Wanting to try reversal processing but also not die

[Raghu Kuvempunagar]

For film reversal, I doubt 2-3% peroxide would do well. In the only experiment I did, it took too long to do bleaching and resulted in many pinholes. Didn't try the more dangerous 9-10% peroxide concoction that others have used to get good results like this person:

https://www.photrio.com/forum/threa...iocyanate-containing-first-developers.169169/

 

[Agulliver]

3% hydrogen peroxide isn't much stronger than that available in mouth wash. While I would certainly advise against drinking it, it's considered sufficiently safe to swill one's mouth with. 9-10% is strong enough to be corrosive to the skin and would likely be more useful as reversal bleach.

 

[138S]

Yep, that would probably be better. That was just an idea I had for "develop by inspection" adjustment, and would require an experienced eye, like any DBI process.

A good way to calibrate R processing for a certain film is calibrating it with different settings, better with absolute H units, then with Photoshop we overlap the calibrated curves with those in Provia datasheet (or TX for cinematographers) , this allows to selec the settings for a suitable contrast and what speed we should use, relative to provia. This is the fastest way, when curve is correct it will work optimally in the first try, beyond fine aesthetic adjustments be may later make. I also delivers first class information about how to control processing to meet a cetain goal with precision.

If we are to scan then we can adjust many things in Ps, but for projection contrast has a really narrow margin compared to the one (for example) Provia has. In my experience H-D calibrations are way more useful for reversal than for negatives. It's about mastering what Beyond The Zone System book explains...

 

[Donald Qualls]

Eeek! That sounded like a bunch of digital stuff! For shame!

I'd much rather shoot a bracketed test roll of my chosen film (Foma R100, say), cut it in bracket groups after first dev (which I'll be able to see a negative image, so can cut accurately) and then bracket the reducing bath. Might have to do a couple rolls to get the first dev fully dialed in, though, since I keep hearing that standard negative development isn't right (speed issues, contrast issues, etc.) -- never mind that the Tri-X I've done this with got the same first dev I'd have given for negatives.

 

[138S]

Eeek! That sounded like a bunch of digital stuff! For shame!

Not at all ! fortunately.

Ps is used to overlap graphs, not images of scenes !

This is a series of tests I made recently for a new processsing, compared with matching scales to Provia and TX, no one worked, but in the graph it is quantitatively displayed why: issues with DMin, DMax, and contrast are seen, so it shows me the path to obtain an optimal yield for the next time.



The curves show that I only have to increase contrast to match TX (in cinematography), but I have additional work to match Provia dynamyc range in the projection, which is my goal.

Also negative development curve is shown for a processing, which allows to see if development has to be more energetic.

An analytic approach can be useful when many factors are in play, for example when adding Se toning to increase DMax.

 

[Lachlan Young]

Eeek! That sounded like a bunch of digital stuff! For shame!

I'd much rather shoot a bracketed test roll of my chosen film (Foma R100, say), cut it in bracket groups after first dev (which I'll be able to see a negative image, so can cut accurately) and then bracket the reducing bath. Might have to do a couple rolls to get the first dev fully dialed in, though, since I keep hearing that standard negative development isn't right (speed issues, contrast issues, etc.) -- never mind that the Tri-X I've done this with got the same first dev I'd have given for negatives.

Given that Foma, Kodak and Ilford all recommend essentially the same acidified permanganate bleach bath, but with widely varying times of immersion (1 min Kodak to 5 mins from Ilford), there is clearly scope for some refinement.

Regarding first developer, I'll leave these two links here, as they're fairly precisely geared towards what you are asking about.

1

2

Bracketed tests should be fine - it'll be pretty obvious if you get a good Dmax and Dmin. Bear in mind that films intended for BW reversal do have extra silver in them to improve the Dmax.

 

[Raghu Kuvempunagar]

Might have to do a couple rolls to get the first dev fully dialed in, though, since I keep hearing that standard negative development isn't right (speed issues, contrast issues, etc.)

This could be of some help:
https://www.flickr.com/groups/1924424@N22/discuss/72157629499928508/

 

[Anon Ymous]

Given that Foma, Kodak and Ilford all recommend essentially the same acidified permanganate bleach bath, but with widely varying times of immersion (1 min Kodak to 5 mins from Ilford), there is clearly scope for some refinement.

I always used permanganate bleach and it always worked fine. The bleach I use is made with deionised water and

1g/l Potassium permanganate
50g/l Sodium bisulfate

It's good to dissolve permanganate in half the amount of water needed and let it rest there, while giving it the occasional stir. It dissolves rather slowly and it's too dark to figure out if it has completely dissolved, so filtering the permanganate solution is a very good idea.

