View Full Version : Sulfuric acid concentration/sources?

24-Jan-2008, 21:26
I ordered the necessary chemicals according to Ilford's Reversal processing pdf.
They call for Sulfuric Acid but the concentration isn't stated. They do say that weak concentrations ie 10% can be used. Page 2 of the pdf on the right. I emailed ilford earlier in the week and i'm waiting to hear back.
I didn't order it from Formulary cuz i didn't see that they had it. They sell 45% concentration. Another source i found sells 96% concentration.
What concentration do i need?

I read that weaker concentrations aka "battery acid" are available but i can't find anything here in L.A. I tried several auto parts stores, they led me to water for batteries.

Doug Herta
24-Jan-2008, 21:37
Do you have a Shucks or Murrays Auto Parts store? The 32 oz box of battery acid is part #6081079. It is 36% i believe. For the Ilford recipe it would be 30 ml to 470 ml water to get 500 ml of a similar concentration.

I do:

1 g Pot Permanganate to 250ml water
15ml battery acid to 235ml water

to make 500 ml bleach. Works for me.

Hope this helps,


Holy cow I have been a member of this board for ten years

24-Jan-2008, 22:03
No shucks or murray's. A google search goes to partsamerica.com which kragen also goes to. I can do online ordering for 32oz. exide battery acid, pickup at a kragen close by. I'll try that this weekend.

25-Jan-2008, 05:54
I got my battery acid at Kragens, they keep it behind the counter. Eventually I started using sodium bisulfate instead because the Formulary uses it in their Reversal kits. Sodium bisulfate can be found in the pool supply section at any Home Depot

Emmanuel BIGLER
25-Jan-2008, 06:56
What concentration do i need?
Concentrated sulphuric acid is a very dangerous chemical. Starting from a diluted solution as used in batteries is much better. Even a 45% solution is much less dangerous than concentrated acid.
The rule is that you should never pour water inside the acid, always add the acid to the water i.e. a small amount of the dangerous stuff into a much bigger quantity of water.
The actual value of sulphuric acid concentration does not seem to be very critical for the reversal process, I have read from various sources figures that vary from a few % to 10%.

Here I can put a pointer to an article in French, the article contains many links to various web sites in English
B&W slides are great !!
And will survive you ;)