Out-of-gamut problem with an M-D image?

[roydonian]

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Earlier this month I went on a photoshoot in London's Wanstead park. One member of the group was wearing a bright orange jacket - the sort of colour that is sometimes described as 'day-glo orange' or 'emergency orange'. When I tackled the task of processing the photos I'd taken on that day using an M-D Typ 262 fitted with a 5cm retractable Summicron still fitted with the UV/IR filter bought when it was used on my M8, I was in for a surprise. In several of my photos - processed in Capture One 4 software set to the DNG neutral ICC profile - that orange jacket appeared far too 'glowing', and with no texture showing. Some areas of the garment appeared in such bright yellow as to give in the impression that the wearer's shoulders and arms had been splashed with yellow paint! I downloaded a trial copy of Capture One 12, but this produced the same result. The only pics of him in which these odd effects were not present were those taken under heavy shade.

A version processed in Lightroom 6 was more successful, but showed a yellow shift in the jacket highlights, as did a version created using the latest version of RawTherapee.

The lack of texture suggested that the jacket had been badly overexposed, yet the orange did not have the washed-out appearance that I'd normally associate with overexposure. But checking the histogram showed the presence on a tall red 'spike' at the far right that could be partly 'tamed' by applying an exposure correction of between 0.5 and 0.8 (depending on which software I was using). I wondered whether the material from which the jacket was made had some weird form of reflectivity that was not obvious to the naked eye, but which the M-D sensor had problems in handling.

'Emergency orange' is reported to lie outside of the common colour spaces such as sRGB or Adobe RGB. A quick check of RawTherapee showed that the 'Clip out-of-gamut colors' box was ticked. When I unticked it, the jacket highlights lost their yellow hue and reverted to the same colour as the rest of the jacket - not quite the correct orange colour, but with a slight shift towards the red that was easily corrected by applying a WB tint of 1.07. So perhaps the problems I'd seen with Capture One and Lightroom are due to the way that these programs handle out-of-gamut colours.

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[pico]

Daylight fluorescent colors are truly strange. They reflect invisible UV light plus the color of the pigment, sometimes making it more luminous than white. And yes, RGB does not accommodate the range.

Edited May 18, 2019 by pico

[adan]

The picture you posted is overexposed. Not only is the man's extended hand (also a "light red/orange") blown out in the highlights - but on downloading your .jpg, there is nothing approaching "black" anywhere in the picture. The darkest tone has a brightness of "23," nowhere near close to "zero."

How did you light-meter the pictures? Did you set any exposure compensation?

When you say you adjusted exposure "between 0.5 and 0.8," - I hope you meant "minus 0.5 or minus 0.8." A plus-exposure change will push all the tones even closer to blown-out.

Additionally, the whole picture is excessively red - all the neutral grays and near-blacks (trousers and backpacks and such) read at least 10 points higher in red than in green and blue.

That can be from IR contamination, but since you used your UV/IR-blocking filter, we can mostly eliminate that as the problem. Buy the gentleman's red camera-strap padding is overblown, the shaded side of his extended hand is screaming red, and his face (the only other skin tone I can see much of) is also well to the "sunburnt" side.

It could just be faulty white balance. How did you set the white balance? "Auto" or "as shot" from Capture One or LR? Or did you use the eyedropper to click on those "known-gray" bits of clothing to get a custom WB appropriate to the scene? Is the white-balance set to the magenta (+ plus) side, looking at the software's secondary WB "tint" slider?

A slight - adjustment - to Pico's explanation of day-glo colors. They don't so much reflect UV as convert it to a visible color. Specific atoms/chemicals are chosen for the cloth dye which absorb UV photons, jump to a higher (unsustainable) energy state, and then release the excess energy as visible light photons (red-orange, or yellow-green, in varying proportions. Which, since it is now in the visible range, adds a lot of brightness, and is no longer blocked by a UV filter. Really not any different than the glowing colors of 1960s psychedelic "black-light" paints - same atomic-physics process.

Thus the light output is indeed higher than light reflected from a normal red, orange, yellow or green dye.

So - you have a scene that: is overexposed to begin with; with a cloth that already puts out an abnormally-high amount of red-yellow light, and a WB that also pushes red higher than other colors.

___________________________

...anyway, some suggestions to try, in LR (simply because I'm more familiar with Adobe's raw controls than C1).

- Not sure if the overexposure can be fully corrected in the jacket, but using "highlights" and "shadows" may give you better control of relative bright and dark areas than a global "exposure" change. But if desired, make sure you are reducing exposure (slider to the left of "0" <<<< )

- make sure the WB is actually corrected for neutrals. Click with the WB "eye-dropper" on the grays of the man with back to camera to set WB. Avoid "canned" and "auto" WB choices.

- go into the "Camera Calibration" panel and play with the sliders for Red Primary - both hue and saturation. Here are some examples from a picture including "emergency orange" traffic cones (not sure they are exactly yhe same color as clothing dyes - but still very troublesome). I show how that color chnage hue and amount of detail with various settings (NB: my shot Note this image is Canon 5D with Leitz 21mm Super-Angulon-R, but similar problem. Original underexposed in camera -0.66 stops, as well). You also want to switch to Leica's own profile ("Embedded") and adjust from that - Adobe's profiles also have a "red fetish" in my experience. The bottom-left version looks a lot like your jimmied red jacket.

