Acetone in lith developers

[grainyvision]

Has anyone tried acetone in the context of lith developer formulation and have any guidance on it? Last night I made some acetone-sulfite addition product last night and a small test solution using what was left on the spoon. The test solution was just the bit of the product left on my spoon, a pinch of hydroquinone and a dash of potassium carbonate. This solution only slightly discolored this morning when I checked it. A test using just acetone went dark brown after just a few minutes. I also tested sodium metabisulfite added directly to acetone without water, which did not seem to react and the sulfite seemed insoluble. I already know a good amount of sulfite would stabilize it, but also compromises the infectious development effect.

While I wait on this addition product to dry, how should I even use it? I have the equivalent of ~65g of sodium metabisulfite tied up into the addition product, so I have a good amount for testing. I'm unsure if making this addition product was actually necessary to make and isolate in the first place, or if adding sodium sulfite and acetone to water would've been good enough. (I'm always looking for an excuse to have fun with chemistry though, so I don't mind lol). Also though I understand the equilibrium reaction, I'm unsure how to keep "the equivalent of 1g of active sodium sulfite and a surplus of 4g of inactive sodium sulfite" in solution... or if acetone would be stable in alkali like would be expected in a lith developer working solution, or acid as would be expected in the lith developer concentrate (part A)

 

[koraks]

Isn't the acetone supposed to break down and create hydroxide in a typical lith formula? I'm rusty on the subject, but I've read about it quite a bit when I was messing around with lith and ultimately decided it just wasn't worth it. I just have tried adding a dash to a lith developer, but I never saw any magic.

 

[grainyvision]

Isn't the acetone supposed to break down and create hydroxide in a typical lith formula? I'm rusty on the subject, but I've read about it quite a bit when I was messing around with lith and ultimately decided it just wasn't worth it. I just have tried adding a dash to a lith developer, but I never saw any magic.

I did a test run and confirmed it has some kind of potential, but balancing a developer properly to use it is not greatly trivial. My test developer used far too much sulfite and too high of working pH to compensate for it. I confirmed that adding excess acetone to the developer increased activity of the developer and importantly seemed to increase infectious development rate and depth. End result being faster development and deeper blacks.

I'm unsure why there is posts on here saying that acetone (or formaldehyde) addition products with sulfite "make a lith developer better because when it breaks down it releases alkali", but that is not how it works, or if it is then it is not a great contributor to the lith effect, especially considering the addition product is actually an acidic bisulfite in both cases. Breakdown releases acid, not alkali. This is why pure hydroxide buffer systems in lith developers are more greatly unstable with formaldehyde than without and are not often used.

 

[ruilourosa]

Tim rudman is the reference on lith printing...
Check his book!

 

[grainyvision]

Tim rudman is the reference on lith printing...
Check his book!

He has never formulated his own developer so while his writing on procedures are great, there is no guidance on forming a lith developer formula

 

[Nikola Dulgiarov]

Carbonyl groups are able to react with the sulfite ion, thus forming the bisulfite adduct, the hydroxysulfonate, and free hydroxide. This is an equilibrium process, so it is pH dependent and the subsequent adducts have different stability constants.
So, to compare, in the table below are the logK constants of formation for some carbonyl compounds. The second column lists the pKa. Notice that formaldehyde-bisulfite is about about 30 million times more stable than acetone-bisulfite (logK 9.83 vs 2.36).

So, it is true that adding an aldehyde or a ketone to a sulfite or bisulfite solution will form the adduct and raise the pH. However, formaldehyde is much, much more reactive in that respect and can effectively tie up sulfite ion in a developer, whereas acetone would only work in substantially higher concentrations. The acetone adduct is fairly water insoluble, so if you're working in the right concentration range, you'll get a precipitate.

To break down the bisulfite addition product, when it is used in a preparative fashion, it is mixed with acid and distilled. This drives the equilibrium in the reverse direction, both because the acid raises the free H+ concentration and because the distillation will remove the free CO compound.

In practical terms, there was a formula floating around, maybe in the recipe section (Jekyll's Lith or something like that). It used HQ, sulfite + acetone, carbonate, and noniodized salt. It worked OK as a lith developer, though i didn't find that the acetone per se changed much about its working properties or life.

 

[grainyvision]

Carbonyl groups are able to react with the sulfite ion, thus forming the bisulfite adduct, the hydroxysulfonate, and free hydroxide. This is an equilibrium process, so it is pH dependent and the subsequent adducts have different stability constants.
So, to compare, in the table below are the logK constants of formation for some carbonyl compounds. The second column lists the pKa. Notice that formaldehyde-bisulfite is about about 30 million times more stable than acetone-bisulfite (logK 9.83 vs 2.36).

