B&W Reversal with Hydrogen Peroxide

[Lachlan Young]

But, I wrote to Wolfgang Moersch about getting ahold of HEDP/editronic acid and we'll see if I hear back. Unless @Lachlan Young knows how to buy direct from Suvatlar that seems like the only reasonable route to get it.

I keep forgetting that Moersch's German pages often have more detail than the English ones - Moersch gives a direct email for Suvatlar - fotosuvatlar@live.de

Moersch also states that you should order direct from Suvatlar unless you want to combine with an order of Moersch materials to save shipping costs.

 

[relistan]

This bleach from the Konica patent also looks pretty easy to try out:

• Hydrogen peroxide (35% aqueous solution) 60ml
  
• Sodium chloride 0.3g
  
• Glacial acetic acid 30ml
  
• Zinc sulfate 3.0g
  
• Water to 1L
  
• The solution was adjusted to pH 4.0 with a sodium hydroxide solution.

 

[relistan]

I keep forgetting that Moersch's German pages often have more detail than the English ones - Moersch gives a direct email for Suvatlar - fotosuvatlar@live.de

Moersch also states that you should order direct from Suvatlar unless you want to combine with an order of Moersch materials to save shipping costs.

Thanks!!

 

[Lachlan Young]

Thanks!!

Here's a link to Suvatlar's 2021 pricelist too. I need to see if he can supply some nitrilotriacetic acid.

Item Nr.40 is what you want to get acidified permanganate bleaches to last.

 

[YoIaMoNwater]

Here's a link to Suvatlar's 2021 pricelist too. I need to see if he can supply some nitrilotriacetic acid.

Item Nr.40 is what you want to get acidified permanganate bleaches to last.

Wait what is that chemical and how does it increases the shelf life of permanganate bleach?

 

[Lachlan Young]

Wait what is that chemical and how does it increases the shelf life of permanganate bleach?

Calgon-Photo is Sodium Hexametaphosphate - regular Calgon used to be the same, but then changed to a different formulation - and it acts as a manganese sequestrant in acidified permanganate bleaches, making them last for much longer. It's one of these ingredients that often gets dismissed as being 'for water quality' when seen in an ingredients list, but there's an Agfa patent (EP1006408A1 - only in German as far as I can tell, apart from Google's automatically translated version) which shows that 20g/l is about optimal for preventing the manganese deposits appearing & extending the bleach life into weeks.

 

[relistan]

Here's a link to Suvatlar's 2021 pricelist too. I need to see if he can supply some nitrilotriacetic acid.

Item Nr.40 is what you want to get acidified permanganate bleaches to last.

Thanks Lachlan. I wrote to Suvatlar and will see what they say

 

[relistan]

Suvatlar has HEDP/Etidronic acid/Fotoplex 2 and are going to send me some

 

[kentanghk]

Some update on my EDTA experiment:

I added various amount of EDTA to the phthalate-peroxide bleach. Interestingly this seemed to increase the rate of bleaching and reduce staining. Blistering is also reduced.

Here is the formula I used:
Hydrogen peroxide (35%) 95.2ml/L
Potassium hydrogen phthalate 7.15g/L

I split the bleach in four and added EDTA disodium dihydrate to reach following concentrations.
1. 0g/L
2. 0.55g/L
3. 1.1g/L
4. 2.2g/L

pH was adjusted with NaOH to pH5

I developed a piece of Lucky SHD 100 in HC110 with sodium carbonate added. Bleached the developed film for 10 minutes at 38C. Fixed in flexicolor fixer and then washed and dried.

This is how they looked after bleaching for 5 minutes.

And this is how they looked after bleaching for 10 minutes.

This is how they looked after fixing and drying.

I will take the film home and take some photo through a loupe.
I also did some test on EDTA-acetic acid-peroxide bleach. I will post the result when the film is dry.

 

[Raghu Kuvempunagar]

Some update on my EDTA experiment:

I added various amount of EDTA to the phthalate-peroxide bleach. Interestingly this seemed to increase the rate of bleaching and reduce staining. Blistering is also reduced.

