Re: [APML] DMax, was New Epson Scanner

["westergren" <westergren@netzero.net>]

Jerry or group,

How important is DMax when scanning film?  I think this is a situation where
"More is Better".  But we are only talking about after the film is exposed
and processed.  How does the film latitude factor in the overall "picture"?
It seems to me that the reduced DMax capability of negative film is offset
by it's greater latitude (and not burning bright objects out).

Don

> I don't really know what the maximum possible density is.
>
> Color negative films may have an optical density range around 2.8 and most
> slide films have an optical density range from about 3.2 to 3.6. Kodak
> claims its Kodachrome slide film can reach an optical density of 3.7.
>
> I haven't heard of anything more dense than this for everyday use, but
> there may be some highly specialized films for non-photographic
> applications that do, like lithographic films.
>
> I've never heard of a normal film having a D-max of 5 like Dale mentioned.
>
>  From my personal experience, I've scanned normal subject E6 films with
> very dark shadow detail on my LS2000, which only has a D-max rating of
3.6,
> and I've never had any trouble pulling detail out.
>
> The number given for the D-max is not the whole story, it depends on other
> factors also, such as the quality and the amount of noise in the
electronics.
>
> There is a whole book on scanner evaluation written by THE expert on this
> subject, Desktop Scanners: Image Quality Evaluation by Robert Gann, and he
> basically says don't pay any attention to the numbers at all, they are
> basically advertising hype and are measured differently by each
> manufacturer and none are really comparable.
>
> Jerry


_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo