Radial gradient filter
======================

Copyright 1997, Berthold Daum


This PhotoShop FilterFactory filter has been designed to 
correct the typical vignetting caused by wide angle lenses.
It will only correct the brightness fall-off caused by law of physics,
not brightness fall off caused by poor lens construction or inappropriate
filters or lens shades.

Creative use of the filter would be to introduce vignettes at will.


Installation
------------

PC users can copy radgrad.8bf into the Photoshop plugin folder.

For Mac users we have included the source code radgrad.asf.
The naming for the 3 sliders is:
Focal length, Effect, Overall brightness

How to use
----------

The radgrad filter should be applied to the full negative size. After scanning
crop only black film rebate before applying radgrad.

For the focal length select the focal length of the lens used for exposure
based on 35 mm negative format. Sorry, medium and large format users have to
do some calculations.

The adjust Effect and Overall brightness for best results: 128 is neutral.





