filmscanners: Measuring scanner & film OD range

[Mike Duncan <mgduncan@esper.com>]

>> Austin writes:
>>
>> > Have you measured your transparencies to see
>> > exactly what you are achieving for density
>> > ratio numbers?
>>
>> No.  How would I measure it?  Don't I need fancy equipment for that?
>
>Pretty simply actually.  Take a particular type of film you are using.
>Unroll a part of it and expose it to full light.  Then have it developed,
>and have the film density read.  The exposed part will be one end of the
>scale, and the unexposed part the other.  If you want, put the clips in an
>envelope and send them to me and I'll measure them for you.  You can to it
>at the beginning of a roll, simply by pulling out N frames...then rolling
>them back in, and advancing the camera N+ frames, so you have some exposed
>and unexposed section.

That will only give you the end points.  If you have a slide copy
attachment (macro lens and film holder), you can dupe a grayscale slide
like the Stouffer.
Or photograph a gray or white card and vary the exposure in half stops.

When you scan this gray test film, turn  off scanner auto exposure.

Mike Duncan