The yellow patch on the color checker looks good in the first shot, too muted in the second.

I think this is something different. See the heavy blue clipping in the histogram? That's a very dark yellow somewhere, and I think that's the key.

It's been my experience with all my Nikons over the years (maybe all DSLRs) that the blue channel is "weak" and goes to low clipping very easily. May have something to do with the Bayer pattern. The result is muddy, dark yellows that instantly look wrong (but it's hard to put your finger on it). One thing that shows this clearly is fresh foliage in spring, where the amount of blue light is very low.

I haven't really found a good solution to this. I just try to give as much exposure as possible, and deal with it in post.

But what I would do is experiment with different camera profiles. This is a case where you could also try to make your own profiles. You already have the Color Checker, so you just need to download the DNG Profile Editor.

Maybe so, and I'm no longer 20 myself...but I do recognize white when I see it.

I think what George is seeing is real, and the blue clipping is the smoking gun.

Based on what I said above, you'd think the solution was to increase blue level in the camera profile.  But once again it's not that simple. Blue is already at the correct level, it's just that it drops off the radar too quickly. That's what I mean by "weak" blue channel.

I agree with twenty_one that the image appears underexposed. In both posted images with LR corrections applied the histogram appears shifted to the left about -.5 EV. Since the ColorChecker is in the picture the white patch should appear in the histogram very near 100% or fully to the right.

George, what LR Basic panel settings are your using, and what if any Tone panel or Local Adjustments? I also assume you are using a ColorChecker Passport created camera profile. Did you create it from this picture?

If you have to make the same adjustments for all images, I think this means your profile needs adjusting.  If I understand correct, you are using a ColorChecker Passport profile.  It's been a while since I used the Passport software to generate profiles, but I don't believe you have the option of adjusting individual colors.  You can use the Adobe DNG Profile Editor to make the adjustments in the profile and maybe this will resolve your problem for this and all other images. 

Just a quick look at this now, have to run...

I brought the one you said "kind of worked" into Photoshop and boosted blue a bit in the shadows (Curves and Channel Mixer). This one's also heavily clipped in low blue. As I said earlier, I suspect this is the base problem. Look any better?

Well, it's not underexposure as such. It's actually a bit more complicated.

I'll have to use Photoshop to show what's happening here. This is how the green channel looks:

Nothing unusual there. But take a look at the blue channel:

The histogram confirms it:

Not only does the blue channe contain very little information, it also drops off to full clipping much sooner than the other channels. But just shifting the white balance towards blue doesn't help - then you get the opposite problem in the highlights. This is in fact the way it turns out when you eyedrop for correct white balance.

Visually, this lack of blue information translates to a heavy, unpleasant yellow without "air". I recognized George's problem here because I have struggled with it myself.

One thing that may help is to make a Tone Curve adjustment to the blue channel, something like this:

Or perhaps use the Split Toning panel. I do both, depending on circumstances. But that won't safeguard against clipping - for that you need to make certain to give adequate exposure to the shot so that you have headroom in editing.

Why this tends to happen to the blue channel and not the red (which has as many sites in the Bayer pattern), I just don't know.

Yes, that's better, although you're killing some of the orange, perhaps unnecessarily. But in the end you'll just have to try out different things and see what works best for your camera(s).

But I insist that you need to keep a close eye on the blue channel. That's where the problem is.

As for custom camera profiles, I haven't tried the x-rite software (never installed it) - only the DNG Profile Editor. But now that you mention it, the main reason I sort of gave that up in favor of the Adobe Standard profile, is that there was always at least one color "running off" and oversaturating to an unacceptable degree. Maybe 18 color patches simply aren't enough.

You're welcome

I've been there, so I knew what you were talking about. But try out all the things you can think of (and report back if you stumble on something) (that goes for everyone reading this BTW), because I'm still not certain this is the ideal solution.

I should say that I tend to underexpose things slightly (-1/3) because of my fear of blown out white coats, and this Nikon seems to allow plenty of editing leeway in the darks --more than it does in the lights. Same goes for several other Nikon models I've had.