So, it is true that adding an aldehyde or a ketone to a sulfite or bisulfite solution will form the adduct and raise the pH. However, formaldehyde is much, much more reactive in that respect and can effectively tie up sulfite ion in a developer, whereas acetone would only work in substantially higher concentrations. The acetone adduct is fairly water insoluble, so if you're working in the right concentration range, you'll get a precipitate.

To break down the bisulfite addition product, when it is used in a preparative fashion, it is mixed with acid and distilled. This drives the equilibrium in the reverse direction, both because the acid raises the free H+ concentration and because the distillation will remove the free CO compound.

In practical terms, there was a formula floating around, maybe in the recipe section (Jekyll's Lith or something like that). It used HQ, sulfite + acetone, carbonate, and noniodized salt. It worked OK as a lith developer, though i didn't find that the acetone per se changed much about its working properties or life.

Where did this chart come from? I found a patent which gives some similar info, but not in this form. I've tried cinnemaldehyde a year ago for similar purposes to acetone, but unfortunately I couldn't figure out a carrier solvent to actually get it into solution, it is oily and also very smelly (even if that smell is like Christmas rather than a nail salon lol). There's some research that cinnemaldehyde also reacts with sulfite, but I have no idea how to introduce the two since sulfite is insoluble in it.

Benzaldehyde might be interesting, but it's solubility in water looks to be quite limited. Most other chemicals I found that have this kind of reaction are either unworkable for safety reasons (no one is going to work with a pungent liquid that boils at 20C), nor a chemical that forms chloroform in alkali, or simply that it is very difficult to source for home use, such as cyclohexane. Acetone appears to be the best thing to use, even if it's reaction is greatly less than formaldehyde. Besides, I am not looking for a magic bullet that will beat formaldehyde in terms of preserving ability. Rather I am looking for something to allow the "modern lith" effect with more than 1 hour of tray stability. Many modern papers ARE lithable, despite what is commonly said in discussions on the topic, but it requires a specific set of developer properties: very low sulfite (~30% less than common lith developers), high hydroquinone (10-20% more), slightly higher pH (best pH is around 11-11.5, rather than 10.5-11), and very low bromide (~50% less). If I can make something that will last for 2-3 hours, not be greatly noxious to use, and still get this effect, I'd be happy.

In regards to the acetone addunct, I've not observed an issue with water solubility. I plan to use a 2 part formula with the acetone separate from the sulfite to avoid dealing with any of this anyway, but I had no issue dissolving around 2g of the product in 100ml of water without issue, it went into water almost immediately.

The test developer I formulated had this as a working solution:

* 600ml water
* 4g sodium metabisulfite
* 0.1g borax
* 2.2g hydroquinone
* 6ml propylene glycol (used as solvent for hydroquinone)
* ~10g potassium carbonate
* ~2g potassium hydroxide (pot carbonate and hydroxide were added as needed to bring pH to around 11.5
* 0.5g potassium bromide
* 1ml of 1% PEG-3350 in water (MiraLAX, contrast modification agent)
* 6ml acetone (additional 10ml added in test below)

The amount of sulfite used was prohibitive even with a relatively large amount of acetone, but I was able to make some prints. Below is my test print for this. Kodabrom II RC, a vintage lithable paper. The top print is with 10ml additional acetone, the bottom is with the developer described above. Both prints were developed for 7.5 minutes. The top print has much better black depth than the bottom, but I have seen much better depth with other formulations. I also tested Ilford MGV (poor black depth) and Fomatone Classic FB (decent and usable, but black depth was not as great as other developers I've formulated)

 

[Nikola Dulgiarov]

Ashley, if you want to know the effect of acetone in the lith formula, prepare it without acetone and divide in three separate batches (no acetone, 10ml/L acetone, 50ml/L acetone), then measure the pH and adjust them all to the same alkalinity with hydroxide. Since acetone reacting with sulfite raises the alkalinity, unless you buffered the solutions after the ketone addition, the test above indicates that a higher pH developer is more active, but not much about the effect of CH3COCH3.

Testing with a proper control will give you more information. I think that more than 10ml of acetone per L developer will be needed to show the sulfite sequestration effect, simply because the kinetics of the reaction are not favorable.

