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Bleach for B&W reversal


nils_eidvall

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<p>Hello, I plan to develop some kodak 16mm plus-x reversalfilm in my Lomo-tank but I find it impossible to find me some bleach necessary for the processing.<br>

Developers, fixers and wetting agents are easy to find but the bleach is really hard, were should I look?</p>

<p>What I plan to use is<br>

D-76 for first developer<br>

? for bleach<br>

Re-exposure<br>

D-76 for the second developer<br>

Kodak rapid fixer as (you know) fixer</p>

<p>Should I also use the hypo clearing agent and the kodak photo flo as usual?<br>

I have also heard that the D-19 is suitable for reversal B&W but I dont know why.<br>

Is there something else I have missed and can any one help me please?</p>

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<p>Impossible? Bleach for B&W has been around since the 1900s. <br>

The Kodak publictaion for labs processing B/W reversal can be found here.<br /><a title="External link" href="http://www.kodak.com/US/plugins/acrobat/en/motion/support/processing/H-661.pdf" rel="nofollow external">http://www.kodak.com...ssing/H-661.pdf</a><br />Try as I may I could not find anywhere on their website that gives the current formulae for B/W Reversal Processing. The current process uses permanganate bleach. The original formula:<br /><br />Kodak R21a Bleach Bath<br /><br />Water 750ml<br />Potassium Dichromate 50g<br />Sulphuric acid (conc) 50ml<br />Water to 1 litre</p>

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If you struggle to get the acid H2SO4 then look for 'battery

acid'. I don't know about 16mm but for 35mm it calls for 2%

strength in solution. If battery acid was, say, 25% strength

and you needed 400ml of solution, then 2% of that should be

pure H2SO4. That's 8ml. With the battery acid, you need ?

*0.25 = 8. In this instance it's 32ml battery acid and 368ml

water

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<p>for bleach, I Mix up the bleach in 2 parts, 500ml each. keep em separate until time to use. I add them together at same time. it is not real stable but can be used up to 4 times once mixed if used within a few hours of being mixed together. Part A is 500 ml water with 3g of Potassium dichromate and part 2 is the acid, 500ml water with 12.5 grams Sodium Bisulphate. I got the Sodium Bisulphate at a pool supply company as pool acid. slow agitation for 10 minutes. Your leader (when complete) should be clear. if not, you have not bleached enough.</p>

<p>just an FYI, I use a chemical reversal step and its much easier than re-exposure with a light source. Peter Cater should chime in. he is the one who gave me his recipe for the process and its great. </p>

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