If it's possible to upload your actual original .dng file, that would give us each a chance to try different settings with your original flexible data.

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[roydonian]

Andy,

Thanks for that long and detailed response. It is morning there in the UK, and I'm about to head off to London for the annual Photographica fair. So I'll respond at length when I get back.

This was only my second outing with the M-D, and as your observed, its metering system  overexposes.  One goal of the trip was to determine by how much. With the M9, a -0.3EV correction was frequently suggested, but I've seen -0.5, -0.7, or even -1 suggested for the Typ 240 and 262. The image I posted was not intended to represent a corrected/processed image, but to show as close as possible what the camera delivered. The only correction I made was to reduce the exposure.

Best regards,

Doug

[roydonian]

That last statement was not quite correct - I also had to select DNG neutral or its equivalent.

[roydonian]

As I said yesterday, the image I posted was not intended to be a corrected version, but to show the 'yellow-paint' problem as seen in the out-of-the-camera image. So the exposure had been only roughly corrected, and no attempt was made to set the optimum white balance. I should have made this clear in my original posting. I didn't upload the original DNG because our forum has a file size limitation.

I curious as to why this false yellow colour had been generated. Hours of experimentation with Capture One have shown that it could not be removed by changing the exposure, camera profile, or colour balance.

I'm a journalist. Forty years ago I would have been accompanied by a lensman, but in today's world the man with the notebook is expected to take his own pics. That orange-jacket photo showed a potential future nightmare - the presidents of Boeing and Scruggs Airways pose in front of the Boeing 767 at next month's Paris Air Show to announce an order to 50 aircraft, and decide to do this wearing orange high-vis jackets with the Boeing (or Scruggs) logo. All the other journalists get a useable photo (just as the other photographers on last week's outing seem to have had no problem with the orange jacket), but I get one that makes it look like the poor guys had been attacked by yellow-paint-wielding protestors. That's the sort of misfortune that would earn this poor freelance the sort of interview with a magazine editor in which coffee is not served.

Back in the film era, I would load my camera with whatever seemed the best film for the job, and my only decision on image processing was whether to get this done by Joe's Basement or Metro Imaging. (I preferred Metro because when I went to buy film, the counter staff could advise of the best emulsion to use for the task in hand - told that I heading off to an event organised by the Israeli ministry of defence, they regaled me with a sad tale of how an expensive fashion shoot in the Egyptian desert needed to be entirely restaged some weeks later using a different film type because the colour balance from the first attempt had been uncorrectably cool.)

In today's digital age, shooting in JPEG and relying on the camera get the exposure and colour-balance reasonably right is the basic modus operandi for a journalist, and this way of working has rather influenced my 'off-duty' approach to digital photography. Sergei Gorshkov, commander in chief of the Soviet Navy from 1956 to 1985, is reported to have a plaque on the wall of his office that read "Better is the enemy of good enough". Following this maxim, I set my M9, Digilux 3 and D-Lux Typ 109 cameras to produce both JPEG and raw files. Wherever possible I treat the JPEG as a  ready-to-use 'good enough' image, leaving the raw file as the 'In case of emergency, break the glass' solution for photos that need significant manipulation.

The 'as shot' white balance from the camera is almost invariably better the 'auto' version that the software offers. If this white balance is unacceptable, the only correction I normally make would be to 'pick' on something that is neutral or near-neutral - as a journalist it was often relatively easy to make sure than a piece of white paper or even my black-covered reporter's notebook had been included in the photo.

With the Leica M-D, there is no JPEG output, so Capture One and RawTherapee have become the equivalent of Joe's Basement and Metro Imaging - I use Irfanview to scan through the raw files and delete the obvious failures, then pass the others through one of these programs in order to generate JPEG versions. If one program has problems with one or more specific pics, the other will probably do a better job.

Perhaps I'm a bit of a digital philistine, but the reason that I moved to the M-D was the desire to escape from modes and menus, and return to the simplicity of film-era shooting. So I must confess to having as much desire to explore the many 'bells & whistles' of Capture One or RawTherapee (curves, tints, et al,) as I have of learning how to operate an E-6 processing machine. 

I've posted below the results of running the orange-jacket pic through RawTherapee, and making some initial corrections. The software has made a reasonable job of rendering the overexposed jacket and the burned-out hand, but the whites (such as the woman's shoes) show some magenta contamination. So the pic still needs some further work. The blacks are still not zero, reflecting the fact that in the real world, the darkest tones are rarely pure black.

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[lct]

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Always got overexposed reds with my M240. Only solution i know of is to underexpose and adjust red saturation and/or lightness in PP if needed. I would reduce red lightness in your case. FWIW.

[250swb]

On 5/20/2019 at 7:08 PM, roydonian said:

 

I've posted below the results of running the orange-jacket pic through RawTherapee, and making some initial corrections. The software has made a reasonable job of rendering the overexposed jacket and the burned-out hand, but the whites (such as the woman's shoes) show some magenta contamination. So the pic still needs some further work. The blacks are still not zero, reflecting the fact that in the real world, the darkest tones are rarely pure black.

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I'd have said it was a cyan/green colour cast you've got here, not magenta. Put the image into Photoshop and press 'Auto Colour' and the whole image becomes more balanced with the grey trousers in particular going from greenish grey to neutral.