Copper Sulphate Bleach

teejay · Jun 6, 2017

Hi - so I'm going to try and make my own copper sulphate bleach for use in 2nd pass with - I was going to use this formula:

Copper (Cupric) Sulfate..................................50 g
Concentrated Sulfuric Acid (EXTREME CARE!)..............6.5 ml
Sodium Chloride (Common Salt)........................... 50 g
Water to make..........................................1000 ml

...but it looks like obtaining sulphuric acid here in the uk is quite hard unless you can prove you're buying on behalf of a company or educational establishment - which is probably fair enough. So can the sulphuric acid be swapped out for something else more readily available ?

pdeeh · Jun 6, 2017

teejay said:
t it looks like obtaining sulphuric acid here in the uk is quite hard unless you can prove you're buying on behalf of a company or educational establishment - which is probably fair enough. So can the sulphuric acid be swapped out for something else more readily available ?

It's not at all hard to buy concentrated sulfuric acid here. I've got a litre of it. Try ebay or apcpure.co.uk

However it is horrible stuff, and all you really need is to buy some battery electrolyte from a Halfords or similar (or ebay again).

That will be sulfuric acid diluted to 25-35% (the % dilution should be marked on the container), and you then adjust the volume of acid (and water of course) in your bleach to compensate.

You still need to be careful of course and observe appropriate precautions.

PS OK a quick look at the first electrolyte I found on eBay was 38%.
So for your formula you would substitute ~17ml of electrolyte for the conc. Sulfuric acid.
Remember, whatever you use, add acid to water not water to acid.

RauschenOderKorn · Jun 6, 2017

teejay said:
Sodium Chloride (Common Salt)

"Common Salt" will do, but make sure that you find some without additives like to prevent sticking or to make it "healthier". The purest "Common Salt" you can get in Germany is gritty seasalt which only has the "natural" impurities and nothing else added.

pdeeh said:
Remember, whatever you use, add acid to water not water to acid.

+1 I´d even say "Add acid to a generous amount of water"

paul ron · Jun 6, 2017

auto parts stores sell battery acid.... (usa)

37% sulfuric acid

Gerald C Koch · Jun 6, 2017

Stick with the permanganate bleach that Ilford recommends. Copper sulfate is one of those bleaches that causes softening of the emulsion.

pdeeh · Jun 6, 2017

Gerald C Koch said:
Stick with the permanganate bleach that Ilford recommends. Copper sulfate is one of those bleaches that causes softening of the emulsion.

He's not doing reversal, this is for 2nd pass lith, as per his op

desertrat · Jun 6, 2017

Sodium bisulfate (sodium hydrogen sulfate) can be substituted for sulfuric acid in some processes and is easy to get in the USA as swimming pool ph reducer.

However, I don't know if it would work in this photographic formula. It would be an interesting experiment for someone who has both sulfuric acid and sodium bisulfate on hand.

teejay · Jun 6, 2017

Thanks for replies - I didn't think of using the lower concentrate stuff and adjusting - doh - I'd ordered 96% pure from apc and they sent an assessment form saying they wouldn't process the order until it was assessed - cool , I get hold of some of the battery stuff instead - ta

john_s · Jun 6, 2017

teejay said:
Thanks for replies - I didn't think of using the lower concentrate stuff and adjusting - doh - I'd ordered 96% pure from apc and they sent an assessment form saying they wouldn't process the order until it was assessed - cool , I get hold of some of the battery stuff instead - ta

Good move. Although the battery acid is very dangerous, concentrated sulphuric acid is horrendous if you have an accident with it.

pdeeh · Jun 6, 2017

teejay said:
I'd ordered 96% pure from apc and they sent an assessment form saying they wouldn't process the order until it was assessed

Oh that's interesting.
Mine came from APC no questions asked, but probably a couple of years ago.
It would not surprise me if this was a response to the increasing number of acid attacks being reported. Horrifying, so understandable.
You used to be able to get very strong Sulfuric drain cleaners in B&Q, Dyas, etc.
Funnily enough I was in a Robert Dyas today looking for something else and remembered your comment, but couldn't see any of them. Again, perhaps for the same reason.
Mind you, they did have bottles of Hydrochloric acid ("Spirits of Salt") at ~35%, and that wouldn't do you much good if you got it full in the face either, but conc. Sulfuric is in a league of its own when it comes to immediate and devastating damage to human flesh.

Gerald C Koch · Jun 6, 2017

desertrat said:
Sodium bisulfate (sodium hydrogen sulfate) can be substituted for sulfuric acid in some processes and is easy to get in the USA as swimming pool ph reducer.

However, I don't know if it would work in this photographic formula. It would be an interesting experiment for someone who has both sulfuric acid and sodium bisulfate on hand.

Sodium bisulfate works just fie and can be easier to obtain.

RauschenOderKorn · Jun 7, 2017

Question for the chemists: Could the sulphuric acid be replaced by the hydrochlorid acid already mentioned?

Rudeofus · Jun 7, 2017

Not a chemist, but I would see no reason why Hydrochloric Acid wouldn't work. I would have assumed, though, that Hydrochloric Acid is less desirable for its smell.

@teejay: many old recipes use concentrated acids, because shipment/storage of them was considered easier back then. In the meantime, several of these products in their concentrated form have been used for nefarious purposes, and their sale is severely restricted now. A site hosting this kind of recipe should probably reformulate it to use the more available dilute versions of these acids.

teejay · Jun 7, 2017

Just for completeness, this is the reply I received back:

"Hi

Thank you for your recent order.

Unfortunately we can now only supply to Limited companies, Partnerships, Sole Traders, Trading Businesses.

We would also need to know the application for which you intend to use this product.

If you do not meet the criteria we will be unable to proceed with your order and are happy to refund the item

If you feel you meet the criteria listed above, please complete the attached form and return it to us for approval.

I apologise for any inconvenience this causes."

paul ron · Jun 7, 2017

for the small amount you need, just go out to your car n suck up a few mls from each cell? then refill your battery with distilled water.

Gerald C Koch · Jun 7, 2017

RauschenOderKorn said:
Question for the chemists: Could the sulphuric acid be replaced by the hydrochlorid acid already mentioned?

The bleach needs to be acidic for it to work correctly. You can use hydrochloric acid.

Gerald C Koch · Jun 7, 2017

paul ron said:
for the small amount you need, just go out to your car n suck up a few mls from each cell? then refill your battery with distilled water.

A very bad suggestion as you may damage a battery to make a print. Doesn't make sense.

RauschenOderKorn · Jun 7, 2017

paul ron said:
for the small amount you need, just go out to your car n suck up a few mls from each cell? then refill your battery with distilled water.

The used battery acid will contain a significant amount of lead. I doubt this is good for your print.

Gerald C Koch · Jun 7, 2017

Modern lead-acid batteries are sealed and use a jellied electrolyte.

Copper Sulphate Bleach

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