Yerba Mate Developer

[laingsoft]

Looking through my collection, I accidentally opened my Canon TX that happened to have a roll of Hp5 in it that I had forgotten about. I quickly closed the camera and shot the last few frames, then rewound it and thought I'd give an idea I've had floating around in my head a go with this film.

Yerba Mate is a tea that contains a whole smattering of potential compounds for developing. Polyphenols and a handful of compounds that should work as developing agents, including Dicaffeolquinic Acids, Rutin, Quercetin and Kaempferol, as well as vitamin C and more caffeic acid than present in coffee and tea.

24 grams of Yerba Mate leaves were added to a plastic beaker and 300ml of boiling filtered water was added and allowed to steep with constant stirring on a stir plate for 5 minutes.

The Yerba Mate tea was then filtered through paper towels, followed by a second filtration through cotton balls. Cold water was added to make 1L. 20g of vitamin C powder was added with constant stirring. Then 24 g of sodium carbonate. The mixture was allowed to stir until completely dissolved. The pH was checked and read to be approximately 9.4.
A clip test was performed, and greying of the strips occurred after approximately 7 minutes. I decided to add more alkali, so Carbonate was added until saturated (I couldn't add more because it stopped dissolving and it was making a mess) The final pH of the developer was ~10.24

A clip test was then performed, Strips of film leader were cut and dipped into the solution for 1 minute, 2 minutes, 4 minutes, and 10 minutes. The 2 minute strip showed greying, so multiplying this by 5, a 10 minute development time was chosen.

The film was then developed for 10 minutes at 38C, fixed, washed and stabilized normally.

Frames came out kind of OK, however they were heavily fogged. The exposures taken before I opened the camera were fogged slightly more than the exposures taken after, however the final images on the roll were still heavily fogged.

Potential areas of the recipe to change:
Using Sodium Hydroxide rather than carbonate,
Reducing the pH of the solution
adding Benzotriazole, Potassium Bromide, Potassium Iodide to retrain development and control fog.

Questions for APUG:
What would be the best way to kill the fog? Kill the Alkalai? Don't add Vitamin C?

I have a bulk roll of Arista 100 that I'd like to use up, so I can design a series of experiments to take this through, but I'm not sure what the best way to kill the fog is going to be. I think yerba mate might be something worth looking into though.

Scans of the frames I developed tonight will be posted later, as they are still drying.

 

[Rudeofus]

You have to have the Ascorbic Acid in this developer to obtain significant density, although the 20 grams sound a bit excessive. With the first matching amount of Sodium Carbonate you probably neutralized the acidic Ascorbic Acid and raised pH to 9.4. If you add more and more Sodium Carbonate after that, the pH will saturate somewhere above 10. I recommend you do not got much beyond pH 10, as it takes progressively higher amounts of Sodium Carbonate to reach minute (and likely ineffective) raises in pH. If you really need higher pH, try to find Trisodium Phosphate, this easily raises pH up to 12.

About the fog: I would start with Potassium Bromide, since this is easier to dose. The effect of a given amount added strongly depends on the developing agents you use - and we simply don't know this in your case. See what happens with increments of 0.1 g/l. You can try this with very short unexposed test clips, so no reason to risk whole rolls of film. Don't be too afraid of a base density of 0.5, since this developer will lose speed anyway, and killing all fog will likely reduce speed even more.

 

[koraks]

About the fog: I would start with Potassium Bromide

Yes, it add sulfite. It may inhibit staining in case this contributes to the fog, which I can very well imagine.

Of course trying to optimize this is kind of challenging due to the lack of control and even precise knowledge of the constituents of the mate solution/infusion. Btw, I have a feeling that the activity if this developer is mostly due to the added vitamin C with the mate contributing only marginally...

 

[Alan Johnson]

You have to get the pH low enough that the ascorbate does not do all the developing and develop for a long time to allow the big molecules in tea to do some work.
This can be checked by leaving out the tea in a separate test.
It's experimental, as in Keatings Green Tea Phenol Developer:
https://www.diyphotography.net/how-...eloper-from-peppermint-and-green-tea-extract/

 

[laingsoft]

You have to get the pH low enough that the ascorbate does not do all the developing and develop for a long time to allow the big molecules in tea to do some work.
This can be checked by leaving out the tea in a separate test.
It's experimental, as in Keatings Green Tea Phenol Developer:
https://www.diyphotography.net/how-...eloper-from-peppermint-and-green-tea-extract/

The first pka of vitamin c is around 4.2 and the second around 11.2, which is a pretty high range. Like the poster's above have said, with a 45+ minute developing time it's unlikely that his polyphenols are really doing anything, and a majority of the action is probably coming from the vitamin c. A true test of this is going to be developing the film without any added vitamin c. I think that may be the next route I'll take.

 

[Alan Johnson]

https://www.photrio.com/forum/threads/developer-from-green-tea.88196/
I started by trying to extract the active compounds from tea.

 

[Donald Qualls]

Your fog might actually be stain (akin to what Caffenol produces when used without ascorbate, or the stain from pyogallol or pyrocatechin). One way to check is to use C-41 bleach and fixer or blix (or Farmer's Reducer) to bleach away the silver image in the negatives and scan them with a big contrast boost to see if there's a faint stain image present. If so, solutions might include adding additional antioxidant (sulfite), reducing pH into the mid-9s, or just living with the stain. Stain, if present, often causes negatives to print better than they scan (the stain reads as density to enlarging paper, more than it does to a scanner). If you have the software to do so, you could also compare scans in blue light (scan in color, then perform RGB separation in software) to those done with default settings to check for stain.

 

[laingsoft]

Your fog might actually be stain (akin to what Caffenol produces when used without ascorbate, or the stain from pyogallol or pyrocatechin). One way to check is to use C-41 bleach and fixer or blix (or Farmer's Reducer) to bleach away the silver image in the negatives and scan them with a big contrast boost to see if there's a faint stain image present. If so, solutions might include adding additional antioxidant (sulfite), reducing pH into the mid-9s, or just living with the stain. Stain, if present, often causes negatives to print better than they scan (the stain reads as density to enlarging paper, more than it does to a scanner). If you have the software to do so, you could also compare scans in blue light (scan in color, then perform RGB separation in software) to those done with default settings to check for stain.

I'll clip away a negative and give it a shot. I do have a c41 blix that I can use. I'm assuming that it would also work if I was to blix a section of the leader?

 

[Donald Qualls]

@laingsoft The leader won't tell you if there's a stain image. If you can scan in color, I'd start with that; it's non-destructive. Stain is usually yellow/brown => minus blue, so the blue channel of a color scan will show higher density and contrast if there's a stain image present (though if the stain image is faint, it may not be obvious).