i really dont get it how anybody can be content with colorcasted images, does not matter if phase leica kodak sinar hasselblad or leaf stands on the tool.
but it seems so that 99% of the users dont care, cause they dont see the casts. for me they often are visible even in normal motifs,- probably because i have trained my eyes to see them.
if more shooters would realize them, since years would be out software solutions which work PRACTICAL ( means fast).
i say this because the leaf and phase solutions are very complicate, although at least they offer a solution. the rest not. except brumbaer tools for sinar, which was designed to offer here a fast workflow and not only a basic functionality to calm down complainants.
i came to this cast problem first time with my kodak 14n and with the kodak slr and searched a solution for this cameras. they used a kodak chip as leica ( and phase and hassy ) are doing now.
this kodak chips are traditional the worthiest in terms of color shifts.
for me the kodak slr simple wasnt usable ( and the dmr wouldnt be it either ) if i would not have figured out a workflow to remove them every time i wanted.
so here it is ( sorry i cant say the exact names of the ps tools cause i have a german version only, but i think it should be clear what i mean ):
1. you need a white plexi to make a white shot, just to capture in it the color shift , nothing more.
you can buy it from sinar in form of 10x10cm or a round 72mm filter,or from leaf.
or you have an old light-box and cut out a 10x10cm piece.
2. before or after EVERY shot you take an exposure with the same setting as you shoot later,
exposure should be two stops higher but use the same f.
3. you develop this white shot in the same way as the motif in the raw converter and import it to photoshop.
4. layer the white shot and make an overlay layer out of it.
5. convert the file to LAB without reducing the layers
6. set the tonal values of the luminance channel ( only) of the overlay layer to 128/128. no you see only the pure color shift in this layer without any vignetting.
7. invert this layer. theoretical now the color shift will be removed to 100%. in practice you have to play a little bit with the layer. increasing the contrast of the layer will remove the shift more, decreasing it less. same happens if you higher or lower the saturation of the layer.
( 7b. in long time exposures denoise the layer or blur it. otherwise you multiply the color noise. you can blur it with a good amount, cause the color shift has no sharp corners or details. )
8. after you are content with the result, merge the layers and go back to your RGB color-space.
this method works perfect and with a bit of routine even fast.