Epson 2450 - Grayscale blocking of highlights

[David Meriwether]

In scanning a 21 Step grayscale wedge, I discovered that my highlights are washed out from step 15 on (247+). Shadows are even to step 6 then take a big jump. Midpoint, step 11, is 180 instead of 128. I am working in PS7 under MacOSX.2 with Generic Gray Profile. Silverfast Ai is not reading steps evenly at all. No auto choices for "Standard, Landscape, etc." have significant change. Do I need a custom profile? I work only in b/w and so did not think that It8 would be appropriate. Suggestions?

[theo]

I had/have a similar problem.

The way it seems to work out for me is the following:

I choose the Profile: Other/Other/Monochrom
For most negatives I set the exposure to 0.0
One important parameter seemed to be the gamma setting
in options. I use now 1.3.

This gave me a linear grayscale response (K vs. Density)

I will post the results of my investigation in the Web on the following page:
http://www.tkupfer.de/imaging/scan_negative.htm