Comparing Ilford 120 Films

[Coldkennels]

Delta is an epitaxial grain film, not flat/t-grain. They are very different.

I stand corrected! I could have sworn Delta was Ilford's TMax equivalent and they used similar technology. What exactly is "epitaxial grain" compared to T-grain, then? That's not a term I've heard before.

Most of my B&W work is Delta 100 and Rodinal. I tend to think one's scanning technique adds as many variables into the equation as anything else.

This does look lovely, but again... medium format. Rodinal in medium format is a lot more forgiving than Rodinal in 35mm.

 

[Muggins]

I stand corrected! I could have sworn Delta was Ilford's TMax equivalent and they used similar technology. What exactly is "epitaxial grain" compared to T-grain, then? That's not a term I've heard before.


This does look lovely, but again... medium format. Rodinal in medium format is a lot more forgiving than Rodinal in 35mm.

It certainly is!

 

[Freakscene]

I stand corrected! I could have sworn Delta was Ilford's TMax equivalent and they used similar technology. What exactly is "epitaxial grain" compared to T-grain, then? That's not a term I've heard before.

T-grain films have tabular, flat crystals that grow along their own edges and not on the main planes of the crystal growth. This makes them flat parallel to the film giving them more surface area and less scatter. It’s also why they need more fixing, because the grains fix from the edges in.

Epitaxy is a method of growing very well-ordered crystals. In Delta films these grow as trapezoids, not flat plates, along a plane. Some films use both flat grains and epitaxy, with epitaxial growth contributing to the high quality and fine grain of modern films. But Delta doesn’t use flat grains.

Also, monosize emulsion technology is important. This is a chemical approach that creates grain of a much more limited range of sizes. Acros, as an example, is a monosize traditional cubic grain film, and it has grain almost as fine as TMX.

Kodak’s simple explanation of t-grain is archived here:

Wayback Machine

And an edit: the Wikipedia page about tabular grain films is so wildly inaccurate I won't cite it.