Interesting results! Looks like the ugly brown stain was also cut down by the addition of EDTA. Last strip, one that used highest amount of EDTA in your experiments, looks the cleanest.

Also interesting is the role played by PHP. Apart from acting as a pH buffering agent, is it also working as a stabilizer for peroxide?

 

[kentanghk]

Interesting results! Looks like the ugly brown stain was also cut down by the addition of EDTA. Last strip, one that used highest amount of EDTA in your experiments, looks the cleanest.

I see some stain-reducing effect of EDTA on acetic acid-peroxide bleach too. Hopefully we can formulate some usable peroxide bleach with EDTA or HEDP.

 

[kentanghk]

For acetic acid-bleach, I repeated the experiment with following bleach formula from Konica patent.

Hydrogen peroxide (35%) 50ml/L
Glacial acetic acid 40ml/L

The bleach was split in four and EDTA disodium dihydrate was added to reach following concentrations.
1. 0g/L
2. 0.28g/L
3. 0.57g/L
4. 1.40g/L

pH adjusted to pH4 by NaOH

This formula works much slower, probably due to lower hydrogen peroxide concentration. This is how the film looked after 5 minutes of bleaching

After 10 minutes

After 20 minutes

I stopped the bleaching at 20 minutes. The film was fixed, washed and dried. Brown stain was observed on all film strips.

They look really bad and I tried increasing the peroxide concentration to 3%. The result is much better in term of staining. I will post the result later this afternoon.

 

[Raghu Kuvempunagar]

This formula works much slower, probably due to lower hydrogen peroxide concentration.

You may want to use this particular bleach 24 hours after preparing as peracetic acid formation is not instantaneous and there's a study that shows that even at higher concentrations of peroxide and acetic acid, the reaction takes a few hours to produce useful amounts of peracetic acid.

 

[kentanghk]

I repeated the experiment with following formula.

Hydrogen peroxide (35%) 86.7ml/L
Glacial acetic acid 40ml/L
EDTA disodium dihydrate 0.57g/L

This bleach works much faster and it appears to complete bleaching in 2 minutes. Here is how the film looked after 5 minutes of bleaching.

After 10 minutes

Fixed, washed and dried.

I bleached a strip of film with dichromate bleach for comparison. Looks like both peroxide bleach cause slight sepia staining.
From left to right: dichromate, EDTA-phthalate-peroxide (2.2g/L EDTA), EDTA-acetic acid-peroxide (3% peroxide)

 

[kentanghk]

You may want to use this particular bleach 24 hours after preparing as peracetic acid formation is not instantaneous and there's a study that shows that even at higher concentrations of peroxide and acetic acid, the reaction takes a few hours to produce useful amounts of peracetic acid.

Thanks I might try the peracetic acid version to compare.

 

[Raghu Kuvempunagar]

I bleached a strip of film with dichromate bleach for comparison. Looks like both peroxide bleach cause slight sepia staining.

Konica patent has a stain removal bath after second development, IIRC. Maybe a short bleach in dilute Ferricyanide followed by fixing will can remove this stain.

 

[Raghu Kuvempunagar]

Thanks I might try the peracetic acid version to compare.

You should definitely. BTW this is already looking promising, at least for the film you tried it on. Good work.

If HEDP/EDTA can be substituted by Calgon (sodium hexametaphosphate), it'll be even more useful for some people who don't have easy access to the former chemicals.

 

[kentanghk]

Konica patent has a stain removal bath after second development, IIRC. Maybe a short bleach in dilute Ferricyanide followed by fixing will can remove this stain.

Thanks for pointing out the stain removal bath. I have completely overlooked it when I first read the patent. The stain removal bath look like some sort of rehalogenising bleach. Maybe the stain is caused by unbleached silver? This is interesting and I will try if flexicolor bleach can remove the stain.

 

[kentanghk]

Also interesting is the role played by PHP. Apart from acting as a pH buffering agent, is it also working as a stabilizer for peroxide?

I have seen reports on phthalic acid and its derivatives for stabilisation of hydrogen peroxide. I guess potassium hydrogen phthalate probably has similar stabilising effect?

