Coffee Based Developers, Why?

[removed account4]

...

 

[Nicholas Lindan]

I can't find the catechol aisle at the supermarket.

It's in the fruit section:

http://www.ehow.com/about_4619323_catechol-in-bananas.html

Almost tempts me to brew up some bananol...

 

[mabman]

There is a note on the safety of Catechol on p135 of the Film Developing Cookbook.
Regarding sodium hydroxide see this:
www.ccohs.ca/oshanswers/chemicals/chem_profiles/sodium_hydroxide/

The newbie is safer messing with Caffenol I daresay.

This is one of the reasons why I tried Caffenol-C once; it was a way to experiment with a staining developer without any risk of accidentally doing harm to myself or others.

Also, as others have mentioned, for an experiment with staining developers it's much more cost-effective than importing the ingredients, pre-mixed or not (for me the local photo stores don't stock any pyro developers at all, and all chems would have to be imported as well).

That said, the Caffenol smell turned me off - I might try it again, but perhaps in a better ventilated area

I am currently experimenting with a similar staining developer made with very strong mint tea - less convenient (no instant mint tea that I've seen, so you have to brew it), but it smells much nicer.

 

[Gerald C Koch]

On looking over the posts I find that key bounce caused an error in the formula that I gave. The amount of water should be 200 ml not 220 ml for the working solution. The line should read "10 ml of A, 10 ml of B, and 200 ml of water. The formula is from Pierre Gllafkides "Photographic Chemistry", Vol One, (London:1958), p 74. Why 200 ml, I suspect that the directions are for sheet film. It is easy to scale up for roll film. The formula is for a compensating tanning developer.

For a general purpose catechol (pyrocatechin) developer there is the following formula on p 67.

Stock Solution A

Sodium sulfite, anhydrous 35 g
Catechol 12 g
Water to 500 ml

Stock Solution B

Potassium carbonate 60 g
Water to 500 ml

For use take equal parts of A and B.

For either of these developers the working solution should be made up just before use.

If you have been using caffinol and can obtain some catechol I would suggest trying a catechol developer. You may be quite happy with the results. Photographer's Formulary sells catechol for $37 a pound so its not terribly expensive. Smaller amounts are also available in 10 g and 100 g amounts.

 

[Steve Smith]

I am currently experimenting with a similar staining developer made with very strong mint tea - less convenient (no instant mint tea that I've seen, so you have to brew it), but it smells much nicer.

I have heard that an infusion of rosemary works too.


Steve.

 

[Gerald C Koch]

I have found the following suppliers of ascorbic acid. 1 in the UK

Artcraft (USA)
Photographer's Formulary (USA)
Silverprint (UK)
Tech Chem Inc (US)

 

[removed account4]

jd photochem closed last year

 

[Gerald C Koch]

Where is catechol readily available? Can it be substituted with Tylenol?

Sorry, Tylenol is another beast and is related to Metol. Catechol (1,2-dihydroxybenzene) is related to hydroquinone (1,4-dihydroxybenzene).

 

[ntenny]

I have heard that an infusion of rosemary works too.

This is on my to-do list (I have a hugely overgrown bed of rosemary in the front yard). Have you heard any indication of how *much* of the stuff is needed to get a reasonable concentration of developing agents? I don't know if I should be starting with a few sprigs or a bushel basket.

-NT

 

[Gerald C Koch]

jd photochem closed last year

Thanks! Couldn't find Rayco and AREM either. Was able to still edit the list.

 

[Gerald C Koch]

There were a couple of suppliers in Germany. Can't remember their names. Perhaps chemical suppliers in eastern europe.

With the decline in silver photography things will be getting worse,

 

[removed account4]

This is on my to-do list (I have a hugely overgrown bed of rosemary in the front yard). Have you heard any indication of how *much* of the stuff is needed to get a reasonable concentration of developing agents? I don't know if I should be starting with a few sprigs or a bushel basket.

