Reducing sugars, like glucose

alanrockwood · Dec 31, 2016

I am curious to know whether reducing sugars like glucose can be used to develop film.

It is well-known among chemists that certain sugars, such as glucose (but not sucrose) can reduce silver ions to metallic silver in certain reactions. This is the basis of Tollens' test for reducing sugars. This leads me to wonder whether glucose might be useful as a developing agent, either as a primary developing agent or as a component in a super additive pair, perhaps replacing ascorbate for example.

Alan Johnson · Dec 31, 2016

Yes, sugars were investigated by Darkroom Experimente and I did some work on them, see post 395 and the following discussion:
(there was a url link here which no longer exists)

Gerald C Koch · Dec 31, 2016

Yes, Pierre Glafkides mentions it is his book. In addition many other strange compounds.

alanrockwood · Dec 31, 2016

Alan, thanks for the link, and Gerald, thanks for the comment.

Regarding the splitting of sucrose into glucose and fructose, as mentioned in the discussion to which Alan linked, which discussed acid-catalyzed hydrolysis, there is also an enzymatic method using a disaccharidase (sucrase). The reaction conditions would likely be less harsh than the acid-catalyzed hydrolysis, but it is likely more expensive.

If glucose is an effective film developer, I wonder why it isn't widely used.

Harry Stevens · Dec 31, 2016

Not used because of HC 110, Rodinal, D 76 plus lots of other good reliable developers cheaply available to the film community .

alanrockwood · Dec 31, 2016

I might have at least a partial answer to my question of why glucose is not widely used as a developer. (This assumes that glucose can actually develop film.) Glucose can exist as several structural different forms. Most of them are cyclical. One is an open chain. Only the open form can act as a reducing agent. The open form exists at a concentration of less than 1% of the total. (https://en.wikipedia.org/wiki/Glucose#Open-chain_form), so at any given instant only a very small fraction of the glucose in the solution is available to reduce the silver halide in the emulsion to metallic silver.

The kinetics of ring opening can also figure into the picture, but I haven't found information on that topic yet, but even in the best case (if the ring opening process is fast) only a tiny fraction of the glucose would be available at any given instant, so to be effective one would need to have a huge excess of glucose in the solution in order for the process to occur at a reasonable rate.

Another possibility is that glucose could act to regenerate the main developer in a mixture (e.g. metol, phenidone, or para aminophenol). However, a lot of the same considerations would apply, i.e. only a small fraction of the glucose molecules in the solution would be available at any given instant, so a huge excess of glucose would be required for the regeneration process to be efficient.

Alan Johnson · Jan 1, 2017

alanrockwood said:
Regarding the splitting of sucrose into glucose and fructose, as mentioned in the discussion to which Alan linked, which discussed acid-catalyzed hydrolysis, there is also an enzymatic method using a disaccharidase (sucrase). The reaction conditions would likely be less harsh than the acid-catalyzed hydrolysis, but it is likely more expensive.

Enzyme as developer - others have wondered about this. What would be the ingredients?

Martin Rickards · Jan 1, 2017

Tollen's reagent (silver mirror test) is a specific test differentiating aldehydes from ketones and, of course, glucose is far from the only common aldehyde: there are also formaldehyde and acetaldehyde as well as even a form of vitamin B6. However, Tollen's reagent reagent reduces the unstable diamine silver complex to silver and photogtaphic emulsion is based on silver halides.

Ian Grant · Jan 1, 2017

Ilford used Glucose (Dextrose) in their Ultra Fine Grain developer ID-44.

Ian

alanrockwood · Jan 1, 2017

Alan Johnson said:
Enzyme as developer - others have wondered about this. What would be the ingredients?

My thought was to use an enzyme to split sucrose into glucose and fructose. The glucose and/or fructose would then act as developers. However, your thought regarding enzyme as developer is intriguing. I wonder if there are such enzymes.

Ces1um · Jan 1, 2017

Ha! When I first read the thread title I thought this thread was about someone's new years diet resolution!

alanrockwood · Jan 1, 2017

Ian Grant said:
Ilford used Glucose (Dextrose) in their Ultra Fine Grain developer ID-44.

Ian

Ian, that's very interesting. Do you know what was the main function of the dextrose in the Ilford ID-44?

alanrockwood · Jan 1, 2017

Ces1um said:
Ha! When I first read the thread title I thought this thread was about someone's new years diet resolution!

I probably need that more than a new developer.

darkroommike · Jan 1, 2017

Ian Grant said:
Ilford used Glucose (Dextrose) in their Ultra Fine Grain developer ID-44.

