Develop film with Potatoes

A potato based film developer mixed up during the first UK lockdown out of desperation for creativity and coffee.

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Coffee as a base for a film developer is expensive, has to be shipped in from the coffee producing zones and is not available in locally grown form.. I’d rather drink the stuff, so I started thinking of alternatives. As for many people during lockdown, days blended together and some stuff was in short supply. I wanted to develop film and have my cup of coffee damn it! The actual research was lost to time but over the course of a week, a mix of common household chemicals was derived.

The ingredients and method are easy to follow.


500ml water + 300 grams of potato
8 teaspoons of washing soda and 
2 teaspoons of vitamin C
Add water to make up 1000ml

The procedure is;

Blend 300 grams of potatoes
Add water (500lml) & blend said chunks until you have a smooth soupy mix.
Filter the liquid (I made a 3D printed funnel with a washing up sponge as a course filter).
Mix in washing soda
Mix in vitamin C
Add water to 1000ml @ 20 degrees C

Add to film tank, shake for 30 seconds and then stand develop for 2 hours on 100 ISO film. Stop with water + fix + wash as usual.

Stand developing is basically pouring in the developer and then leaving it to sit for a long time while you enjoy a lovely cup of coffee.

Maybe for future mixes, I'll filter the potato sludge with a Cafetière. it doesn't need to be perfect, just free of big lumps and most of the fine sludge.

The resulting scanned negative is included in the photos for this project. This was a 4" x 5" negative from my MPP Large format camera.

  • Salt fix?

    m.kelsall10/06/2023 at 12:11 0 comments

    If you're using a digital workflow for negatives, then the lifetime of the negative could not be an issue for you? Have heard that using a really strong sea salt solution can fix, but it's really really slow.

  • Developer strength

    m.kelsall10/06/2023 at 12:03 0 comments

    The reason why I use stand developing for all developers, is on account of me having arthritis and muscles that lock up with use. So you could say the formula was arrived at for my needs.

    Some of you need to do testing with different amounts of potato. Would be great to hear your feedback and have your help.

  • Removal of silver..

    m.kelsall10/06/2023 at 12:00 1 comment

    As noted in the Hacked news feed, there are still problems with silver ions floating around. They may be able to be extracted from the solutions. I know it can be done with fixer.

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rnjacobs wrote 10/05/2023 at 19:03 point

What's the chemistry going on here?

  Are you sure? yes | no

m.kelsall wrote 10/06/2023 at 11:46 point

I hope that someone will help with that, it was a really difficult period where something called retrograde amnesia was a problem on account of having a maniac for a neighbour. Found the recipe in a photographic log book on mine from that period.

  Are you sure? yes | no

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