-NT

a few years back ( 07' ) darkroomexperimente started a thread about edible developers

(there was a url link here which no longer exists)

page 6 has info on rosemary, parsley and a few others

 

[Gerald C Koch]

There is also isoascorbic (erythorbic) acid and sodium isoascorbate (sodium erythorbate). This chemical is an isomer of ascorbic acid and has a slightly higher developing activity. Both the acid and the sodium salt are used extensively in food manufacture as an antioxidant. In the US it is cheaper than ascorbic acid. I have bought sodium erythorbate from a company that sells various spices and flavorings Sutton Bay Spice, www.suttonbayspice.com. Check for a similar supplier in Europe. Since it's considered a food additive it might be easier to obtain. Sutton Bay lists it under sausage supplies. They also sell citric acid.

 

[jon.oman]

Well, I was going to try caffenol, now maybe I should go the catechol route?

 

[CBG]

... I am curious as to why people bother with such developers...

There is something fascinating about the idea that simple household substances can work the magic of developing film. No matter the limitations of coffee based mixes vs D76 or xtol, they are still interesting.

 

[ntenny]

Catechol (1,2-dihydroxybenzene) is related to hydroquinone (1,4-dihydroxybenzene).

I hadn't realised this. How is it, then, that hydroquinone is such nasty stuff (contact dermatitis, problematic pollutant, &c.), while the catechol in bananas and the catechol relative in coffee are seemingly benign? Does relocating the one hydroxyl group make that much difference, or is hydroquinone overrated as a chemical horror?

-NT

 

[grommi]

Interesting thoughts. In Germany you can buy Brenzkatechin (Catechol) at
http://www.omikron-online.de/cgi-bin/cosmoshop/lshop.cgi
1 kg for 90 Eur, 250 g for 28 Eur f.e.

So developimg costs will be roundabout the same as for Caffenol-C based upon prices in Germany. And Catechol is regarded to be quite toxic.

But it's not at all clear that caffeic acid is the only developing agent of coffee. Surely it's one agent, but so many other different things in there.

@ Gerald: 13 or 14 stops subject contrast range handled with Caffenol-C? Try once in your life Acros100 in Caffenol-C and you will see what we are talking about.

Best - Reinhold

 

[Hexavalent]

I hadn't realised this. How is it, then, that hydroquinone is such nasty stuff (contact dermatitis, problematic pollutant, &c.), while the catechol in bananas and the catechol relative in coffee are seemingly benign? Does relocating the one hydroxyl group make that much difference, or is hydroquinone overrated as a chemical horror?

-NT

Catechol occurs naturally in bananas etc., in very small amounts. In the pure form, catechol is not benign: LD50 similar to hydroquinone. Resorcinol, another isomer of benzenediol is similarly irritant and toxic.

Although relocation of a hydroxyl group looks rather trivial in a 2D diagram, there can be significant changes in chemical, and particularly biological activity.

 

[CBG]

... How is it, then, that hydroquinone is such nasty stuff ... ?

One needs to exert an effort to get a fair view of photo chemicals. If you read up on them on the net or read the MSDS sheets, many chemicals look like some sort of "executioner in a bottle". Most that have that sort of scary description fail to live up to their fear factor when seen in their actual practical and responsible photographic usage. Then again, there are lots of chemicals that are truly dangerous to use. So sorting them out isn't simple.

Hydroquinone is neither as benign as some say, nor as nasty as others would argue. It has been used worldwide for many decades as one of the most common developing agents used in developer formulas. It has not caused an epidemic of dead darkroom workers. It is pretty safe in the modest amounts seen in developers when used with very moderate precautions, i.e. don't eat it or drink it or breathe it in. When mixing it, don't shake the powder into the air. Get it into the water.

Health studies of the photographic industry would seem to have born this out; what I have read indicates photographers and darkroom workers have had no excess health issues when compared to the population as a whole. I would guess that it is the very rare darkroom worker who has never used hydroquinone.

In the hundreds of formulas I have collected off the internet and from books, roughly one third of them incorporate hydroquinone. D-76 and Dektol, the two most used and most standard developers ever, both use hydroquinone and metol. By the way, metol is far more often identified as a cause of health reactions in actual users from skin reactions commonly named metol poisoning.

Hydroquinone is not utterly benign. It is now understood to be environmentally undesirable and as such is being phased out of many products. It was at one time a component in cosmetic products. While someone, somewhere, I am sure, must have been adversely affected by ordinary and careful photographic use of hydroquinone, I have never heard of it.

