Digital BW, The Print

Great job Preston--Thanks!  The circular gradient really shows up the 
problems.  I too find Keith Cooper's image a very useful tool.

I'd also like to reintroduce the group to Tyler Boley's offset grad 
linearization test image, see Files|Image Processing|offsetgrad8.jpg.

Non-linearities show up as faint upper left to lower right diagonal 
bands.  The location(s) can be directly read off the scales.  Any non-
linearities show up best when viewing the print in good light.  Also 
faint bands can be better identified if the print is rotated and/or 
tipped back and forth (enhanced by our primative ability to sense b/w 
motion).

jr