 

[Raghu Kuvempunagar]

Thanks for pointing out the stain removal bath. I have completely overlooked it when I first read the patent. The stain removal bath look like some sort of rehalogenising bleach. Maybe the stain is caused by unbleached silver? This is interesting and I will try if flexicolor bleach can remove the stain.

The stain is probably silver. I read somewhere that during the bleaching of silver by peroxide bleach, some of Ag+ formed gets reconverted to Ag. However, this reconversion doesn't happen image wise as the silver ions would have moved out of place within the gelatin and hence it appears as ugly non-image stain.

 

[Raghu Kuvempunagar]

This is interesting and I will try if flexicolor bleach can remove the stain.

I would guess even a dilute Farmer's reducer would work well for this purpose when used after the second developing of the film.

 

[relistan]

@kentanghk That's very nice work! Thanks testing that out. Also feeling good that we wer right about the EDTA!

I got my bag of EDTA on Weds and will try it out. My hunch is that it might work without the other acid at all. Or possibly without the other acid, but with one of the accelerators from the Konica patent. I will also try it with the bleach I have been using since you already tested the other dilutions.

The lack of staining is very good and I'm interested to see how much less blistering there is!

Konica patent has a stain removal bath after second development, IIRC. Maybe a short bleach in dilute Ferricyanide followed by fixing will can remove this stain.

It does have a stain remover, but as I quoted earlier in the thread, they did not find it necessary with the supplied bleaches.

I would guess even a dilute Farmer's reducer would work well for this purpose when used after the second developing of the film.

Yes, I had this same thought. It would need to be very dilute to not affect the rest of the image.

I have seen reports on phthalic acid and its derivatives for stabilisation of hydrogen peroxide. I guess potassium hydrogen phthalate probably has similar stabilising effect?

I am guessing you are ending up with phthalic acid when it dissolves and this is one of the acids from the Konica patent. I think you are right that it is acting to stabilize the peroxide, possibly to prevent the runaway reaction that we see sometimes.

You should definitely. BTW this is already looking promising, at least for the film you tried it on. Good work.

If HEDP/EDTA can be substituted by Calgon (sodium hexametaphosphate), it'll be even more useful for some people who don't have easy access to the former chemicals.

I picked EDTA originally because it's very easy to get, I think just about anywhere. I only have one source for Calgon Photo that I know about in Europe (Suvatlar/Moersch) but EDTA I just ordered in a 1 kilogram bag delivered. It's used in tons of cleaning products and detergents. HEDP is much harder to get. The brand name of EDTA that I ended up with is "Dissolvine Z". It is technical grade. I am guessing Kentanghk is using a better grade. We'll see how it works.

Thanks again for the great testing @kentanghk ! Exciting results

 

[relistan]

FYI if anyone is trying to buy EDTA in Europe, this is the place in Ireland that I got it: https://mistralni.co.uk/products/edta-ethylenediaminetetraacetic-acid-dissolvine-z

 

[relistan]

Calgon-Photo is Sodium Hexametaphosphate - regular Calgon used to be the same, but then changed to a different formulation - and it acts as a manganese sequestrant in acidified permanganate bleaches, making them last for much longer. It's one of these ingredients that often gets dismissed as being 'for water quality' when seen in an ingredients list, but there's an Agfa patent (EP1006408A1 - only in German as far as I can tell, apart from Google's automatically translated version) which shows that 20g/l is about optimal for preventing the manganese deposits appearing & extending the bleach life into weeks.

Just reading more about EDTA and it seems to also be commonly used to chelate manganese. Might be worth a shot in the permanganate bleach as well.

 

[Anon Ymous]

FYI if anyone is trying to buy EDTA in Europe, this is the place in Ireland that I got it: https://mistralni.co.uk/products/edta-ethylenediaminetetraacetic-acid-dissolvine-z

Interesting, this is the free acid, not a Na salt. This is very useful to those who would like to scratch mix some E6 bleach, combined with some ammonia, ferric nitrate and ammonium bromide.

Ah, bummer, they only ship to Ireland/UK