Magenta colors in vurescan with LS4000

[Mario Boller]

I love vuescan at most, but I have a problem. I am using vuescan 8.03.
In neutral color mode I had some color problems on dark pictures with
yellow lights - all dark parts became blue. So I decided to use manual
color correction instead, in the hope the scanner would do nothing to
destroy colors. All values in manual correction are at default (1 for
all colors and so on).

I use LS4000 batch mode with type "image", 48 bit RGB, 4 times scan
and long exposure pass.

Most of the pictures are OK. But on pictures with very bright parts
like a bright white sky or a white pigeon, I get a terrible magenta
color engraving all over the picture.

Has anybody an idea what settings to use to get fairly good results
for all pictures?

 

[Jeff Randall]

Mario: This workflow works for me on my LS-4000, your mileage may
vary.

Set media to Image. Set color balance to autolevels (this will force
the brightest areas to white). I also set the white point to somewhere
between 0.2 to 0.5. Remove any remaining color casts by tweaking the
individual RGB brightness values (actually RGB gammas) and adjusting
overall brightness with Brightness.

This is the only way I've found to control the strong blue cast with
Kodachromes on the LS-4000. I think Ed Hamrick's advice of using
manual color balance assumes the color cast is "linear" or constant,
however my experience indicates that on the LS-4000 it is not and
requires changing RGB gammas to remove.

Experiment.

Jeff Randall