Hydrogen Peroxide as a developer additive?

Recently, on another forum somebody asked about Edwal FG-7 developer, and this

got me thinking about my only experience with it. Several years ago, I worked

in black and white lab, and we had a client who requested his film developed in

FG-7, mixed with a low solution of hydrogen peroxide. I think it was 7% or 10%

hydrogen peroxide, something like that. Anyway, this guy was an old pro and a

known name, somebody who's been around a while and knew what he was doing- not a

total nut case. In any case, the film (HP5+) came out looking pretty good. I

was thinking about this today, and wondering if anyone could explain the reason

for this, or what the hydrogen peroxide does? What's the chemistry behind this?

Is it specific to this developer? Anyone with any experience with this? I

know I could reproduce the results, test it against a control without the

hydrogen peroxide, and see for myself what it's doing, but I'd like to know why

it works, and what it's really doing. Thanks for your input.

I haven't heard of that, but I was just looking at the Darkroom Cookbook (Handbook?) and they mentioned using hydrogen peroxide on a cotton ball at the bottom of a tank and fuming the exposed film prior to development as a way to push the film. I really don't know why it works.....H2O2 is a great bleach and oxidizer, though.

Here's a pretty detailed discussion of one H2O2 push technique:

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=007Vfk

Hydrogen peroxide /in/ a developer seems to me like a great way to destroy the developer. The hydrogen peroxide would annihilate the sodium sulfite first, oxidizing it to sulfate, and then whatever was left would probably set to work on the metol, hydroquinone, ascorbic acid, phenidone, or any other easily oxidized materials in the developer.

Hydrogen perioxide in higher concentrations is unstable- it quickly breaks down to form water and oxygen. Even the hydrogen peroxide sold at drugstores will decompose easily even though it is typically a 3% solution. As a science experiment we used to mix the paste from old dry cells with it to make oxygen. If it breaks down in the developer you might get a lot of small bubbles which could stick to your film. But if you try it, be sure to post some results.

The technique I think you have heard of is 'peroxide hypering', a method of increasing the film speed. However, if you simply add peroxide to a developer you will ruin it completely.

Oddly enough both Mees and Mason mention hydrogen peroxide as one of the few inorganic developing agents ? albeit a weak one, and only in strongly alkaline solutions.

 

Why don't you try it, and tell us what happens.

 

Best, Helen

Oh, and Mees likens the structure to hydroquinone. Well, in a very limited way.

Helen,

 

I'm mystified by this. All developing agents that I know of are mild reducing agents, hydrogen peroside is an oxidising agent and a quite vigorous one at that. Could you please direct me to the info in Mees and Mason which refer to peroxide as a developeing agent? I am intrigued to know more.

Hi Chris,

 

Hydrogen peroxide can act as a reducing agent in certain circumstances. The oxygen is oxidised to free oxygen. I'll dig out the references in Mees and Mason.

 

Best, Helen

Hydrogen peroxide is generally only available in 3% solution, but is available at higher concentration (30%) to qualified research institutions. At higher concentration, it is a liquid that is violently unstable and dangerous to use.

 

Peroxides are patented by Kodak and Agfa for use in color developers as catalytic agents in dye formation. They react very slowly with developing agents, but the reaction is speeded by a catalytic metal surface. I have not seen or heard of the reports that Helen mentions above, but I suppose it might work. Although, offhand IDK how.

 

I have done extensive work on catalytic color imaging, but none in B&W imaging.

 

Super sensitization using hydrogen peroxide has been well known, but cannot be applied post-exposure.

 

Ron Mowrey

The darkroom cookbook also mentions this:

 

page 66.

 

Interesting stuff

 

Google has a huge chunk of the book online:

 

http://books.google.com/books?id=3ZN5sEjAWDEC&pg=PA66&lpg=PA66&dq=pushing+film+with+hydrogen+peroxide&source=web&ots=yyEdI3D0Lr&sig=YfrXBBlBvVu616kfUBrIfJBn0Dw#PPA66,M1

Here are some references to the use of hydrogen peroxide as a developer, _not_ as a developer additive or as a 'speed-increasing' afterbath.

 

Haist, Modern Photographic Processing (1979), Vol 1, p162

 

under 'Kendall Rule'

 

"When n=0, the Kendall formula becomes A-A' ; that is, the two functional groups are connected to each other without any intervening carbon atoms. Three simple possibilities exist:

 

(hydrogen peroxide, hydroxylamine and hydrazine)

 

These compounds have found limited use in photography. Hydrogen peroxide is a weak developer at moderate solution alkalinities."

 

Cites an 1894 French paper by Le Roy and an 1899 German paper by Andresen.

 

Mason, Photographic Processing Chemistry, 2nd Ed (1975), p16

 

"Hydrogen peroxide functions as a weak developer in strongly alkaline solution, but there is much spontaneous decomposition of the peroxide on the developing silver."

 

Hydrogen peroxide and the perhydroxyl radical (HO2) get mentioned again as products of the aerial oxidation of hydroquinone, and it is suggested that the perhydroxyl may be responsible for aerial fogging. Latensification by hydrogen peroxide and by perborates etc is also mentioned.

 

Mees (Ed), The Theory of the Photographic Process (1954 edn), "The Developing Agents and Their Reactions" by A Weissberger, p 540

 

"Hydrogen peroxide, hydroxylamine and hydrazine are particularly interesting nonmetallic inorganic developers because they can be considered the direct combinations of the effective groups of the most important organic developers. Hydrogen peroxide acts as a developer in rather strongly alkaline solution. It does not develop in the absence of alkali. The reductant proper is obviously an anion. Sheppard and Mees found that one mol of hydrogen peroxide reduces one gram-atom of silver to the metallic state and that the gas evolved contains 2 to 5 percent of hydrogen. Later investigations show that the radical HO2 is a carrier in the decomposition of hydrogen peroxide. It is interesting to note how far the analogy between hydrogen peroxide and hydroquinone extends. Molecular oxygen corresponds to quinone which is formed by the oxidation of hydroquinone; and perhydroxyl corresponds to semiquinone which is an important intermediate in this process. Oxygen and hydrogen peroxide or its ions, however, do not react with each other as hydroquinone and quinone do..."

 

L P Clerc's Photography Theory and Practice, Vol 4, Monochrome Processing, Section 529. Inorganic Developing Agents.

 

"Non-metallic inorganic reducing agents such as hydrogen peroxide, hydroxylamine, hydrazine and sodium dithionite are rarely used other than for academic studies."

 

James and Higgins, Photographic Theory (1948) p89 also mentions hydrogen peroxide as a developer "under more restricted conditions" [than hydroxylamine].

 

Hydrazine is frequently mentioned as a developer additive, by the way.

Helen,

 

Many thanks for that. This has been a very informative thread.

Thanks Helen. I completely missed that in Haist.

 

I might note that hydrazine has been used as a reversal (fogging) agent in reversal film processing. This is due to its poor nature as a developer.

 

And the evolution of oxygen by peroxide on the developing silver image is exactly what leads to heterogeneous catalytic color image formation. See Bissonette, Hutteman and Mowrey, ICPS proceeding 1978 and corresponding patents.

 

In other words, peroxide is weak becuase it self destructs more rapidly than it develops the image and it does it on the silver it forms. The other agents work but fog badly.

 

Ron Mowrey

You can pick up 30% hydrogen peroxide at your local hydroponics grow shop. It's used to sterilize equipment and as an additive (in very small amounts!) and as a way to boost oxygen levels when growing in soil.