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Author Topic: DSLR testing sites like DXOmark and Imaging Resource use HMI and LEDs for color  (Read 55956 times)

Tim Lookingbill

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Yes, many saturated yellows even in well known studio scenes are typically way out of gamut (e.g. out of Adobe RGB).

Jack

That's a surprise because I always thought yellow was more hobbled by the display gamut than its encoded color space but then for me it's quite often difficult to determine perceptually until I hit a brick wall getting the yellows to look correct either from my memory or comparing to a lit target.

The custom DNG Soraa profile didn't make much of a dent in making the yellow look bright, vibrant and in the correct hue compared to shooting the French's Mustard bottle outdoors in direct sunlight which does render the correct hue but not in vibrance or luminance as rendered by the Soraa which of course is an artificial light. To get as close as possible to the actual Soraa lit target scene shown in the example below I just used the dual illuminant made using daylight lit and tungsten lit CCchart. It corrected the appearance of the blue on the mustard bottle.

The sun's rendering should be the standard for accurate color appearance but if an artificial light as the Soraa LED plays perceptual tricks employing colorant and filtering mechanisms that enhance what the sun can't, I don't see much use of a custom profile for that particular light.

The yellow that is off is the ink printed on top of the yellow plastic bottle. It's not commercial offset CMYK ink (no halftone dots) and appears to be a custom mix similar to Pantone and probably a proprietary formulation. None of my edits in the Raw capture could duplicate the vibrance, brightness and hue.

To show where this yellow resides on the luminance scale which has a major influence on color gamut size the point curve inset shows I'ld have to clip the heck out of the yellow and still not make it look correct.

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digitaldog

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That's a surprise because I always thought yellow was more hobbled by the display gamut than its encoded color space but then for me it's quite often difficult to determine perceptually until I hit a brick wall getting the yellows to look correct either from my memory or comparing to a lit target.
W??T??F? What encoded color space???  :o
Well at least using proper tools, I see my display color gamut exceeds an sRGB encoding (of anything) in yellows. And more. Encode in ProPhoto RGB, something that exceeds Adobe RGB (1998), of course it is 'hobbled' (it's called clipped) of my display color gamut.
Wireframe is sRGB. Encode any image in sRGB, you can't go (color) outside the lines, just like when you play with crayons  ;D
Solid and colored is my display profile color gamut. Larger in yellow! Sure, green is massively larger but none the less, yellow is too.
It does help to actually have tools to see this stuff instead of guessing.
« Last Edit: June 27, 2018, 07:28:41 pm by digitaldog »
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Tim Lookingbill

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Let me reiterate for those that focus on the wrong point I'm making.

I'll put it simply that the printed yellow on the French's Mustard bottle lit by the Soraa LED spot light is glowing bright in luminance (maintaining hue) compared to the yellow plastic surround of the bottle much like the fluoresce effect of the green leaves I demonstrated several posts back.

Anyone who wants to split hairs explaining this in an argumentative manner using obscure color science jargon that no one can connect to a real and visual practical example as I demonstrated using edits of actual images, I consider not helpful.
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digitaldog

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Let me reiterate for those that focus on the wrong point I'm making.
We can only focus on your actual writings.... By all means reiterate and clarify. You haven't yet. You actually typed text combing one color space (I always thought yellow was more hobbled by the display gamut) with something that's the same (than its encoded color space) which makes no sense. Do you understand what encoding is? Are you talking about two color spaces, the display and? ??? If so, what's the 2nd color space that's 'hobbled' (a word that has no meaning in the discussion of color)?

hobbled; past participle: hobbled
1.
walk in an awkward way, typically because of pain from an injury.
"he was hobbling around on crutches"
synonyms:   limp, walk with difficulty, walk lamely, move unsteadily, walk haltingly; More
2.
tie or strap together (the legs of a horse or other animal) to prevent it from straying.
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Anyone who wants to split hairs explaining this in an argumentative manner using obscure color science jargon that no one can connect to a real and visual practical example as I demonstrated using edits of actual images, I consider not helpful.
We can only take your text as written, no argumentative manner (confusing by your own use of non color science jargon language). "No one can connect" only means, unless everyone posts, that you cannot connect. Sorry. If you want your readers to take your questions/writings seriously, ask them/comment without such ambiguities and language that has so little to do with this topic of color.
Meanwhile, the facts about a display color gamut, the color yellow, clipping compared to sRGB has been show visually, without any jargon.
« Last Edit: June 27, 2018, 09:14:14 pm by digitaldog »
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digitaldog

