How much extra time for D-23 with benzotriazole?

Don Heisz said:

Looks good - hard to imagine it could look better, actually. Great job!

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Given the film went out of production seventy years ago, I have no complaints. Especially since I needed nothing that wasn't already in the house to mix the developer. First time doing DBI as well -- certainly easier with ortho film under red safelight (which can be pretty bright) vs. panchro under that incredibly dim amber-green OA filter.

Okay, I used this same half-liter of developer to process two rolls of Rerapan 100 (one after the other on the same reel, same method I use for 120) -- and found out what's meant by "loss of film speed" from benzotriazole. The highlights were fine, and a couple frames that had been slightly overexposed seemed okay, but the shadows were extremely thin in the normally exposed frames.

Won't do that again; it worked out well for 70 year old film in controlling decades of age fog, but for in-date film, it cuts at least one, perhaps two stops off the true film speed.

Donald Qualls said:

Okay, I used this same half-liter of developer to process two rolls of Rerapan 100 (one after the other on the same reel, same method I use for 120) -- and found out what's meant by "loss of film speed" from benzotriazole. The highlights were fine, and a couple frames that had been slightly overexposed seemed okay, but the shadows were extremely thin in the normally exposed frames.

Won't do that again; it worked out well for 70 year old film in controlling decades of age fog, but for in-date film, it cuts at least one, perhaps two stops off the true film speed.

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Are you reasonably sure that the activity of the developer had not declined following its previous use? I mention this because of the recent thread about D76 not being as robust as I would have expected for multiple rolls.

john_s said:

Are you reasonably sure that the activity of the developer had not declined following its previous use? I mention this because of the recent thread about D76 not being as robust as I would have expected for multiple rolls.

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The developer was used for the single (127 size) roll of Verichrome, then stored at room temperature in a tightly closed PET bottle with very small airspace for exactly a week.

Any film developer in the D-76/D-23 range mixed as stock solution ought to still be good after this short storage time. Given factory 127 film is only about 230 square centimeters (~ 35.7 square inches => less than half a 120 roll) and normal seasoning for D-23 intended for replenishment is to process three 135-36 or 120 rolls in a liter of stock without replenishment, exhaustion shouldn't be an issue. The only factor I can see is the benzotriazole.