Are my images Green?

Started 5 months ago | Questions thread
Robin Casady
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Re: Excellent Test, Unexpected Results
In reply to MiraShootsNikon, 5 months ago

MiraShootsNikon wrote:

Robin,

Good test--with, at least for me, unexpected and confusing results. That's good for discussion, for sure.

Of the test scenarios you ran, I found your last most intriguing. I don't understand how you can have gamut warnings if you shoot and process in sRGB and then output in sRGB. Let me unpack that statement a bit.

It may be that there are colors beyond the sRGB gamut that your RAW data might have represented in a broader color space. But if you shoot / process your RAW in sRGB, you'd never know it (beyond just eyeballing color that appears "flat")! Or have I got that wrong?

Here's my hunch: there's a problem in your test methodology. In all three cases, when you bring your RAW into Lightroom, you're working with / looking at the ProPhoto RGB articulation of your photograph and then converting that articulation to its direct equivalents in a different space. You're never actually seeing the native sRGB (or AdobeRGB) articulation of RAW data in Lightroom.

In Lightroom you set the color space in Preferences. I know that this setting is used in exporting from Lightroom, but I don't know whether it is used in how the image is displayed in Lightroom. I expect it might not be.

There is not gamut warning option in Lightroom 5.5. You have to send the image to Photoshop to get gamut warnings.

My settings in Lightroom 5 Develop module were mostly zero. I set WB with the eyedropper on a middle grey square in the image. The Camera Profile was Adobe's Camera Neutral. Sharpening, NR, Tone Curve, etc. were turned off. Tone and Presence were zeroed out except for Saturation in the second test.

So, with very little modification, the images were sent from Lightroom 5 to Photoshop. For ProPhotoRGB I set the Lightroom 5 Preferences to ProPhotoRGB, and in Photoshop I set the Working Color Space to ProPhotoRGB. This was done before sending the image from Lightroom 5 to Photoshop. I changed both apps to each color space before sending the file over.

In Photoshop I toggled Gamut warning and carefully watched for all or part of each square to show the grey out-of-gamut warning.

With the Lightroom 5 Preferences set to ProPhotoRGB the image came into Photoshop as ProPhotoRGB. I checked gamut while it was still in ProPhotoRGB.

With the Lightroom 5 Preferences set to Adobe RGB the image came into Photoshop as Adobe RGB I checked gamut while it was still in Adobe RGB.

With the Lightroom 5 Preferences set to sRGB the image came into Photoshop as sRGB.

As far as I know (again, I could be wrong), you can't tell Lightroom to show you RAW in sRGB (or in AdobeRGB, or in any other gamut). You can only set Lightroom to output your results in other color spaces (e.g. when you send a frame to Photoshop or an external editor, or when you export). Or you can use soft proofing and see where pushing your ProPhoto RGB articulation into other color spaces (Adobe RGB, sRGB, your monitor's color gamut, your printer's color gamut) might result in clipped colors. But you're always looking at the ProPhoto articulation of color, even if some of those colors are clipped by relative colorimetric conversion to your monitor's gamut, etc.

This is why I did as little as possible in Lightroom 5.

To really compare the various scenarios, here, you'd need to actually see a smaller gamut's articulation of color. So here's an alternate test methodology:

(1) Shoot an Adobe RGB JPEG and convert it to sRGB (using a relative colorimetric approach)

(2) Shoot an sRGB JPEG. Leave it in the sRGB color space.

Compare.

Again, I might have this all bass-ackwards, but I really think you can't "set" Lightroom to show you RAW in sRGB or AdobeRGB--you can only tell it to output (or proof) its native ProPhoto RGB articulation to other spaces via a relative colorimetric approach.

And, good test--again, very thought-provoking.

I am only interested in working with NEFs in 16 bit. In-camera JPEGs are 8 bit, I believe.

In other to eliminate gamut warnings the saturation had to be reduced to levels below what looked right. For ProPhotoRGB it was -42 saturation. sRGB required -46 saturation.

Saturation +42 ProPhotoRGB to sRGB

Saturation -44 AdobeRGB to sRGB

Saturation -46 sRGB to sRGB

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Robin Casady

http://www.robincasady.com/Photo/index.html
"Get your facts first, then you can distort them as you please."
—Mark Twain

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