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Let me reiterate for those that focus on the wrong point I'm making.
Yes, I agree about that.  ;D
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digitaldog

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The yellow that is off is the ink printed on top of the yellow plastic bottle. It's not commercial offset CMYK ink (no halftone dots) and appears to be a custom mix similar to Pantone and probably a proprietary formulation. None of my edits in the Raw capture could duplicate the vibrance, brightness and hue.
And yet, when I measure the French's Classic Yellow mustard bottle (plastic, of course no halftone dot), I get these Lab values from an i1Pro using M0:
Lstar 81.09   astar 6.38   bstar 67.57   
And now let's plot that lab value against sRGB in 2D (all we need) and we can see, it falls easily within sRGB. Examine one yellow 'dot' within the sRGB gamut triangle. Again, no assumptions, actual colorimetry at play.
Further, I don't find this mustard to be very tasty but that's a subjective analysis. The colorimetry however, isn't!!!
Once again we see posting that illustrates that if you've only imagined it, you haven't experienced it. Now that I've experienced the mustard and it's actual measurement, we can move on to fact based discussions of color.  ::)
« Last Edit: June 28, 2018, 03:33:01 pm by digitaldog »
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digitaldog

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Horrors: the actual label, which under a loupe does show a dot pattern, is just outside sRGB color gamut. Which is why I don't suggest ENCODING raw captures into sRGB!
OK, done with Mustard and issues of color gamut of French's for those who insist on using sRGB.
Lab values of label is 85.07/14.31/96.50   

"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind".
-Lord Kelvin

To show where this yellow resides on the luminance scale which has a major influence on color gamut size the point curve inset shows I'ld have to clip the heck out of the yellow and still not make it look correct.
Only if you keep assuming it does.
« Last Edit: June 28, 2018, 03:29:20 pm by digitaldog »
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Doug Gray

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Horrors: the actual label, which under a loupe does show a dot pattern, is just outside sRGB color gamut. Which is why I don't suggest ENCODING raw captures into sRGB!
OK, done with Mustard and issues of color gamut of French's for those who insist on using sRGB.
Lab values of label is 85.07/14.31/96.50   

"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind".
-Lord Kelvin
Only if you keep assuming it does.

The measured color would apply to scene referred images. Of course output referred images will often be more saturated hence the need for wider gamuts than sRGB.
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digitaldog

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The measured color would apply to scene referred images. Of course output referred images will often be more saturated hence the need for wider gamuts than sRGB.
Which again is why I don't suggest ENCODING raw captures into sRGB!
A few folks posting here will recall this discussion:
https://www.dpreview.com/forums/post/59559609
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Doug Gray

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Which again is why I don't suggest ENCODING raw captures into sRGB!
A few folks posting here will recall this discussion:
https://www.dpreview.com/forums/post/59559609

:)
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Frans Waterlander

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Which again is why I don't suggest ENCODING raw captures into sRGB!
A few folks posting here will recall this discussion:
https://www.dpreview.com/forums/post/59559609

Oh yes! The unknown member!
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digitaldog

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Oh yes! The unknown member!
You blind too? Do you know how to read a post there, examine the sig? Seems not. Thanks for the thread hijack. Another person who hasn't the colorimetric tools or understanding to use em!  :o  \

Figure out yet how to read an Epson Nozzle check?  ;)
« Last Edit: June 28, 2018, 08:04:59 pm by digitaldog »
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Frans Waterlander

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You blind too? Do you know how to read a post there, examine the sig? Seems not.

The joke was apparently lost on you.
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Tim Lookingbill

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Horrors: the actual label, which under a loupe does show a dot pattern, is just outside sRGB color gamut. Which is why I don't suggest ENCODING raw captures into sRGB!

You've got the wrong French's Mustard Bottle (mine does not show a dot pattern in the printed yellow field: see image below shot through a loupe).

Also you need to light it with the Soraa to see that the light and ink combo is beyond reproduction through normal digital capture and processing even when applying edits.

Stay focused on my points and you won't have to do so much work.

