(I'm not a native English speaker, so apologize for any gramma/spelling mistakes)
I'm looking for some safe way to make reversal B&W films.
Here are some bleach I found:
1. potassium dichromate + H2SO4 (Dangerous, I don't want to die or get cancer)
2. H2O2 +Citric Acid + EDTA + Sodium Bicarbonate https://www.photrio.com/forum/resources/b-w-reversal-bleach-—-hydrogen-peroxide-edta-citric-acid.448/
3. KMnO₄ + H2SO4
4. Copper bleach（but need ammonia water for second bath, and it's kind of dangerous)
5.cerous sulfate+h2so4，it's kind of expensive
I don't want to die, so I won't choose 1 and 4.
I don't have a lot of money, so I don't want to use 5.
2 and 3 sounds good, but, there are some problems:
1. both of them needs to mix when you use, the mixture can't last for long
2. the oxidation is too strong, some might damage your film
When I google Standard electrode potential, here is what I found:
Fe³⁺＋e⁻ ⇌ Fe²⁺ +0.77
Ag⁺＋e⁻ ⇌ Ag(s) +0.7996
This means, that although the electric potential of iron is slightly lower, trivalent iron can also oxidize silver as long as the concentration is high enough.
So, I do my test:
50g Fe2(SO4)3
15ml 37.4% H2SO4/99%Acetic acid
add water to 300ml
10min of bleaching
It did work.
Here are two test film:
But:
1.Some iron staining after bleaching
2. After second developing, my Film reel was covered by some grey matter(silver?)
3.There are a lot of particles on my film, it's hard to be wash out, I use my figer to wipe it out.
4.I need to drop the film to cleaning bath without cleaning under water, or Fe(OH)3 will stick on the film, and can't not removed
-----
So, Iron bleaching is a possible way, and it needs improvement.
Why do I know it can be improved?
Well, someone is selling a "NEW SAFE BLEACH", and it looks like this:
the color is exactly like my formula's!
But, it claimed that it's Acetic acid based, and it's PH value is 【0.2】! That doesn't make sense!
My bleach needs about 10min to sort of clean out the silver on the film, but the "SAFE BLEACH" I bought is only takes 5min( and it's already clean enought for me at 2 and half min!)
There is no silver particles stick on the film, and the film after bleach looks different
Mine bleach is white, with some grey.
while the one I bought is white, with some yellow(or green?)
I use the same film, and the same developing agent, cleaning bath(all from the "SAFE BLEACH" suit)
But, the one I bought seems much better.
I tested it on some films, the grelyish two in middle is the one I bought, the 1st and 4th one is mine.
Some info about this suit:
Bleaching: ph:0.2, 50ml solution is 58g
cleaning bath: ph:2.5
Anyone have any idea how to improve this bleaching method?
I'm looking for some safe way to make reversal B&W films.
Here are some bleach I found:
1. potassium dichromate + H2SO4 (Dangerous, I don't want to die or get cancer)
2. H2O2 +Citric Acid + EDTA + Sodium Bicarbonate https://www.photrio.com/forum/resources/b-w-reversal-bleach-—-hydrogen-peroxide-edta-citric-acid.448/
3. KMnO₄ + H2SO4
4. Copper bleach（but need ammonia water for second bath, and it's kind of dangerous)
5.cerous sulfate+h2so4，it's kind of expensive
I don't want to die, so I won't choose 1 and 4.
I don't have a lot of money, so I don't want to use 5.
2 and 3 sounds good, but, there are some problems:
1. both of them needs to mix when you use, the mixture can't last for long
2. the oxidation is too strong, some might damage your film
When I google Standard electrode potential, here is what I found:
Fe³⁺＋e⁻ ⇌ Fe²⁺ +0.77
Ag⁺＋e⁻ ⇌ Ag(s) +0.7996
This means, that although the electric potential of iron is slightly lower, trivalent iron can also oxidize silver as long as the concentration is high enough.
So, I do my test:
50g Fe2(SO4)3
15ml 37.4% H2SO4/99%Acetic acid
add water to 300ml
10min of bleaching
It did work.
Here are two test film:
But:
1.Some iron staining after bleaching
2. After second developing, my Film reel was covered by some grey matter(silver?)
3.There are a lot of particles on my film, it's hard to be wash out, I use my figer to wipe it out.
4.I need to drop the film to cleaning bath without cleaning under water, or Fe(OH)3 will stick on the film, and can't not removed
-----
So, Iron bleaching is a possible way, and it needs improvement.
Why do I know it can be improved?
Well, someone is selling a "NEW SAFE BLEACH", and it looks like this:
the color is exactly like my formula's!
But, it claimed that it's Acetic acid based, and it's PH value is 【0.2】! That doesn't make sense!
My bleach needs about 10min to sort of clean out the silver on the film, but the "SAFE BLEACH" I bought is only takes 5min( and it's already clean enought for me at 2 and half min!)
There is no silver particles stick on the film, and the film after bleach looks different
Mine bleach is white, with some grey.
while the one I bought is white, with some yellow(or green?)
I use the same film, and the same developing agent, cleaning bath(all from the "SAFE BLEACH" suit)
But, the one I bought seems much better.
I tested it on some films, the grelyish two in middle is the one I bought, the 1st and 4th one is mine.
Some info about this suit:
Bleaching: ph:0.2, 50ml solution is 58g
cleaning bath: ph:2.5
Anyone have any idea how to improve this bleaching method?
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