Digital BW, The Print

Frank,

>Can it help an image, that is suffering 
>from 'posterization/solarization' appearances, if the 8 bit image is 
>converted at the end of the manipulation process to 16 for the curve 
>application and printing. ...

I have found that some curves produce smoother transitions if the 8 bit
files are converted to 16 bit RGB just before the curve is applied.  After
the curve is applied, it makes no difference if the image is converted back
to 8 bit per channel.  

There is something in the way the curves interact with the image file that
can cause stair-stepping in 8 bit mode.  This happens where the main color
curve at the point has a very low slope.  So, it appears to be the curve,
not the image file, that is affected by being limited to 256 steps.  I see
this in making the curves in that sometimes there are insufficient steps to
hit the target density right on.  A one unit (of 256) move will overshoot
the target density on the test strip.  This, I take it, is evidence of stair
stepping in the curve. (The curves give me only 256 steps even if the file
is in 16 bit mode, but in its application, the 16 bit depth seems to be
there.)

So, it's certainly worth trying a conversion to 16 bit before applying the
curve.  It may not be the source of your problem, but it's easy enough to
give it a try.

Paul
www.PaulRoark.com 

For UT2 information, curves, and settings see:
http://home1.gte.net/res09aij/