Just to make it crystal clear since I didn't mention it earlier, I process/edit Raw captures in 16 bit ProPhotoRGB.
« Last Edit: June 29, 2018, 05:58:24 pm by Tim Lookingbill »
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digitaldog

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You've got the wrong French's Mustard Bottle (mine does not show a dot pattern in the printed yellow field: see image below shot through a loupe).
Nonsense, now you're going to tell us that the plastic and the label (which does have a dot pattern) vary based on the bottle size? What Lab value measurements you get from YOUR bottle? Oh, you can't conduct such measurements!  :o
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Also you need to light it with the Soraa to see that the light and ink combo is beyond reproduction through normal digital capture and processing even when applying edits.
No, I don't. But it's possible to comment on your inability to edit your raws! No matter the working space.
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Stay focused on my points and you won't have to do so much work.
Dismissing your admitted fiction (and the admitted wrong points your making) on the topic of color isn't at all work and rather fun!
Rule on holes Tim, when you're deep in one, stop digging.
« Last Edit: June 29, 2018, 06:03:42 pm by digitaldog »
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Tim Lookingbill

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Compare apple to apples.

I'm not the one who finds it necessary to argue something I see with my eyes which is what most folks use to check a color match from the original to the final print viewed under lighting.

I'm not even seeing a match on my display with the Soraa light.

And for the love of god, Andrew, could you please learn some decent processing skills? That French's bottle is off in all colors. Why so much red in the plastic bottle. That's not even a match on a display.
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Iliah

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> you need to light it with the Soraa to see that the light and ink combo is beyond reproduction through normal digital capture and processing even when applying edits

I'm not sure what is it that are you suggesting, is it that Soraa 5000K Vivid spot LED are not suitable for photographic reproduction purposes?
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digitaldog

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Compare apple to apples.

I'm not the one who finds it necessary to argue something I see with my eyes which is what most folks use to check a color match from the original to the final print viewed under lighting.

I'm not even seeing a match on my display with the Soraa light.

And for the love of god, Andrew, could you please learn some decent processing skills? That French's bottle is off in all colors. Why so much red in the plastic bottle. That's not even a match on a display.
I haven’t processed anything here Tim, I did what you cannot; measured the bottle and label to prove one falls completely into sRGB and the other just outside it. As to what you can and cannot match on your display, I suspect you may be struggling with display calibration as much as you struggle with editing your raws.
It's your burden if you insist on using an illuminant that kind of sucks, that you cannot colorimetrically evaluate (which IS the discussion here for those that can), that you assume a color falls outside a color gamut you cannot analyze, that you think the display color gamut is an encoding and all the rest of the silly text you've provided here that have been shown to be wrong or at best, massive assumptions on your part. Must you dug that hole deeper? Do you really think other than maybe one guy who just hijacked this thread yesterday, equally unable to measure color, anyone is taking you seriously? Please, stop flogging yourself in public. You're hobbling along here. ;D
« Last Edit: June 29, 2018, 06:15:07 pm by digitaldog »
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digitaldog

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> you need to light it with the Soraa to see that the light and ink combo is beyond reproduction through normal digital capture and processing even when applying edits

I'm not sure what is it that are you suggesting, is it that Soraa 5000K Vivid spot LED are not suitable for photographic reproduction purposes?
What ever he's suggesting, it's massively based on assumptions. I'm not sure he knows what he's suggesting either. 
He's assumed the shot of my mustered bottle is processed when it's a JPEG straight from an iPhone simply to show the bottle next to a device he doesn’t own or know to use, that I used to measure the plastic and label.
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Tim Lookingbill

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> you need to light it with the Soraa to see that the light and ink combo is beyond reproduction through normal digital capture and processing even when applying edits

I'm not sure what is it that are you suggesting, is it that Soraa 5000K Vivid spot LED are not suitable for photographic reproduction purposes?

Not with all colors if one wants an exact match especially with paintings in combination with the lighting viewed under. I've had the same issues with the 6 pigment phosphor technology of the 5000K 95CRI Ottlight 100wt HD CFL but at least with that I could generate a color match on my display with common objects like an old deck of cards, OB paper but I didn't have the French's Mustard bottle at the time.

And that's really been my main point which is there needs to be a broader choice of color targets when using any brand of lighting with fine art painting repro both artificial and natural. Just because someone comes out with a brand new wizbang full spectrum artificial white light and it measures perfectly with some spectro it doesn't mean it's going to reproduce exactly all possible paint formulations used in paintings.

It might even look great as a fine art painting viewing light but not necessarily be ideal for capturing and processing digitally what we see in combination with the light and the painting.
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