Sulfuric acid concentration/sources?

[vinny]

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]

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,

Doug

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

[vinny]

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.

[Salty]

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]

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
http://www.galerie-photo.com/inversion-film-noir-blanc.html
B&W slides are great !!
And will survive you ;)