Beakman (beakman@netcom.com)
Sat, 22 May 1999 17:21:47 -0700 (PDT)
> Hi Adam,
>
> I thought we went through this in one of our personal emails, but maybe we
> didn't.
>
> rgb corresponds to transmittance, transmittance = rgb/255. Opacity =
> 1/transmittance, and density = log (opacity).
>
> But if you check the calibration scale of your imagesetter output, you will
> find that it is already well calibrated to the theorectical value. That means
> that you don't really have much to calibrate as far as density is concerned.
> You only need to calibrate the print process to match the rgb value (if like
> you said, you want to print by numbers), but it is also nice to match your
> monitor so that you can estimate the final look.
Not necessarily. I've worked with imagesetters for making digital negs --
actually doing all the calibrations, pushing the buttons and everything
myself -- and I can tell you that imagesetters are calibrated for PERCENTAGE
DOT but NOT for density. The density ranges all over the place, and as
the imagesetter runs, and the lasers heat up, it changes. The change in
density will not effect the percentage dot values (as used in offset
printing) hence it is of no concern to printers. HOWEVER, the density IS
important for alt-photo work because the negs print as a hybrid.
best regards,
David Fokos
This archive was generated by hypermail 2.0b3 on Thu Oct 28 1999 - 21:39:35