Roman Kielich <[EMAIL PROTECTED]> wrote:
> All modern films have a multilayer construction, each R, G, B - sensitive
> layer consists of 2 or 3 layers of different speed (grain size). The
bigger
> the grain, the bigger the speed. If you underexpose a film, you record an
> image in more sensitive layer, which is grainier. That construction allows
> for a bigger exposure latitude.
And that's precisely my concern about underexposure. I've underexposed
enough
film to have seen the increase in grain. :)
> why do you need 28 mm lens at 2 m distance to measure/assess the
> grain?
Because it makes the target a predictable size.
> the image doesn't have to be sharp to determine grain size.
No, but remember it's not the *real* grain we're looking at here. It's the
result of aliasing.
> According to Fuji- diffuse rms granularity
Thanks for the figures! They'll come in very handy. Does anyone have
similar specs for other brands like Kodak, Ilford, and Konica? Please
email them to me.
The point of the exercise I want to do is not to accurately measure the
grain of a given film. The scanner isn't capable of that. The point is to
scan various types of film and see which ones have grain/dye structures
that generate the least aliasing. In other words, the ones which have the
least "grainy" look in the scanned result. It's a purely subjective
measure,
but I want to use standard targets for consistency in the images being
compared. I think I now have all the materials I need to come up with
a protocol.
If anyone with a Nikon scanner (LS30 or LS2000) would be prepared to
take a couple of photos on their favourite film for this purpose, please
email me. I would prefer to stay with Nikon scanners at the moment
for consistency and the fact that the Nikons appear to see more "grain"
that other scanner brands. For this exercise, the differences between
the LS30 and LS2000 should be negligible.
Rob
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