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Bleach Recipe


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#1 mark_baldry

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Posted 25 August 2007 - 09:26 AM

I've been doing my own reversal B&W processing and have found by buying the kits i've ended up with a lot of developer, clearer & fixer but always run out of bleach.

rather than keep buying kits just to get the bleach can i make up my own?

the bleach i've been using is potassium permangante & sulphric acid.

i can get hold of the potassium permanganate but not the suplhric acid.

is there another chemical i can use as the acid which is easir to get hold of?

if so what would the recipe to make up the bleach?

thanks

Mark
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#2 Nick Mulder

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Posted 25 August 2007 - 09:47 AM

Try Automotive battery stores - they may have sulphuric acid ...

or ask your local college chemistry dept where they get there acid from - thats how I found my supplier ;)
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#3 mark_baldry

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Posted 25 August 2007 - 09:51 AM

Try Automotive battery stores - they may have sulphuric acid ...

or ask your local college chemistry dept where they get there acid from - thats how I found my supplier ;)


i've now found somewhere where i can get the acid but do you know what is the concentration/proportion of acid to water?

thanks

Mark

Edited by mark_baldry, 25 August 2007 - 09:51 AM.

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#4 Brian Pritchard

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Posted 25 August 2007 - 09:56 AM

I've been doing my own reversal B&W processing and have found by buying the kits i've ended up with a lot of developer, clearer & fixer but always run out of bleach.

rather than keep buying kits just to get the bleach can i make up my own?

the bleach i've been using is potassium permangante & sulphric acid.

i can get hold of the potassium permanganate but not the suplhric acid.

is there another chemical i can use as the acid which is easir to get hold of?

if so what would the recipe to make up the bleach?

thanks

Mark

Unfortunately all the bleach formulae I can find that are suitable for reversal processing, contain Sulphuric Acid; the alternative to Potassium Permanganate is Sodium Dichromate but requires Concentrated Sulphuric Acid. I would be wary of using battery acid as you don't know whether there are any additives in it that might affect the film. It has been mentioned before and only recently, that you should take great care with concentrated Sulphuric Acid. Always wear gloves and goggles and NEVER add water to the acid always add acid to water and do it SLOWLY as the water can boil. If you are splashed with the acid soak the skin with water at once.

Brian
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#5 mark_baldry

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Posted 25 August 2007 - 01:07 PM

Unfortunately all the bleach formulae I can find that are suitable for reversal processing, contain Sulphuric Acid; the alternative to Potassium Permanganate is Sodium Dichromate but requires Concentrated Sulphuric Acid. I would be wary of using battery acid as you don't know whether there are any additives in it that might affect the film. It has been mentioned before and only recently, that you should take great care with concentrated Sulphuric Acid. Always wear gloves and goggles and NEVER add water to the acid always add acid to water and do it SLOWLY as the water can boil. If you are splashed with the acid soak the skin with water at once.

Brian


thanks- but how much acid to how much water?
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#6 Brian Pritchard

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Posted 25 August 2007 - 01:21 PM

thanks- but how much acid to how much water?

The Kodak formula R-9 for Bleach bath for B/W reversal is as follows:


1 litre of water to which add 9.5 grammes of Potassium Dichromate followed by 12 mL of Concentrated Sulphuric Acid.

Brian
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#7 Nick Mulder

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Posted 25 August 2007 - 03:24 PM

thanks- but how much acid to how much water?

Lots of recipes on the net incl. the Kodak site itself

here is where I get my mixtures from: http://lavender.fort...sdeveloper.html

...problem is do you use the same amount of Sulphiric acid when you are using the permangenate soup as the dichromate version ?

www.APUG.org is another good resource ;)
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#8 James Steven Beverly

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Posted 26 August 2007 - 03:23 AM

Just FYI from Wikipedia:


* 10%, dilute sulfuric acid for laboratory use,
* 33.5%, battery acid (used in lead-acid batteries),
* 62.18%, chamber or fertilizer acid,
* 77.67%, tower or Glover acid,
* 98%, concentrated acid.

Additives

Many vendors sell chemical additives (solid compounds as well as liquid solutions) that supposedly reduce sulfate build up and improve battery condition when added to the electrolyte of a vented lead-acid battery. Such treatments are rarely, if ever, effective.

Two compounds used for such purposes are Epsom salts and EDTA. Epsom salts reduce the internal resistance in a weak or damaged battery and may allow a small amount of extended life. EDTA can be used to dissolve the sulphate deposits of heavily discharged plates. However, the dissolved material is then no longer available to participate in the normal charge/discharge cycle, so a battery temporarily revived with EDTA should not be expected to have normal life expectancy. Residual EDTA in the lead-acid cell forms organic acids which will accelerate corrosion of the lead plates and internal connectors.

Active material (the positive plate lead peroxide and negative plate spongy lead) changes physical form during discharge, resulting in plate growth, distortion of the active material, and shedding of active material. Once the active material has left the plates, it cannot be restored into position by any chemical treatment. Similarly, internal physical problems such as cracked plates, corroded connectors, or damaged separators cannot be restored chemically.

