Probably I only do not understand fully the new color calibration module in combination with white balance, but applying the new workflow I am getting almost all of images having a slightly greenisch tint.
In addition I do not get the same color temperature shown in the color calibration module as in using the plain “white balance” module, both times using the “out of camera” setting.
To give an example: I am having an image where the “plain white balance” module is showing a color temperature of 4770K when choosing “wb from camera”, switching to “camera reference” and activating the color calibration module with the setting “wb from camera” I am getting CCT: 3844K (daylight)
Shouldn’t this go to a similar value as before, e.g. round about 4770K?
I think this is what’s happening, hopefully someone who knows more about color science than I do can double check whether or not is correct - I may have misunderstood all of this…
At the earlier point in the pipeline where the plain white balance operates, the illuminant is D65 (approximately 6500K). At the later point in the pipeline where color calibration operates, the illuminant is D50 (approximately 5000K). So 4770K relative to a D65 illuminant represents approximately the same color as 3844K relative to a D50 illuminant.
So an observer who is in an environment lit by 6500K white light and is looking at a blackbody of temperature 4770K should perceive it as being approximately the same color as an observer in an environment lit by 5000K white light and looking at a blackbody of temperature 3844K.
Well discussed here in and around Nov and Dec time frame
WB Module to D65-then input profile-then color calibration to D50…
Quoted from AP posting in the thread linked above
“Don’t even try to compare temperature readings from both modules. Again, color calibration takes an input that is already pre-corrected by white balance and input profile.”
You could use the picked values in place of the default ones of ‘camera reference’ and see if that eliminates the tinge; it’d give you a warning, but that’s OK in this case.
Thank you very much for the fruitful hints and explanations. I learned something new regarding color management and color temperatures, but I suppose there is much more to learn. Regardings the greenish tinge I’ll need to dig inside … probably I need to correct the color coeff because for my camera it’s shown 2.915 for red, 1.0 for green and 1.392 for blue.
@dirksagwitz Those don’t look so bad…what camera?? For a few lumix cameras the CFA has two versions it seems and so RGB are not correctly mapped to their WB coefficients…Do you have a colorchecker by any chance??
I am using a Nikon D7100 and unfortunately I do not have a colorchecker available.
In the meantime I did some additional tests and the green tinge insn’t noticeable on all images, … I have the impression that my filmic settings, i.e. the white- and black-exposure settings do have an influence.
I think I found my mistake: if I choose the exposure range in filmic too high (e.g. 12-14EV) it’s very likely I can notice the greenish tinge especially in shadows. Reducing the EV-Range to e.g. 10EV brings much more clearance … even if the shadows / highlights will loose some details in that case.
Thank you all for your tips and hints!
If my daylight images initially show CCT as “(invalid)”, I normally reset/select to daylight with good results … but what is the understanding when daylight images show a CCT as black-body which also produces a good result.
I opened the NEF in rawproc, my hack processor, and processed it to linear RGB with the as-shot white balance multipliers and the libraw-supplied camera color primaries, and the bulk of the image looks fine. Particularly the stump, neutral shades of gray. It’s the part of the wall that’s only illuminated directly by the reflected light of the lawn that looks green.
That’s just a natural part of the scene, IMHO. “Correcting” this would require artificial manipulation of the colors; masking it will be challenging as the wall’s illumination gradually transitions to domination by the sky.
By the way, this is one of those rare exposures that really doesn’t require a non-linear tone mapping, looks fine to me in linear.
At this level I think as you say there are some natural elements to honour…like the blue you see in snow …in any case I don’t find it too extreme and using the picker to select a large portion of the wall in the light either in CC module or using legacy Spot WP cleans it up pretty much if the look is not what you want…IMO as one of the approaching 8 billion souls on earth
For sure CB is an approach I always find its a bit strong so I end up keeping the hue but dropping the saturation…you can do essentially the same with CC use the picker on the wall. Now depending on what it finds it may not offer custom but if not select it…this just give you the hue chroma sliders much like the CB module…in this case again keep the hue and tweak the chroma…zero chroma is zero correction…more applies it like color balance…I use this all the time as the absolute temperature values really don’t mean that much in the CC module. I prefer to tweak it with the hue chroma…see what you think…
Know what you mean, when I put a filmic curve in, the green cast became more noticeable. Took it out, and the loss of contrast took the punch out of it.
I’m finding a lot of this in sunny-day images, where the shadows get other interesting light. I guess this is where the film folk would be pulling out the spotlights…
