[filmscanners] Re: Tips needed on difficult scan

["Dave King" <kingphoto@mindspring.com>]

----- Original Message -----
From: Julian Robinson <jrobinso@pcug.org.au>
To: <kingphoto@mindspring.com>
Sent: Monday, January 07, 2002 11:52 PM
Subject: [filmscanners] Re: Tips needed on difficult scan


Being endlessly interested in contrast taming, I just tried this but
obviously I am missing something because I can't get it to work.  I
certainly don't understand how it works, mostly because I don't know what
"screen" does :(  Is the technique assuming the dark or light image on top,
or doesn't it matter?

It does remind me though of the other semi-automatic way of improving high
contrast images which works quite well, although if overused gives some
strange effects on the light-dark transitions and at the edge of image.

Contrast masking...
- Image needs to be in 8-bit which is a shame.
- duplicate it into a second layer
- desaturate top layer and invert (make it a negative of itself)
- select OVERLAY as mode
- gaussian blur this top layer to 20-70pixels until you get the best effect
- reduce the effect if necessary by reducing transparency of top layer

Julian

I love this technique for contrasty chromes (never need it for negs with
Vuescan), but I question the need for the gaussian blur part.  The digital
"contrast mask" is an exact pixel for pixel overlay, and old school film
contrast masks were made "out of focus" to compensate for dimensional
instability between film and mask layers.... not an issue with digital.  So
another way to do this is no blur and much lower transparency on CRM layer.
20 to 40 percent is all you can do without a blur, but IMO looks better than
using blur.  The contrast reducing effect moves faster but with more
precision in final result.

Dave

----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe 
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or 
body