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.



Unfringe filter
===============

Copyright 1997, Berthold Daum


This PhotoShop FilterFactory filter has been designed to remove
coloured fringes from scans as caused by poor scanner registration
or lousy scanner optics. In limits, it can also be used to remove
fringes resulting from bad camera optics.

Creative use of the filter would be to introduce coloured fringes
into an image at will.



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

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

For Mac users we have included the source code unfringe.asf.
The naming for the 6 sliders is:
RedX, RedY, GreenX, GreenY, BlueX, BlueY.

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

The unfringe filter allows to apply an offset to each colour component 
(Red, Green, Blue).
The scaling of the sliders is a bit strange due to FilterFactory limitation.

128 is the neutral position (Offset 0), and steps are counted in 1/8 of a pixel.

The unfringe filter should be used directly after scanning - especially before 
all sharpening operations! It is best to make a test first on a small selection 
containing some sharp edged structures. Then apply the filter to the whole image 
using the same slider values.

It is probably possible to use the same slider values for all images
scanned with the same resolution. However, scanner registration could 
change with temperature and over a longer period of time, so it might 
be good to double check from time to time.



