's being used as a product name, not a generic term. In this case you really need to take that up with Ilford. Considering that I first heard of that product 3 decades ago, it's been around a long time, they do refer to it as a hypo eliminator on their web site.

I also don't know if hypo eliminators really make a huge difference with rapid fixers that do not contain any hypo, when using the short fixing times with modern films and RC papers.

[Photo Engineer]

I also don't know if hypo eliminators really make a huge difference with rapid fixers that do not contain any hypo, when using the short fixing times with modern films and RC papers.

I know of no fixer today that has another fixing agent in it that exclusively replaces Hypo. Can you explain a bit? Thanks.

PE

[dancqu]

Hypo eliminators are completely different; they
destroy hypo within the paper rather than
helping it be removed from the paper.

"What hypo is not washed out is then turned to sodium
sulfate, which is harmless." He is writing of potassium
permanganate and the washing of film.

After a first wash the film is further washed in water
tinted with the permanganate. If the the tinted water
goes colorless further washing is needed. Dan

[CBG]

Wogster - Ilford's info on their "Washaid" branded washing aid simple adds to the confusion. They misuse the term hypo eliminator too. I think I'm fighting a losing battle.

[dancqu]

Wash aids are rather gentle in effect, merely allowing better
diffusion of water and chemicals in and out of the paper base.

Wash aids are invariably alkaline, mildly to quite. As well
as sodium sulfite alone or laced with the bisulfite there is
sodium carbonate. The latter recommended by Agfa.

I believe the mechanism involved is ion exchange.
The hydroxyl ion population being high results in
detachment of the silver bering thiosulfate
ions. Non silver laden thiosulfate, I'd
suppose ditto.

Quite a few chemicals can serve well as hypo
clearing agents. Sodium sulfite is the only
one to be quantified, publicly. Dan

[wogster]

I know of no fixer today that has another fixing agent in it that exclusively replaces Hypo. Can you explain a bit? Thanks.

PE

I thought Hypo referred to hyposulphate of soda - AKA sodium thiosulphate, the fixer I currently use is based on ammonium thiosulphate, which isn't hypo.

The real question then is, does a hypo eliminator do anything when you use an ammonium thiosulphate based fixer?

[Photo Engineer]

Hypo refers only to the Thiosulfate end of the molecule Paul.

HEs work on any thiosulfate, but since Ammonium Thiosulfate and its complexes with silver are more soluable and smaller, the effect is harder to see in some cases. But then, you have the HE to eliminate somehow!

PE