Digital BW, The Print

Jeff...

When measuring paper, you are measuring reflection.  When measuring film,
you are measuring transmission.  I believe the discussion at hand was about
measuring paper, so if you substitute "reflect..." for "transmitt..." in
what you wrote below, I believe it'll fit the discussion.

Regards,

Austin

>     This might help.
>  optical density (OD): For a given wavelength, an expression of the
> transmittance of an optical element. Note 1: Optical density is
> expressed by log10(1/T ) where T is transmittance. (188) Note 2: The
> higher the optical density, the lower the transmittance. Note 3:
> Optical density times 10 is equal to transmission loss expressed in
> decibels, e.g. , an optical density of 0.3 corresponds to a
> transmission loss of 3 dB. Def of optical density.
>
> Jeff