By the numbersÅ ?


Christine Holzmann <tekila@...>
 

With the advent and popularity of digital cameras in newspaper
photojournalism a new beast has really reared its head.
It seems that unlike film that absorbs light consistently across the
spectrum (at least in theory) the digital CCDs on some digital cameras
(specifically the Nikon D1) the absorption seems to inconsistent (i.e. skin
tones are absorbing more magenta than say wood).

I have jumped through some major hoops with the curves and a mixture of
plate blending in both RGB and CMYK with sometimes great results and
sometimes a horrific outcome.

Trying not to over explain but often time I have, say a jacket, with an
appropriate CMYK value and faces with way too much magenta. Short of
selecting each object with the wrong value is there another way, as I try to
use the magic wand as little as possible?

Thanks,
Joey Benton
I experience the exact same problem...on one of the digital cameras we use, skin tones seem to take on an excessive amount of cyan......it is very difficult to correct this without ruining the rest of the image, so I have to correct the different objects in the photo selectively.
Another digital camera makes the skin tones take on far too much yellow.
As you stated, these color casts are not consistent across the image, so correcting the image "universally" does not correct the skin tone.

Crissi
____________________________________
--
DIGITAL/GRAPHIC ARTIST
http://www.crissi.com

DESIGN EDITOR @ THE CITIZEN NEWS
http://www.thecitizennews.com


Chris Murphy <lists@...>
 

Short of
selecting each object with the wrong value is there another way, as I try to
use the magic wand as little as possible?
You can use selective color, or replace color to fix these areas.
Alternatively, the camera can be profiled. The resulting profile for the
digital camera isn't just based on curves, but is actually a table. This
table is capable of allowing conversions from cameraRGB to some other
space (either Adobe RGB or your preferred CMYK space) with color-in-color
moves similar to what selective color uses. That is magenta would be
reduced in skin tones and increased in wood (or whatever the issue is
with your specific digital camera).

The results I've had with Kodak Input Profile Builder are quite good, and
I think Andrew has had very good results with Gretag Macbeth's solution
for making digital camera profiles. While you can use a regular Color
Checker for making a good profile, I've seen anywhere from 5% to 30%
improvements (camera dependent) using the new Color Checker DC which was
specifically designed for profiling digital cameras.

Now what this is going to do is balance the image and get it as close to
the original scene as possible. It's not going to fix bad exposures, and
won't do color correction, sharpening or image enhancement. It'll just
significantly reduce the amount of "hassle color correction" that you use
to solve weird camera behavior problems mentioned as examples in two
previous posts on this subject.

I understand Pictographics has a new product called inCamera
Professional. I haven't had a chance to use it yet. Praxisoft also has a
digital camera product as well. Andrew?


Chris Murphy