Ian

Out of curiosity I used the Google for "Kodak developers sugar" and found a reference in a very old "Kodakery" to table sugar in developers and another reference to using milk sugar as a preservative. I vaguely recall another instance using a sugar in a fine grain developer but can't find the reference right now. When I eliminated Kodak from the query I found references also using honey and molasses.

Ian Grant · Jan 1, 2017

alanrockwood said:
I probably need that more than a new developer.

When I get time I'll try and find the first references to the developer and see what Ilford say about the formula, I know it was replaced by ID-48 which is similar to Microdol.

Ian

jim appleyard · Jan 1, 2017

Somewhere in Anchell & Troop they mention a couple of devs that use sugar. I don't believe they go into anything about reduction, but they mention that the sugars will reduce emulsion swelling.

I'll try to find the page...

jim appleyard · Jan 1, 2017

Correction: The sugar is NOT used to prevent emulsion swelling.

From Anchell & Troop FDC, page 85: "HD Russell introduced two excellent formulas in the 1930's that never rec'd the attention they deserved, Kodak SD-4 and SD-5. The sugar in these formulas was added to supress development in the A bath."

There are two other fomulas in this section that use granulated (table) sugar. I've never tried these, but have always been curious.

Ian Grant · Jan 2, 2017

I seem to remember that the Sugar in SD-4 and SD-5 was added to increase the viscosity of Part A of the developers allowing the diffusion of the developing agent(s) into the emulsion by keeping developer in contact with the film, immersion time in both baths was quite short 2 mins in Part A then 2-3 mins in Part B. The Sugar is not there at 100g/l to suppress development because none takes place in Part A (in both developers), and Part A has no Alkali and is already acidified with Sodium Bisulphite to inhibit development and oxidation although the sugar also helps prevent oxidation. There may well be a reduction in emulsion swelling. SD-4 and SD-5 were specialist developers for high speed processing of motion picture variable density sound recording film, the work was published by Crabtree, Parker & Russell.

They did get plenty of attention at the time and form the basis of work on regular two bath development but without the sugar, in particular the Leica Two bath developer and Col. W.C. Symmon's DK20 Two bath developer, and then other divided developers.

Ian

jim appleyard · Jan 2, 2017

Ian, I may be splitting a hare here, but there is 10g of sodium sulfite in SD-5 and 100g in SD-4, so SOME developement takes place in A; not a lot maybe, but 2 min. worth.

Like I said, I've never used these so I don't what they're all about, just quoting the book and passing along info that may be of interest.

Ian Grant · Jan 2, 2017

jim appleyard said:
Ian, I may be splitting a hare here, but there is 10g of sodium sulfite in SD-5 and 100g in SD-4, so SOME developement takes place in A; not a lot maybe, but 2 min. worth.

Like I said, I've never used these so I don't what they're all about, just quoting the book and passing along info that may be of interest.

Jim, the Bisulphite is sufficient to make the Part A solutions Acidic so according to Crabtree (Kodak) no development can take place until the film enters Part B.

Alan, the references I have for use of Sugars, is to increase viscosity, slow development, help prevent oxidisation.

The Sucrose used in SD-5 and SD-5 has no reducing power however the Glucose (Dextrose) in ID-44 does but at 20g/l along with Salicylic acid it's not acting as a primary developing agent more likely as an anti-oxidant.

Ilford ID-44

p-Aminopheol Hydrochloride . . . . . . . . . . . . 5g
Metol . . . . . . . . . . . . . . . . . . . . . . . . . . . 4g
Sodium Sulphite (anhyd) . . . . . . . . . . . . . . 125g
Glucose (Dextrose) . . . . . . . . . . . . . . . . . . 20g
Salicylic acid . . . . . . . . . . . . . . . . . . . . . . 0.5g
Borax . . . . . . . . . . . . . . . . . . . . . . . . . . . 5g
Calgon (if needed) . . . . . . . . . . . . . . . . . . . 1g
Water to . . . . . . . . . . . . . . . . . . . . . . . . . 1 litre

p-Aminophenol was widely used by all the major companies in the UK/Europe. Ilford's equivalent of Rodinal "Certinal" was introduced in 1907, Kodak Ltd made Kodinol and published some "Metol free" developers here. Ironically Kodak's work was based on research by Mees and Sheppard when they were at Wratten and Wainwright, a few years before their joining Eastman Kodak to found the Research Labs and the purchase of Wratten and Wainwright.

Ian

jim appleyard · Jan 2, 2017

OK, thanks Ian.

alanrockwood · Jan 5, 2017

Thanks Ian.

Reducing sugars, like glucose

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