[Leica] IMG: Another Comparison

[red735i at earthlink.net (Frank Filippone)]

Yes, IF it is an even shift, which the IR issue is not...... 

As explained technically, the IR is more strongly reflected by certain 
fabrics ( I read that as surfaces)....  However, your eye can
not see the IR, so the eye does not pick it up.  The sensor is sensitive to 
it, so it picks up the reflected IR light in amounts
that vary dependent on the surfaces involved.  So your eye and the sensor 
are seeing different amounts of reflected light, in
different parts of the image captured.

Now the WB..... this is an overall warping of the color of the image.  
Everything gets moved at the same time.

Would WB work?  Sure, if you have a monochromatic reflective surface with no 
background or foreground... sort of the shot of black
fabric on black fabric.  Then all the image would have the same amount of IR 
and it could be corrected....

But if you place a person against the same black cloth, lit the same way,. 
The person's face ( legs, arms, whatever) would reflect
the IR light differently than the cloth, but he corrections would be applied 
the same....  black cloth, (maybe ) blue face.

Is this clearer why it will not work?

Why does it kind of work with certain images?  Because the amount of IR 
present is pretty low and the reflectivity of the surfaces
is also low/  so you have less to correct, and the WB used is less intense, 
therefore it works, kinda.  Very image specific... 2
images takes seconds apart from slightly different positions will get 
different results.

BTW, what would work is corrections in PS using ( and I am absolutely NO 
expert ) selective color corrections.  Mark the cloth,
change the color.  Mark the face, change the color.  Very selective.....big 
PITA.

Frank Filippone
red735i@earthlink.net 
Tina

I though Photoshop could correct just about any color shift? I was 
trying with the Underwater filter and it seemed to help.


Walt