Just out of curiosity: could you try (if you have time) to capture an  additional alternative frame where you deliberately overexpose, by an exposure compensation of +1/3 or 2/3 ? Does that really blow out your white dog coats? Irrecoverably?

I find with the 3 Nikons we use that such "cautious ETTR" tends to be pretty well suited for PV2012's image-adapted controls, in most situations.

I'd just be interested if you have this uneven channel clipping in the same degree.

Cornelia

No problem with those monitors. But 115 may be a little high for "very dim". It could also be a problem with the monitor profile itself, so recalibrate in any case.

So, it seems we have identified two different issues here:

1. The "dense" yellows caused by blue channel dropout from the camera sensor.

2. Underexposure caused by incorrect white rendering/perception (leave that open for now). Again, the whites you claim to be on the verge of blowing out, look muted and muddy to me with much to go on. If you go for a "film"/retro look it'll work, but for sparkle you need to pull up those whites.

b2martin_a wrote:

 

Why is this not a camera profile problem

Because the other profiles aren't any better. Here's another example from the "orchid project" I posted some examples from in another thread - and that shows the same problem with heavy yellows. First the reference shot on location:

(again I need to remind everyone that inline images in the forum are not color managed. Click to show correctly).

Adobe Standard:

Camera Neutral, same settings:

...and here's the final corrected version:

This is in the camera sensor. I assume it's possible to correct it with a profile, but the 18 color patches in the Color Checker is not enough. There's no way to correct shadows and not affect middle values, thus only creating new problems.

The reason I ask the question is because in post 16 above George in Seattle said with Camera Neutral it did not have the blue clipping issue and clicking to set white balance works better. 

twenty_one wrote:

 

 

But every custom profile I have made has had someproblem with oversaturation in somecolors. It just seems to "lose grip" at that point and the colors run off, so to speak. This can be adjusted in the DNG profile editor, but then you get into deep waters in a very time-consuming exercise and I'm simply not convinced it's worth the effort. Not as long as the Adobe Standard profile behaves as well as it does, despite the minor glitches.

I have the same issues, but with my Canon DSLR bodies the CCPP profile still looks the best. The problem is that for some images the color is not always accurate and/or detail is lost in the image (i.e. flowers, dog hair, etc.). I did a little research this morning to better understand what's happening. To do this I needed two vital pieces of information:

1) ColorChecker Passpot patch values, which is available here:

http://xritephoto.com/documents/literature/en/ColorData-1p_EN.pdf

2) File download of the ColorChecker with the actual values as specified above. Go to the below link, scroll down to 'ColorChecker Images" and download the ProPhoto 16 bit TIFF under the column

Derived from GretagMacbeth
L*a*b* D50 data
(June 2006)

http://www.babelcolor.com/main_level/ColorChecker.htm

3) At this point you are good to go for comparing your CCPP images in PS, but this link also provides the values for taking the readings in LR (created by our LR forum expert Jao):

http://lagemaat.blogspot.com/2007/09/more-precise-values.html

What I discover is that none of my CCPP images came close to matching the above derived target image, regardless if I used the CCPP, Adobe Standard, or Camera Standard profiles. Next I tried using the Basic tonal controls with the CCPP image and a profile created from it. I got a very close match for the grayscale patch values using the following settings:

Exposure = +.25, Contrast = -40, Highlights = -50, Shadows = 0, Whites = +30, Blacks = -40

Some of the colors in the CCPP adjusted image still did not match the derived reference chart when viewed in LR or PS.

After running this test I'm starting to look at Adobe Standard profile with a less jaundiced eye.

Using the above derived CC file download and CC patch values for PS and LR you can do your own testing and decide what works best.

I see you are taking a more scientific approach to this than I am

But notice the darkest blue - again. It's still oversaturated, and that's bound to give you problems. And this time yellow is undersaturated. There's something funny going on with the blue channel, maybe it's sensor technology, the Bayer array is a flawed concept to begin with, I just don't know.

Profiles work well output-referred, such as for monitors, since the source is reasonably well-behaved to begin with. But a scene-referred camera profile is a much more unruly beast.

In the end, however, it's worth remembering that cameras differ widely by brand, model and individual copy. This is something everybody has to work out with their own equipment.