Before committing any films to processing that I haven't tried before, I do the first three steps of the process in full light, in q graduate. I develop a piece of film in FD, then rinse, bleach and clear. The film seems to be fully bleached in a minute or so, at 20°C. Regardless of this, I bleach for 5' and I haven't had a single case of emulsion sliding off the base, or become too soft to touch. That said, I don't remove the film from the reel and expose to light on typical Jobo and Paterson reels. Another poster said something about light fogging being uneven, but if you keep the film immersed in a bowl of water, then it will give perfectly even fogging, no marks whatsoever. I don't use any fancy high wattage lights, just a 70W tungsten bulb at a distance of 20-30cm for a couple of minutes from each side of the reel. I also spin the reel in the water while exposing to light.

 

[mohmad khatab]

Wish PE or Jerry Koch were still here to chime in, but I've stayed away from mixing hydrogen peroxide and acetic acid due to the possibility of forming paracetic acid. Several of us have used citric acid and hydrogen peroxide for paper reversal, and I think it's been used for film as well. There's a long thread about it somewhere here at photrio. I've been meaning to try the copper bleach, but with sodium bisulfate.... got as far as purchasing the copper sulfate...

Copper sulfate is used with sodium chloride and not with sodium bisulfate.
Sulfate + sulfate =?
This is what I know.

 

[Donald Qualls]

The bisulfate is used as a reserve of sulfate++ ions, sometimes as a complete substitute for the sulfuric acid, and sometimes just so you don't need to use as much acid. In sulfate bleaches (including permanganate and dichromate versions), it's been my understanding that the developed silver is converted to soluble silver sulfate, with the permanganate or dichromate (powerful oxidizers) acting as catalyst and the sulfuric acid supplying sulfate. If you start with copper sulfate, you have sulfate already in the solution, so the bleach still works without adding sulfate -- but it'll have much more capacity if there's a sulfate reserve in the solution.

 

[138S]

permanganate bleach

Shelf life is, once mixed, of no more than two weeks. If a doubt, better making the bleaching lights open, so we can see if it works, also we see the bleach strength from the clearing time, so we can bleach the right time. I learned that after ruining some fllm...

 

[mohmad khatab]

The bisulfate is used as a reserve of sulfate++ ions, sometimes as a complete substitute for the sulfuric acid, and sometimes just so you don't need to use as much acid. In sulfate bleaches (including permanganate and dichromate versions), it's been my understanding that the developed silver is converted to soluble silver sulfate, with the permanganate or dichromate (powerful oxidizers) acting as catalyst and the sulfuric acid supplying sulfate. If you start with copper sulfate, you have sulfate already in the solution, so the bleach still works without adding sulfate -- but it'll have much more capacity if there's a sulfate reserve in the solution.

Great ,,
This is new information for me and a different vision that did not cross my mind.
God bless you, thank you for the information,
But an intuitive inquiry comes to my mind:
(Regardless of the sputum problem) Does this mean that we can use copper sulfate and only without sodium chloride and without sulfuric acid? (At least in theory)?

 

[mohmad khatab]

Shelf life is, once mixed, of no more than two weeks. If a doubt, better making the bleaching lights open, so we can see if it works, also we see the bleach strength from the clearing time, so we can bleach the right time. I learned that after ruining some fllm...

What do you suggest to make this bleach solution can live long (in your view)?

 

[NedL]

Copper sulfate is used with sodium chloride and not with sodium bisulfate

Right, sorry I was not very clear. I meant Copper sulfate, sodium chloride, and a little sodium bisulfate instead of sulfuric acid.

 

[mohmad khatab]

Right, sorry I was not very clear. I meant Copper sulfate, sodium chloride, and a little sodium bisulfate instead of sulfuric acid.

Yes, yes, it is now clear.
God bless you . Thanks for the clarification .
Actually, I don’t know, why do most people move away and flee from sulfuric acid, even though I find it to be a very pleasant, kind and respectful element.
I find no justification for escaping from sulfuric acid.
- I find myself very sympathetic to sulfuric acid,
I am also very sympathetic to the use of copper bleach in the process (C41) but with another very different formula.
The attached image was developed using a copper bleach (the formula for process C41) taking into account that this is an expired film, and the potassium iodoid ratio was uncontrolled, (1.4mg) by mistake was set (1.4)
I am a defender of copper bleach and a defender of sulfuric acid....

 

[Donald Qualls]

Does this mean that we can use copper sulfate and only without sodium chloride and without sulfuric acid? (At least in theory)?

The question I'd have is whether there's enough sulfate present if you don't add any. I don't know the purpose of the sodium chloride in a bleach you'd use for B&W reversal; you surely don't want to rehalogenate the developed silver as you'd do in C-41 or E-6 to allow fixing it away. I've have to experiment with copper sulfate without added acid or sodium bisulfate to be sure, but intuitively I would expect some bleaching action, but very low capacity -- you'd need a lot of copper sulfate to do the job.

 

[mohmad khatab]

The question I'd have is whether there's enough sulfate present if you don't add any. I don't know the purpose of the sodium chloride in a bleach you'd use for B&W reversal; you surely don't want to rehalogenate the developed silver as you'd do in C-41 or E-6 to allow fixing it away. I've have to experiment with copper sulfate without added acid or sodium bisulfate to be sure, but intuitively I would expect some bleaching action, but very low capacity -- you'd need a lot of copper sulfate to do the job.

