Where has Foma gone?

[pentaxuser]

I recall it was after doing some searching to see if there was much known about Fomapan 200's high-aspect-ratio grain structure & camera incompatibility in 120 - and that there was some reasonably well-sourced commentary to the effect that while the factory was highly aware of these and other issues, upgrading the materials to equivalent standards of sharpness/ speed/ overall quality control would raise their retail prices to the level of Ilford/ Kodak

What is/are the camera incompatibility in 120? What is a high aspect-ratio grain structure in layman terms?

All you're telling me is that your confirmation bias is blinding you. I can live with some of Fomapan's shortcomings, and their specific aesthetics can be a strong point for a particular kind of 'look' - but under no properly rigorous industry-standard measure (and we're not talking about the developer-tasting garden-shed-test-chart amateur-grade rubbish here) are they in any way equivalent or better to Kodak or Ilford etc in speed/grain/ sharpness - and Foma are honest about that.

Just a pity that you cannot recall the source of Foma's honesty about its film shortcomings. I presume that Foma did not express their shortcomings in such stark details and that there is an element, at least, of your interpretation of what it actually said wherever it said it?

Do most of the attempts by member here to conduct their tests and produce charts fall into what seems to be garden-shed-test charts amateur grade rubbish? Are there any sources for film tests that we can trust such as Greg Davis, Henning Serger etc?

Thanks

pentaxuser

- but there seem to be good reasons not to do so too (not financial - if it was purely financial, making epitaxy work would have happened) in particular from a perspective of dealing with problematic end users who cannot understand the basics of process control despite owning enough grey cards (and photographs thereof) to paper the walls of several rooms.

 

[Lachlan Young]

What is/are the camera incompatibility in 120? What is a high aspect-ratio grain structure in layman terms?

'High aspect ratio grain' = T-grains or other methods to produce flatter halide crystals (e.g. Delta gets to the same end by different means) - as opposed to '3D' crystals that have greater depth - they seem to be better terms to use because the structures are often more complex in shape than simply 'tabular' or 'cubic'. If T-grains (in particular) go round too tight a bend on too thin a support, it seems that crystals above a certain size may be prone to 'cracking', causing fog. From what I recall, Tri-X in 120 was coated on a 3.6mil triacetate base, Ilford uses 4.33mil triacetate in 120, Tmax 100 uses 4.7mil triacetate (unclear if 400TMY-II needs same base thickness - or if it and 400TX have both gone to the same base as Ilford (I think that Portra definitely is) - which would make sense from a supply perspective & possibly clarify why 100TMX in 120's price jumped more than the others) and Foma uses 4mil polyester (as far as known).

I presume that Foma did not express their shortcomings in such stark details

It's in their own data sheets that their materials have overall lower MTF performance (less apparently sharp - especially at low frequencies - which will give Foma materials a more 'vintage' look), worse granularity (hence lowering total information capacity) & require speed increasing PQ developers (Microphen type) to reach specified shadow speeds.

 

[pentaxuser]

'High aspect ratio grain' = T-grains or other methods to produce flatter halide crystals (e.g. Delta gets to the same end by different means) - as opposed to '3D' crystals that have greater depth - they seem to be better terms to use because the structures are often more complex in shape than simply 'tabular' or 'cubic'. If T-grains (in particular) go round too tight a bend on too thin a support, it seems that crystals above a certain size may be prone to 'cracking', causing fog. From what I recall, Tri-X in 120 was coated on a 3.6mil triacetate base, Ilford uses 4.33mil triacetate in 120, Tmax 100 uses 4.7mil triacetate (unclear if 400TMY-II needs same base thickness - or if it and 400TX have both gone to the same base as Ilford (I think that Portra definitely is) - which would make sense from a supply perspective & possibly clarify why 100TMX in 120's price jumped more than the others) and Foma uses 4mil polyester (as far as known).

So is it the fact that it is polyester as the base that makes it the problem for T -grains or the fact that it is 0.3mil less or a combination of both?

It's in their own data sheets that their materials have overall lower MTF performance (less apparently sharp - especially at low frequencies - which will give Foma materials a more 'vintage' look), worse granularity (hence lowering total information capacity) & require speed increasing PQ developers (Microphen type) to reach specified shadow speeds.

Does Foma say that to get to box speed you need certain kinds of developers or assume that users of its films will work out from Foma data sheets that you need to do this. If it does assume this then that certainly seems quite an assumption on its part and one not justified for most of its users

Does this apply to all its films or only certain speeds. Certainly Greg Davis' test on both Foma 400 and 200 suggests that full box speed was not reached in either but it was in Foma 100. In fact if anything Greg's curve for Foma 100 was slightly steeper and he said that it might have greater separation in the shadows than Tri-X So it would seem that not all Foma films suffers from whatever requires speed increasing PQ developers unless there any reason to suspect Greg's curves and his conclusions on box speed. Is there?

Thanks

pentaxuser

 

[radiant]

Nothing really scietific here.. but I exposed & developed Foma 100 & 400 identically (same tank) and Foma 400 looks really identical in terms of speed compared to 100 - and performs much worse:

https://www.photrio.com/forum/attachments/na%CC%88ytto%CC%88kuva-2022-2-26-kello-21-11-44_1024-jpg.299342/