Which RGB do you use?

[LocalHero1953]

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It would probably never worry me if I didn't print any myself, as long as they are seen using other media.

Welcome to the C21 and the age of the internet.😉

Edited April 28, 2024 by LocalHero1953

[jaapv]

There is also the postprocessing argument: If you work in a smaller colourspace, the "edge" colours get shifted into the smaller space and cannot be edited any more. If you use a large colour space during your editing (nearly) all colours will be edited properly and will only be converted to the smaller colour space when dumbing down at the end just before saving according to the intended use. That is the reason that Lightroom uses Prophoto in the background before setting the desired colour space in Export. There is no reconstructing an sRGB file back to a larger colour space. The conversion down is wholly destructive. 

I like to see my photographs in the full gamut on my Adobe RGB screen and print them on my Adobe RGB printer, even if the difference is subtle.

[kkcsm]

On 4/28/2024 at 1:56 AM, jaapv said:

The times are past tht we mainly used sRGB screens for our photos. Apple uses P3 which is approx. Adobe RGB, most quality screens that are sold for photo editing are more than 90% Adobe RGB, mostly 99-100% and it won't be too long before Prophoto screens become more or less affordable - although I do not quite se the usefulness there, as Prophoto exceeds the gamut of the human eye, especially in the blues. Times they are a-changin'...

I was reading through this thread wondering why nobody selected prophoto, I guess this is why?  I always work in lightroom in prophoto raw and export to sRGB jpg.  I figured prophoto is bigger, bigger is better, go with better 😉

I did not realize that regardless of the color space you choose, LR operates in prophoto mode...  And I kind of realized that my monitor could not display the full gamut, but I figured it would be close enough it wouldn't matter.  I did not know that prophoto exceeds the capabilities of our eyes.

I guess in the end it doesn't matter much to me, I have never been surprised by my converted files colors diverging from what I see while editing.  But I'm not as fussy about color as some people around here are.   

[thebarnman]

Here's an example of the color spaces.  I didn't realize the ProPhoto space includes areas humans can't see!  However I just read Lightroom keeps everything in the ProPhoto space for the most non destructive editing. 

I also learned "Lightroom Classic primarily uses the Adobe RGB color space to display colors."

So it's only when exporting is when the color space is reduced to Adobe 98 or what ever you want to use.  

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[LocalHero1953]

For editing I go for the widest possible gamut, even if that is beyond the capabilities of the human eye.

This is how I think of it (and I'm happy to be told I am misguided!).

Suppose the eye can see colours on a scale from 0 to 10, but your software can work in 0 to 20. Suppose some step in your editing processes (e.g. colour balancing) pushes one colour in your image up to 11 and another to 10. In a system limited just to what the eye can see, the first image colour will be clipped at 10, and so both colours will have the same value. Then when it comes to outputting the image to a printer or a sRGB JPEG, both colours will be identical. If you retained the full colour data, so that the two colour values are kept as 10 and 11, then the rendering system (which 'adjusts' the colours to fit into the output gamut) can and should visibly preserve the differences between the two colours.

[hansvons]

4 hours ago, thebarnman said:

So it's only when exporting is when the color space is reduced to Adobe 98 or what ever you want to use.  

Yes. And when viewing it on a display. This can be very apparent when looking at a proper full-gamut Rec2020 HDR monitor (rare breeds, cost 30k+).

[thebarnman]

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22 hours ago, LocalHero1953 said:

For editing I go for the widest possible gamut, even if that is beyond the capabilities of the human eye.

This is how I think of it (and I'm happy to be told I am misguided!).

Suppose the eye can see colours on a scale from 0 to 10, but your software can work in 0 to 20. Suppose some step in your editing processes (e.g. colour balancing) pushes one colour in your image up to 11 and another to 10. In a system limited just to what the eye can see, the first image colour will be clipped at 10, and so both colours will have the same value. Then when it comes to outputting the image to a printer or a sRGB JPEG, both colours will be identical. If you retained the full colour data, so that the two colour values are kept as 10 and 11, then the rendering system (which 'adjusts' the colours to fit into the output gamut) can and should visibly preserve the differences between the two colours.

Totally makes sense.  So now I'm wondering what color space is on the DNG file of a Leica SL3?  I'm sure it's probably greater than Adobe 98 or even possibly Rec. 2020.  As you can see, Rec. 2020 seems to have the best coverage at least in the range of human vision.  On the other hand, I now understand why ProPhoto would be useful if the camera can capture more than you see at least for editing purposes.    

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[thebarnman]

20 hours ago, hansvons said:

Yes. And when viewing it on a display. This can be very apparent when looking at a proper full-gamut Rec2020 HDR monitor (rare breeds, cost 30k+).

Part of the end uses I would like to do is to export digital files to Rec. 2020 to view on my 83" Sony A90J (calibrated) A90J.  It's capable of reproducing 72 to 73% of the Rec. 2020 color space.  Of course I would use Adobe 98 for prints and sRGB for web/emailing.

Unfortunately my old version of Lightroom does not have an export featuring Rec. 2020 but it does do Adobe 98 (which is close and slightly different than the P3 color space.)  My Sony A90J can reproduce 98% of the DCI-P3 color space.   

