Guinneol: developing a roll with Guinness beer

I always try out new development systems. The more experimental the better — it is the best way to keep the workshops fresh and to really understand what happens inside the tank.

This time: Guinness beer.

The recipe I found was called “Guinnes” and the translation was, let’s say, creative — it talked about “detergent” when it clearly meant soda carbonate. It is not the first time a bad translation complicates a process that should be simple. But with a bit of chemical judgement, it sorts itself out.

The Guinneol recipe

Guinneol is, in essence, a Caffenol where the coffee is replaced by stout. The chemical base is the same: an organic developing agent (in this case Guinness’s polyphenols), an alkaline accelerator (soda carbonate) and vitamin C to boost activity and reduce fog.

For a standard 35mm tank:

• 440 ml of Guinness — the home can came to exactly 44 cl, which is the amount I used
• 50 g of soda carbonate — nothing to do with caustic soda; important not to confuse them
• 12 g of vitamin C — pure ascorbic acid, from a pharmacy or herbalist

The process

Developer preparation

Mix the beer, the soda carbonate and the vitamin C in a one-litre container. Stir well — very well — until the carbonate has no lumps. I use an old hand blender for this.

Heat the mixture to 30 °C. The microwave does it in seconds, but watch out: it is easy to overshoot. Check the temperature with a lab thermometer.

Loading the roll

In the dark, put the roll onto the spiral and the spiral into the tank. I used a Lomography Lady Grey 400, a film with good latitude that holds up well with experimental processes.

Development

1. Fill the tank with tap water for 1 minute (pre-soak)
2. Drain and fill with Guinneol at 30 °C
3. Continuous agitation for the first minute
4. From minute 1 to 15: 10 seconds of agitation every minute
5. Total development time: 15 minutes at 30 °C

Finishing

• Drain the tank and wash by agitation 5 times (about 2 minutes)
• Stop bath — optional, I did not use one
• Commercial fixer for 5 minutes
• Final wash: 6 minutes of agitation
• Antistatic for 1 minute
• Hang the film and let it dry

The results

The resulting negative has acceptable density and grain slightly more pronounced than usual — similar to the Caffenol but with a slightly different tone. It is not a precision developer: it is an experimentation developer.

If you scan the roll, do it in colour with automatic adjustments. A scanner reads negatives of this type better in colour mode than in B&W, and the results can surprise you — sometimes pleasantly.

Enlarger prints are possible but fiddly: the uneven density of the negative means a lot of test strips. If what you want is a flawless print, this is not your process. If what you want is to experiment and see how far you get, go ahead.

Guinneol is one of the processes we work on in the Experimental development workshop. If you want to try it with guidance and all the materials to hand, write to us.