Plus X 7231 and 7276

Scott Pickering · February 19, 2015

I know one is a reversal and the other a negative film. Is it possible to expose and develop 7276 as a neg (skipping the reversal process)? I know the ASA is 50 on 7276 and 80 on 7231. I just thought they'd be cut from the same stock, so you could process as you'd want to.

Dirk DeJonghe · February 19, 2015

They are not the same stock. You can process 7276 as negative with some loss of speed, but you don't get the extended latitude of a real negative. Unfortunately 7231 is no longer manufactured.

Josh Gladstone · February 19, 2015

As far as I'm aware, all b/w stocks are able to be processed as negative or reversal.

Aapo Lettinen · February 19, 2015

As far as I'm aware, all b/w stocks are able to be processed as negative or reversal.

some stocks, for example Foma, have a silver rem jet layer which needs to be bleached to be able to see the image. Almost all the other stocks can be processed to negative if desired

Simon Wyss · February 19, 2015

As you say, Aapo, the subbing needs to be bleached and dissolved out of the film (through the image gelatine). It’s not a rem(oval)-jet back layer. Let’s please stay clear about things.

Fomapan R 100 is the last of its kind with a thin silver interlayer. The second last was Agfa Scala that had a manganese oxide subbing. More films have an anti-halo undercoat but these get discoloured during development: Gigabitfilm 40, some sound recording and duplicating stocks. Orwo PF 2 plus is a black-and-white positive print film with an anti-halo subbing. It is intended for printing from heavy (dense) negatives.

Josh Gladstone · February 19, 2015

Very interesting.

Freya Black · February 19, 2015

As far as I'm aware, all b/w stocks are able to be processed as negative or reversal.

It's true of the Kodak stocks but as Dirk suggests you lose a bit of speed in the process so you have to be aware of that when you shoot if you are developing as neg.

Freya

Freya Black · February 19, 2015

They are not the same stock. You can process 7276 as negative with some loss of speed, but you don't get the extended latitude of a real negative. Unfortunately 7231 is no longer manufactured.

7276 is also not manufactured any more sadly. The two versions of Plus-X were very similar apparently but there was a big change in chemistry and I understood they made some minor changes to the stock too. It's hard to remember now as this stuff has become historical sadly.

If you process them as neg the ASA will be different again so neither 50 or 80 but something slower.

Freya

Dennis Couzin · February 19, 2015

They are not the same stock. You can process 7276 as negative with some loss of speed, but you don't get the extended latitude of a real negative. Unfortunately 7231 is no longer manufactured.

Dirk, if you have a characteristic curve for 7276 (or 7265) developed in D96 to gamma 0.65 to 0.70, I'd be very interested to see it.

Scott Pickering · February 20, 2015

Thanks guys. I bought some of this stock recently. Just a few rolls, but he says he has more. I think I might leave the reversal film to regular usage instead of going neg with it.

Dirk DeJonghe · February 20, 2015

Dennis, I don't have any unexposed 7276. We process some from time to time for customers. Would gladly do the sensitogram if I get some stock.

Martin Baumgarten · March 16, 2015

There are still some supplies of PXR 7276 and the later 7265 out there. Both can be processed as a B&W Negative using a good continous tone developer such as D-76, Microdol, and many others. Tonal range seems quite fine from my experiments over the past few decades, and used and processed as a negative stock, it will be more forgiving of exposure errors (on the over-exposure end of course). Even so, a nice clean rich B&W Reversal image projected is still awesome! I'm so glad we still have TRI-X, despite the higher pricing now.