My new monitor the EIZO ColorEdge CG2700X (replacing my aging NEC) is also capable of Rec. 2020 but there's no information on what percentage of that it's capable of.  However, it can reproduce 98% of the DCI-P3 and 99% of the Adobe 98. 

I'm betting the percentage of reproduction is higher with the EIZO when compared to my TV when it comes to Rec. 2020 because my TV has white subpixels while the monitor does not.   

 

[hansvons]

1 hour ago, thebarnman said:

So now I'm wondering what color space is on the DNG file of a Leica SL3?

It has its own colour space, the SL3 colour space.

In colour science, there is the concept of display-referred colour spaces such as sRGB, P3, Adobe98, Rec709 (HDTV) or Rec2020, which are clearly defined by a specific standard, and there are scene-referred colour spaces, which are based on digital cameras, scanners, you name it. And then there are colour encoding systems like ProPhoto or ACES (Academy Color Encoding System), which are not connected to a specific device like a camera or display and thus don't run by the term colour space. Their job is to provide a huge digital space to encode, store and provide image data in the highest possible quality. ACES exceeds the human vision and is considerably larger than Rec2020 or ProPhoto. It can export to any colour space through an output transform node (and, vice versa, ingest the camera data through an input transform algorithm).

ACES is commonly used in high-end film production. Applications like C1 and others have their own, proprietary but similar colour encoding systems. LR seems to use ProPhoto. 

This Wikipedia article is a great starting point.

 

56 minutes ago, thebarnman said:

However, it can reproduce 98% of the DCI-P3 and 99% of the Adobe 98. 

If it can only reproduce 98% P3, it will never display Rec2020 in its full glory (there are only super expensive studio displays that can do that halfway properly). The same will be the case with your TV probably. If I recall correctly, proper Rec2020 requires at least 4,000 nits. What it can do is emulate Rec2020 signals and bring them down to their own colour space, which, in your Eizo's case, is a tad smaller than Adobe 98.

[jaapv]

And then, of course, we have the mother of all colour spaces, CIE L*A*B* which is basically not device-based and encompasses the full gamut of human vision plus a number of colours that cannot exist in an RGB type colour space. To gain a beginning of understanding we must fight our way throug a few head-ache inducing books by Dan Margulis, but if you google there are quite a few nice simplified articles to be found. 

 

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[erudolph]

A workmate at the video post house once said, “These days you need a PhD in the History of Consciousness to begin to color correct. 

[thebarnman]

On 6/11/2024 at 1:16 AM, hansvons said:

If it can only reproduce 98% P3, it will never display Rec2020 in its full glory (there are only super expensive studio displays that can do that halfway properly). The same will be the case with your TV probably. If I recall correctly, proper Rec2020 requires at least 4,000 nits. What it can do is emulate Rec2020 signals and bring them down to their own colour space, which, in your Eizo's case, is a tad smaller than Adobe 98.

Thanks for the Wikipedia article.  And wow, that ACES APO is something else! 

Sorry to say I couldn't find what percentage the studio display can reproduce of Rec. 2020; no mention of it at all.  However for much less, many of the short throw laser projectors costing much less can achieve about or close to 100% Rec. 2020 https://www.rtings.com/projector/reviews/formovie/theater and the new QD-OLED displays can reproduce 99.83% of P3 and 88.85% of the Rec. 2020 space so they say.  

Here's a list of other TV capable of Rec. 2020 listing what percentage of that they can display https://www.rtings.com/tv/tests/picture-quality/wide-color-gamut-rec-709-dci-p3-rec-2020 through there's only a few movies that take full advantage of it...mainly animated movies.  

It's interesting you mentioned a nit level to realize the full potential of Rec. 2020; 4,000 nits.  Yes, brighter display, more colors.  My A90J can only achieve about 820 or 840 nits within a 10% window or less.  So based from the first link I posted above, they're saying the realization is about a 5% difference at least according to the link above.      

  

[Doug A]

sRGB for color images. VueScan default. 

EPSON Gray - Gamma 2.2 for monochrome images. Recommended by an Epson rep helping me with an ABW issue. (It turned out to be a bad ink cartridge, not related to the ICC profile at all, but I left the setting alone anyway.)

[hansvons]

On 6/12/2024 at 11:49 AM, thebarnman said:

It's interesting you mentioned a nit level to realize the full potential of Rec. 2020; 4,000 nits. 

Rec 2020, or HDR, for that matter, is basically the same as Rec709 (regular SDR video) in terms of monitor gamma (contrast, gamma 2.4). Still, it adds a massive amount of extra headroom to the brighter part of the video signal. That much larger white roll-off leads to interesting new categories of highlights in colour grading, like specular highlights, which basically are nonexistent in regular SDR video. You need a super-bright monitor that can project this massive gamut. I don't know those stop numbers, but I could imagine that 10-12 dynamic range stops are needed to project a full Rec2020 signal properly.

When you see a proper Rec2020 HDR projection/monitor, you know it. It's not an incremental change but a massive jump with a big wow effect. Much more impressive than stepping up from HD to UHD.

[CharlesL]

ProPhoto in Raw Therapee and Picture Window Pro. Use final .tif for print. Convert to sRGB for online share.