Barry Thornton’s Higher Definition Two Bath

Barry Thornton’s Higher Definition Two Bath

Bath A
Metol 6.5g*
Sodium Sulphite 80g**
Water to 1 litre

Bath B
Sodium Metaborate 12g
Water to 1 litre

If you can not buy Sodium Metaborate the great John Finch has made a video showing how to make your own using Borax and Sodium Hydroxide.

NOTE: Please use gloves and make in a ventilated area for safety.

Using a Two Bath developer

All two bath developers are used in a similar way:

• Do not pre-wet the film!
• Pour in Bath A and rap the tank to dislodge any bubbles sticking to the film.
• Agitate gently for the first 30 seconds to one minute to completely soak the emulsion.
• Agitate for 10 seconds each minute.

After bath A, pour off the liquid and save it for future films.

Note: Do not rinse or stop the film between baths.

• Now, pour in bath B. Agitate for just 5 seconds and rap the tank to dislodge air that might stick to the emulsion.

• Agitate for 5 seconds every minute. Then pour bath B out and save it too. Bath B can be re-used also.

Jobo rotary developing machine use.

It is a given to reduce times by 15% but I will also do standard times to test results. After my testing I will enter the times that I will use.

• Stop and fix as usual.

Thornton’s two bath works very well at around 4.5 mins in A and 4.5 mins in B.

ISO 100 4min for A & B and ISO 400 5mins for A & B

I use a Jobo processor sometimes so the time will be reduced by 15% to account for the constant agitation.

Develops approx. 10 to 16 x 35mm or 120 films per batch.

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