Re: Data for choosing film for stereo

[rlrylander@xxxxxxx]

Joel Alpers wrote:

> Tom Deering wrote:
> >
> > >1. The new Provia (RDPIII) has even lower grain than Velvia.
> > >However, the resolving power is unchanged from the current
> > >version of Provia (RDPII), which has somewhat less resolving
> > >power than does Velvia.
> >
> > Well, how the heck can that be?  Shouldn't there be a correlation between
> > grain size and resolution?
> >
>
> You'd think so, but it isn't as tightly related as it might
> seem. One of the Ansel Adams' books (The Negative, I think) has
> very large enlargements of a negative, one with larger grain
> that shows better resolution than the fine-grained one. Depends
> on developer, too, as some developers "eat away" at the grain,
> producing finer grain but lower resolution.
>
> Joel.

Some "enhanced saturation" slide films work by producing by-products during
development that inhibit the formation of complementary colors in the vicinity
of a dominant color.  This also has the effect of increasing "micro contrast",
a form of chemical "unsharp masking".  Edge acutance (related to resolution)
isn't always directly coupled to grain size - there's some eye of newt and
powdered bat wing mixed into the broth..

Rich.