 

[grainyvision]

Ashley, if you want to know the effect of acetone in the lith formula, prepare it without acetone and divide in three separate batches (no acetone, 10ml/L acetone, 50ml/L acetone), then measure the pH and adjust them all to the same alkalinity with hydroxide. Since acetone reacting with sulfite raises the alkalinity, unless you buffered the solutions after the ketone addition, the test above indicates that a higher pH developer is more active, but not much about the effect of CH3COCH3.

Testing with a proper control will give you more information. I think that more than 10ml of acetone per L developer will be needed to show the sulfite sequestration effect, simply because the kinetics of the reaction are not favorable.

I've observed that despite expectations, acetone can function as a restrainer, but that might be due to a superadditive effect with PEG-3350. I've been able to make a developer mixture which stayed alive far longer than a low sulfite version, but the pH of the acetone version must be quite high. I'll do a control test later to bring ph to similar range but with no acetone

 

[grainyvision]

I was going to do the control test later but decided to do it this morning. The results are very interesting. Prototype formulas:

GVXC1 Prototype #2:
Part A:
* 40ml water
* 9.4g potassium metabisulfite
* 2g sodium sulfite
* 0.3g borax
* 11g hydroquinone (make a slurry, will not dissolve)
* 30ml propylene glycol (solvent for hydroquinone)
* Top to 100ml with water

Part B:
* 50ml water
* 8ml of potassium metaborate 50% solution (probably not necessary, equivalent to about 10g sodium metaborate)
* 36.5g potassium carbonate
* 2g potassium bromide
* top to 100ml with water

Working solution tested:
* 600ml water
* 20ml A
* 20ml B
* 10ml 20% potassium carbonate (previous testing shows too little alkali)
* 15ml 10% sodium hydroxide

The ending pH is about 12, measuring by pH test strips so accuracy is poor.

I made 2 prints with this solution, each with the specific aim to develop until a particular spot on the print turned deep black:
* Kodabrom II RC (lithable): Produced a print in about 3.5m. Overall contrast was poor and highlights overly darkened. Deep black tones are present. coloration was neutral
* Ilford MGV RC ("unlithable"): Produced a print in about 3m. Overall contrast was poor and appeared to be grossly over exposed with highlights and midtones both were far too dark. Deep black tones were present. Coloration was slightly warm browns.

I then added two small pinches (~0.5g) citric acid to the solution and then added 20ml of acetone. Then I developed 2 prints using the same exposure, aim, and papers as above
* Kodabrom II RC(lithable): Produced a print in about 2.5m. Overall contrast was poor and was similar to the previous result, but with slightly brighter highlights. Coloration was slightly warm brown
* Ilford MGV RC(unlithable): Produced a print in about 5.5m. Overall contrast was excellent with bright highlights and deep black shadows. Coloration was bright orange highlights and cold brown shadows and deep cold blacks.

The difference between how fast a lithable vs unlithable paper develops depending on acetone content I believe shows that something much more important than a simple pH modification is happening by adding it. In addition I've tried to a variety of pH values and additives with Ilford MGV RC and I've never been able to get a result like this with it. With low pH, black tones will not properly develop. But with high pH, highlights and midtones will be over developed resulting in a loss of the lith printing style of contrast control. An additional interesting observation. Acetone may have gelatin hardening properties like formaldehyde. I don't have a way to really measure it, but using Foma Retrobrom, in most lith developers the emulsion is very obviously swollen feeling very slippery and even appearing extra thick. In the acetone containing developer, this did not seem to happen to at all the same extent. I also was able to get reasonable results with it, whereas with other formulations I typically have contrast issues on retrobrom.

Ilford MGV RC example attached below, the top print is the one with acetone, the bottom is without:

Edit: For anyone reading along at home, I found the article referenced above. Rate constants for formation of bisulfite addition compounds: an examination in terms of No Barrier Theory. Canadian Journal of Chemistry, 93(2), 227–233. doi:10.1139/cjc-2014-0270

 

[grainyvision]

I decided to do some testing with some "household" aldehydes. First I tested a similar mixture as above, but instead of acetone I used 30ml of natural vanilla extract. There was a small difference and increase in contrast, but it was minor. The natural stuff I expect could contain chemicals which could function as secondary developing agents as well, so is non-ideal. Considering the cost of vanilla, I think it is prohibitive to use natural. Will try artificial (vanillin) later.