Copper bleach formula for C41 (Agfa).
700 ml deionized water 52 ° C
Potassium Alum ....................20 g
Sodium sulfate..................... 25 g
copper sulfate Anhydrous .... 40 g
Potassium bromide.............. 20 g
Sulfuric acid (37%)............... 5 ml
.Water up to 1 liter

 

[Raghu Kuvempunagar]

I don't know the purpose of the sodium chloride in a bleach you'd use for B&W reversal;

When sodium chloride is used with copper sulphate, it makes a rehalogenating bleach. In B&W reversal processing, this bleach converts the negative silver image into silver chloride. If the bleach step is followed by a rinse in dilute ammonia solution, all the silver chloride is removed while the silver bromide is left intact for subsequent steps of reversal processing.

 

[Donald Qualls]

When sodium chloride is used with copper sulphate, the bleach acts as a rehalogenating bleach. In B&W reversal processing, this bleach converts the negative silver image into silver chloride. If the bleach step is followed by a rinse in dilute ammonia solution, all the silver chloride is removed while the silver bromide is left intact for subsequent steps of reversal processing.

Wow. That's a good example of going around your ear to get to your elbow. The copper bleach just above your post, for an old C-41 process, is what I'd expect for a rehalogenating bleach, though it's unclear why you'd use copper sulfate in that context rather than potassium ferricyanide. You don't need the acidity (in fact, need to avoid it), get rehalogenated silver and are ready for the fixer. Maybe it's a matter of working faster; I don't know.

 

[mohmad khatab]

Wow. That's a good example of going around your ear to get to your elbow. The copper bleach just above your post, for an old C-41 process, is what I'd expect for a rehalogenating bleach, though it's unclear why you'd use copper sulfate in that context rather than potassium ferricyanide. You don't need the acidity (in fact, need to avoid it), get rehalogenated silver and are ready for the fixer. Maybe it's a matter of working faster; I don't know.

Yes, brother ,,
You need some acidity in order to get more speed to perform the operation in a reasonable time.
- What is the problem ?
In general, I am not the creator of this formula, I came from Germany a long time ago and it is the formula that produced the best and most accurate results (in relation to the copper bleach formulas published in the world)
I do not use ferricyanide because it is so expensive in my country and it is almost considered not allowed to sell it officially (I don't know why), let alone being more harmful to the environment.
Aqueous copper sulfate is one kilo = 2 $
Anhydrous copper sulfate one kilo = $ 8
One potassium ferricyanide kilo = 55- $ 95 (depending on the brand and country of origin) in addition to that the seller asks you to prove to him that you are an honorable man and you will not use that element in evil deeds.
If you were me, what would you do?
Trust me, prepare this bleach and test it, and believe me, you will love it very much.
Also, economically, it is very cheap and remains alive for very long periods.
- Everything, when you feel that it has become somewhat dark in color from the frequent use, you can filter it with a light cotton ball with the funnel, it will come back to life again.
Greetings to you.

 

[Raghu Kuvempunagar]

Wow. That's a good example of going around your ear to get to your elbow.

How would you otherwise use copper sulphate to remove the silver image in b&w reversal processing?

The idea of using sodium chloride with copper sulphate for b&w reversal processing came from Athiril and is detailed in a thread by him with a lots of insightful discussion about the method. You might want to look at it before making comments like the above. Here's the link: https://www.photrio.com/forum/threads/copper-sulphate-b-w-reversal-bleach.137943/

The rehalogenating bleach formula you referred to has bromide in it. It may work for C41 but certainly not for reversal processing of b&w films.

 

[Raghu Kuvempunagar]

better making the bleaching lights open, so we can see if it works

This is a good suggestion for most films I've tried with the exception of Adox CMS 20 ii. It's best to bleach this film in the dark in my experience.

 

[138S]

What do you suggest to make this bleach solution can live long (in your view)?

I don't know it, this has been a drawback of the permanganate bleach since many decades ago, so if no chemist found a solution...

Possibly a cold storage may help to conserve it, as in general chemical reactions are cinetics slowed with lower a temperature.

 

[138S]

with the exception of Adox CMS 20 ii. It's best to bleach this film in the dark in my experience.

It is a very special fim, what surpirsed me is this statement in the datasheet:

"After the development you MUST use an acidic stop bath before fixing. Do NOT use plain water."

They do not say why, but perhaps the reason has a link with what you say.

 

[mohmad khatab]

[QUOTE = "Donald Qualls, post: 2266556, member: 4594"] Eeek! Seems to be a bunch of digital things! what a shame!

I prefer to shoot a test shot of my chosen movie (Foma R100, for example), and cut it in brackets after the first development (which I will be able to see a negative image, so that I can precisely cut it) and then the stylized bathroom bracket. You might have to do some laps to get the first fully contacted developer, although I keep hearing that standard negative development isn't right (speed problems, contrast problems, etc.) - it doesn't matter that Tri-X I did it with getting On the same first development that I gave to the negatives. [/ QUOTE]
I mostly agree with you.