 

[Trask]

I think hydroquinone was in some men's hair dye I tried several years ago -- and no, I'm not still using it, such a pain it was. Maybe that's why I have black-and-white photography on the brain.

PS, the link is to http://www.suttonsbayspices.com/ -- the final "s" in spices got dropped in the previous reference.

 

[23mjm]

I hadn't realised this. How is it, then, that hydroquinone is such nasty stuff (contact dermatitis, problematic pollutant, &c.), while the catechol in bananas and the catechol relative in coffee are seemingly benign? Does relocating the one hydroxyl group make that much difference, or is hydroquinone overrated as a chemical horror?

-NT

Welcome to the wonderful would of chemistry---take something like Chlorine, you have the Cl- ion humans need it for life, combine it with the Sodium ion and you have a tasty seasoning, salt. Combine the same Cl- ion with a H+ ion and you get HCl add water and you get Hydrochloric acid--not so tasty. Take Chlorine gas Cl2 also not so tasty. A very small change in a chemical formula can have profound changes in what a chemical does.

 

[Gerald C Koch]

Many chemicals used in photography are toxic but the point is that you are not eating or bathing in them. Hydroquinone was used in creams used to bleach age spots on the skin. Catechol has a small vapor pressure which means that it slowly sublimes at room temperature. One should be careful not to breath the vapor from the solid for an extended[/U/ period of time.

It is not only the poison it is also the dosage. Large doses of vitamin A are poisonous and can kill.

 

[Alan Johnson]

I think coffee has to be used to make caffeic acid but not quite sure.I don't think it could be made from caffeine in pep pills.

 

[Photo Engineer]

You guys are asking for a short course in both Organic Chemistry and Biochemistry in order to gain a full understanding of why things are or are not toxic. These subjects are far from simple. Here is a rough example though, in order of toxicity highest to lowest...

Catechol (1,2 Dihydroxy benzene), Hydroquinone (1, 4 Dihydroxy benzene), Caffeic Acid (3, 4 Dihydroxy Cinammic Acid). Caffeic acid is actually a composite of Cinnamic Acid and Catechol, but is virtually benign and has totally different physiological effects. All 3 are developers in rough order highest to lowest just as above. So, it probably has some relationship to the reduction potentials of these compounds.

BTW, Cinnamic acid is identical to Caffeic acid but without the two hydroxy groups. It is benign but also insipid to human taste buds, kind of like Caffeic acid. However, reduce Cinnamic Acid to Cinnamaldehyde and you have essence of pure Cinnamon flavor. When you open a bottle of Cinnamaldehyde, you feel like you want to drink it. Sadly it is an unpourable slush on an average day and only melts on very hot summer days. But, again, Organic and Biochemistry are arcane, interesting and mysterious subjects.

PE

 

[JBrunner]

You guys are asking for a short course in both Organic Chemistry and Biochemistry in order to gain a full understanding of why things are or are not toxic. These subjects are far from simple. Here is a rough example though, in order of toxicity highest to lowest...

Catechol (1,2 Dihydroxy benzene), Hydroquinone (1, 4 Dihydroxy benzene), Caffeic Acid (3, 4 Dihydroxy Cinammic Acid). Caffeic acid is actually a composite of Cinnamic Acid and Catechol, but is virtually benign and has totally different physiological effects. All 3 are developers in rough order highest to lowest just as above. So, it probably has some relationship to the reduction potentials of these compounds.

BTW, Cinnamic acid is identical to Caffeic acid but without the two hydroxy groups. It is benign but also insipid to human taste buds, kind of like Caffeic acid. However, reduce Cinnamic Acid to Cinnamaldehyde and you have essence of pure Cinnamon flavor. When you open a bottle of Cinnamaldehyde, you feel like you want to drink it. Sadly it is an unpourable slush on an average day and only melts on very hot summer days. But, again, Organic and Biochemistry are arcane, interesting and mysterious subjects.

PE

Exposure and exposure method are also a huge part of toxicity. Is water toxic? Yup, if you breath it. Is spinach toxic? Yes, if you eat a huge quantity. Toxicity is relative and dependent on other factors than the substance. Judgements regarding toxicity must include these factors or else nearly everything can be seen as toxic or benign.