Automotive battery acid used in film processing=bad idea (Not from Wikipedia but should be) B)
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#9 mark_baldry

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Posted 26 August 2007 - 03:41 AM

thanks guys - thats great.

the bleach i've bought is 98% sulphuric acid and i've also bought potassium permanganate as this is the bleach i've been using from the kits up to know.

now i've just got to try and not blow myself up!!! :rolleyes:
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#10 Marc Roessler

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Posted 26 August 2007 - 07:57 AM

How about Sodium Bisulfate as a replacement for sufuric acid? This is listed sometimes as a possibility, is there
anyone who has tried this? Handling would be much easier than the concentrated sulfuric acid, and it is
obtained much easier as well.

Haven't tried Dichromate nor Permanganate so far, so I can't speak for any advantages or disadvantages what
concerns the results... but I'd strongly suggest against using the Dichromate... this is REALLY nasty stuff! Very
hard to obtain (and rightfully so). This will cause bad ulcers when in contact with wounds (even very small ones,
which you usually have somewhere without noticing...), and the dust is carcinogenic when breathed in (can
happen quite easily, in small amounts...). So be careful when using it!

Greetings,
Marc
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#11 Robert Houllahan

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Posted 27 August 2007 - 01:41 PM

Just went to the chemical room and looked at the Kodak cubes we get,

Part A and B are powder (part A is Sodium Tetraphospate which is basically Calgon used as a softener and chemical buffer) and Part B is the Potassium Permanganate you mix these in water and then add the Part C which is Sulphuric acid (45 to 50%) and that is how the kit comes from Kodak. Dichromate bleach does work better but it's environmentally messy, we can run almost 30K ft. in a 8 hour shift and we feel using Dichromate is irresponsible, the small amounts used for hand processing are easier to dispose of properly.


-Rob-
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#12 mark_baldry

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Posted 28 August 2007 - 07:24 AM

add the Part C which is Sulphuric acid (45 to 50%)


Rob - are you saying that 45-50% of the bleach solution is pure sulphuric acid? i.e. 500ml of 1000ml quantity of bleach. the solution i have bought is 98% - how much do i need to dilute it down to?

thanks

Edited by mark_baldry, 28 August 2007 - 07:26 AM.

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#13 Robert Houllahan

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Posted 28 August 2007 - 10:10 AM

Rob - are you saying that 45-50% of the bleach solution is pure sulphuric acid? i.e. 500ml of 1000ml quantity of bleach. the solution i have bought is 98% - how much do i need to dilute it down to?

thanks



No the final bleach solution is more diluted (I will post ratios when I get to Cinelab today) the sulphuric acid is delivered to us at 45-50% concentration from Kodak. I think this just makes it safer and easier for lab tech's

More in a bit

-Rob-
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#14 Robert Houllahan

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Posted 28 August 2007 - 01:16 PM

All right here we go......


As used in a lab.....

We mix 15gallons (56.8L) of water with 1817g of Calgon S and 908.4g of Potassium Permanganate and then add 8 litres (8054 ml) of 45-50% solution of sulphuric acid and then top off with water to 20gallons (75.7L) this is Replenisher.

I would mix your 98% acid down to 45-50% at 8L of total sulphuric acid solution first....

Then make the Calgon/Permanganate solution and mix the acid in next, this is a replication of the Kodak kit chemistry.....


To make tank solution take that 20gallons you made and dilute 1 part Replenisher Bleach (as above) solution to 3 parts water......


You want to keep the Bleach in a sealed container and minimize the amount of air and also watch out for the material you mix and package in do not use polypropylene or stainless steel PVC or Titanium are preferred but this stuff eats everything practically very corrosive....

Also keep in mind that the bleach has to be vigorously agitated when used....

-Rob-
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#15 mark_baldry

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Posted 29 August 2007 - 02:39 AM

All right here we go......
As used in a lab.....

We mix 15gallons (56.8L) of water with 1817g of Calgon S and 908.4g of Potassium Permanganate and then add 8 litres (8054 ml) of 45-50% solution of sulphuric acid and then top off with water to 20gallons (75.7L) this is Replenisher.

I would mix your 98% acid down to 45-50% at 8L of total sulphuric acid solution first....

Then make the Calgon/Permanganate solution and mix the acid in next, this is a replication of the Kodak kit chemistry.....
To make tank solution take that 20gallons you made and dilute 1 part Replenisher Bleach (as above) solution to 3 parts water......
You want to keep the Bleach in a sealed container and minimize the amount of air and also watch out for the material you mix and package in do not use polypropylene or stainless steel PVC or Titanium are preferred but this stuff eats everything practically very corrosive....

Also keep in mind that the bleach has to be vigorously agitated when used....

-Rob-



thanks Rob thats just what i was after.

Mark
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