Extremely interestingly though, I also had a few drams of cinnamon oil left over from the last time I had a similar itch. This time I decided to approach it a bit more scientifically and used 1 entire dram and a matching amount of ethanol (everclear). Although this solution seemed to combine without issue, upon adding it to water oil quickly separated from the solution. It did not appear to be the yellow cinnamon oil though and instead was an oil which was white in appearance. A small amount of oil floated on top of the solution, but interestingly a strange insoluble soap formed on the bottom which smelled very strongly of cinnamon and could not be removed, even with sulfuric acid. The oil in solution was also impossible to extract. I decided to try using this mixture despite the oil issue and surprisingly it gave a significant lith effect improvement. In fact, it was so strong that the developer was somewhat unstable and upon standing would turn brown in spots, identical to how a very low sulfite lith developer would behave at high pH. Unfortunately cinnemaldehyde is not as easily available as would be expected, though I did find a reasonable source which is not prohibitively expensive. I'm hoping that "pure cinnamon oil" and "cinnamaldehyde" are not exactly the same and maybe the latter I can form some solvent system with to keep in solution. Making soap within a developer is not a fun thing.

I'm also trying a few other easily available and (mostly) non-toxic aldehydes and ketones. I'm hoping I can find something which maybe hasn't been researched which would be an ideal replacement for formaldehyde. While acetone definitely works, I expect there to be better substitutions available

 

[Nikola Dulgiarov]

Interesting results, you are approaching the acetone content of previously published formulas, so it seems reasonable that amounts up to 5-10% v/v could be used without degrading the emulsion or other side effects. Ketones do not react with gelatin the same way formaldehyde or the dialdehydes do to produce a hardening effect. It cold be a solvent surface effect messing with the surface tension or something similar and temporary.

What was the purpose of the citric acid added along with the acetone? pH control I guess, but it would be better to use a strong acid like sulfuric, or barring that, at least a monoprotic like acetic acid, and in a stoichiometric amount to the hydroxide expected to be formed with the addition of a ketone, if you are trying to control that variable.

Re other aldehydes: the problem with them in alkaline solution, besides the poor solubility in water overall, is that they undergo aldol reactions, forming condensation products, which may have unknown photographic effects. Since formadlehyde doesn't have an alpha carbon to be attacked, it is in a way immune to aldol mechanisms, and its high reactivity with sulfite means it gets quickly sequestered. Other aldehydes aren't as lucky in either respect.
Although formalin toxicity is real and not to be snubbed, in a properly formulated lith developer, most of it is tied up in the bisulfite adduct. To avoid handling the concentrated solution, paraformaldehyde is available, which is basically a polymer of formadehyde which decomposes in alkaline conditions to the free species, which can then react with sulfite ion.

 

[Nikola Dulgiarov]

Recalling patents, it might be useful to add some amines in the devloper along with the acetone. IDK if triethanolamine would work, but it may be worth a shot, as well as increasing the amount of glycol in the working formulation, or switching to diethylene glycol. I think that any novel lith developer would avoid sulfite altogether. For conventional developers, it is difficult to use alternative preservatives, but in a dilute, high-pH formulation, it may be interesting to look at other antioxidants, such as propyl gallate.

 

[celgazer]

As the solution is highly alkaline, using citric acid to adjust pH can be practical, but the stoichemical amount should be considered carefully. When adding citric acid to control pH value, adding about 0.5 grams can be too much? Consider a 680mL working solution system (GVXC1 Prototype), there are about 20 mL (about 0.4mol/L) acetone and about 0.03M total sulfite present in this solution. The equilibrium constant for A(acetone) + SO32- + H2O === ASO3H- +OH- can be calculated with logK=-4.4 (logK2-pKw+pKa) based on the chart provided by Nikola.

Suppose there is no change in acetone/sulfite concentration during the reaction, and [OH-] is fixed to 0.01M (pH=12), just about 4.7x10^-5 mol/L of ASH- is produced at equilibrium. So, the excessive OH- produced during the adduct reaction should also be 4.7x10^-5 mol/L. It's a neglectable number comparing to 0.01M OH-. As a result, adding 0.5 grams of citric acid can really influence the developer activity, while adding 20 mL acetone to this system will not show any significant change in solution alkanity. As an organic solvent, acetone can really decrease the swelling of the emulsion. As the reaction between acetone and sulfite in working solution is not significant, the photographic activity of acetone here can be an interesting result.

For cinnamon aldehyde, it can be prepared by aldol reaction between benzaldehyde and acetaldehyde. However, as aldol reaction is reversible, the real species in solution can be much more complex. The double bond makes it highly reactive to different reactions or even form polymers. (Actually it can react with two eq. bisulfite to form an adduct, CAS RN. 105391-35-3, due to its alpha - beta unsaturated structure. ) It's also interesting to find cinnamon oil is active here. Maybe the real active species can be a little bit complex in this system.