2 different dev times - meet in the middle?

cardiff_gareth

cardiff_gareth

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Quick one.

I bought a roll of Fomapan 400 to try out as well as a roll of Kentmere Pan 400 and shot them both on holiday.

Ideally I'd like to develop them together to save chemicals as I have a 2 film dev tank.

Using Ilfosol 3 with a mixture of 1+9 at 20°C the Fomapan is 8m50s and the Kentmere is 6m30s.

I'm wondering if I can A) develop both at the longer time of 8m50s and if I did that what would happen to the Kentmere film, or B) develop in the middle as there is 140 seconds difference, divide that in 2 so 7m40s so one is slightly under developed and the other slightly over.

Or is it a case of 'it is what it is' and I'll balls up 2 times so suck it up and prep 2 lots of dev, fixer and stop bath and do one at a time?

Annoyingly the ISO 100 Kentmere and Fomapan I bought have the same dev times, it's just the ISO 400 films that differ.
 
cardiff_gareth said:
Quick one.

I bought a roll of Fomapan 400 to try out as well as a roll of Kentmere Pan 400 and shot them both on holiday.

Ideally I'd like to develop them together to save chemicals as I have a 2 film dev tank.
Click to expand...

Shooting two films you're not familiar with for your holidays sounds risky. Developing the Foma in a developer that's not amongst the ones recommended by the manufacturer sounds extra risky. Developing that Foma for a shorter time than what you found on the Massive Dev Chart sounds kamikaze.

ILFORD Ilfosol-3 500 ml conc. - fotoimpex.com analogue photography

ILFORD ILFOSOL S is a general purpose liquid concentrate black and white film developer. Particularly suited to developing medium and slow speed films such as PAN F Plus, ...
www.fotoimpex.com www.fotoimpex.com

Fotoimpex sells a 500 bottle of Ilfosol-3 for 11.89 Euro. Supposing you're using a AP or Paterson tank you'll probably use max 400ml of solution for one 35mm roll. At 1+9, this means you'll need max 40ml of Ilfosol/film. Therefore supposing you'll develop just 35mm rolls with this bottle, and that you'll develop them one at a time, you're spending 99 cents of developer per roll. I'd go for that.

Is it really worth potentially compromising some irreplaceable holiday memories to save a few cents?
 
If you underdevelop the Fomapan, you will end up with negatives with reduced contrast. If you overdevelop the Kentmere, you will end up with negatives with increased contrast.
I would develop them separately and reduce the amount of developer in the tank - you only need enough developer to cover the one reel. If you don't already know how much this is you can measure it using an empty spiral. This way you will use very slightly more developer and have two well developed films.
 
I've been keeping Diafine in the cupboard for similar reasons to this (as well as other reasons). With Diafine, the developing time is the same for any B&W film, the temperature is unimportant, and it keeps forever. Theoretically, you could develop an ISO 50 film in the same can as an ISO800 one. It also allows you to have ghetto "auto ISO" on the same roll (as long as you stay within the film's push-pull latitude).

Downside is that it's not great for T grain films (TMAX, & Ilford Delta range) and also you can't control the contrast by over/under developing as the time is the same for all films.
 
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