Why can't Acros reciprocity failure be matched?

Vetus · Monday at 3:05 AM

Why can't Ilford, Kodak or Foma match Fujifilm Acros 100 reciprocity?

koraks · Monday at 3:07 AM

The R&D investment would not be recoverable in today's market. Note that Kodak and Harman are really not that far off with their TMAX and Delta films.

Prest_400 · Monday at 8:59 AM

It would be interesting to know what exactly defines reciprocity and what did Fuji do as to have the best across their range (Fujichromes are outstanding as well), which I guess of course is a very complex parameter given film engineering.

I always like to refer to PE's knowledge, from an old thread discussing Acros:

Photo Engineer said:
Reciprocity, raw stock keeping and latent image keeping are all controlled by a family of preservatives including heavy metal complexes and organic chemicals. Each company has a proprietary mix of these. Kodak uses Osmium and Iridium in emulsions at levels of a few milligrams / mole of silver. That is a very tiny amount. They also use phenyl mercapto tetrazole and tetra aza indene. There is some information in the various textbooks on this.

Method of preparation of the raw metal salt and the addition method are both critical in getting them to work.

PE

On a more speculative note, Acros II has this "Made in UK" which may or may not point to Harman; but it is also unknown to what extent do/if they manufacture the film. Might just be finishing-confectioning, coating also, or also everything from emulsion? No one knows.
It would be interesting to ask Harman But if they are manufacturing the film from emulsion to finished rolls then they may very well have the capability.

retina_restoration · Monday at 9:28 AM

Vetus said:
Why can't Ilford, Kodak or Foma match Fujifilm Acros 100 reciprocity?

Tmax100 has excellent reciprocity that matches Acros exactly: 5 seconds becomes 6, and 10 seconds becomes 13. The two are identical until you get up to 30 seconds or more, at which point Acros has only slightly better performance.
The mythology of Acros has people believing that it doesn’t require any reciprocity compensation at any exposure, and that’s simply not true when you get to 10 seconds or longer.

Lachlan Young · Monday at 9:17 PM

Prest_400 said:
It would be interesting to know what exactly defines reciprocity and what did Fuji do as to have the best across their range (Fujichromes are outstanding as well), which I guess of course is a very complex parameter given film engineering.

I always like to refer to PE's knowledge, from an old thread discussing Acros:

On a more speculative note, Acros II has this "Made in UK" which may or may not point to Harman; but it is also unknown to what extent do/if they manufacture the film. Might just be finishing-confectioning, coating also, or also everything from emulsion? No one knows.
It would be interesting to ask Harman But if they are manufacturing the film from emulsion to finished rolls then they may very well have the capability.

There's a not-nil chance that Acros II starts as a very close relative of Delta 100 with a few changes to sensitisers and components (e.g. reciprocity altering addenda) used in the emulsion finishing step. Unlike Kodak, Ilford and Fuji have both heavily commercialised the use of epitaxial crystal growth techniques for their high-aspect ratio emulsions in camera film products (as opposed to X-ray and other industrial film emulsions) and I would not be enormously surprised if a degree of technology sharing had not gone on over the decades (Ilford has by all accounts made quite a few B&W products for Fuji over the years). Ilford also has a very capable on-site organic synthesis team (otherwise XP2, never mind Phoenix, would not be possible).

Why can't Acros reciprocity failure be matched?

Vetus

koraks

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Prest_400

retina_restoration

Lachlan Young

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