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Getting sRGB Color Values from ProPhoto Photograph

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iSeek

New Member
Premium Classic Member
Joined
Jul 16, 2019
Messages
17
Location
California
Lightroom Experience
Intermediate
Lightroom Version
Classic
Lightroom Version Number
Photoshop 22.5.2
Operating System
  1. Windows 10
I'd like to pick a color from a photo I'm editing in PS and use some web-based tools to do things like find complementary colors. If I use the dropper in PS, it gives me an RGB code, but when I enter that code into the web page, the color looks quite different from in PS. From experimenting, I believe this is because the dropper is giving me RGB in the ProPhoto color space, whereas the web uses sRGB color space.

Assuming my diagnosis is correct, what's the best way to get the color code relative to sRGB space from a PS photo in ProPhoto space?

Details:
  • looking at web page Color Wheel - Color Calculator | Sessions College
  • in PS ProPhoto, red lipstick shows with the dropper as (160,93,78) #a05d4e. However, entering that code on the web page shows a brownish color (with hint of red).
  • pasting the picture into a new document in sRGB color space, dropper says the red lipstick is (225,94,97) #e15e61
 
RGB is RGB. If you pick a color in PS while using the ProPhotoRGB It will be displayed by a monitor that is calibrated to some (usually sRGB) colorspace. If the ProPhotoSRB value picked lies outside the sRGB envelop of the monitor it will be corrected by the monitor to the monitor color space since the hardware in not capable of displaying colors outside of the monitor colorspace.

ProPhotoRGB in Photoshop is a computational color space used by Photoshop.

If your monitor is calibrated, it will display colors close to true for the monitor color profile.

If you use a web browser that is not color managed, then it will display a different appearing color for the same pixel in PS which is colors managed

So, to get accurate rendering, you need a browser that is color managed and a monitor that is color calibrated
This website can help you see how well your browser and monitor conform.
http://regex.info/blog/photo-tech/color-spaces-page2

Sent from my iPad using Tapatalk
 
Color values of the same color are different for different color spaces, so you cannot enter color values taken from a ProPhotoRGB image and then expect to see the same color if you enter that in a sRGB photo. You can compare that with temperatures. The same temperature will be a different degree when expressed in Celcius, Fahrenheit and Kelvin.
 
Color values of the same color are different for different color spaces, so you cannot enter color values taken from a ProPhotoRGB image and then expect to see the same color if you enter that in a sRGB photo.

Thanks, that's what I am realizing, that an RGB values from one color space will not produce the same color in a different color space. I realize that's obvious to most of you, but I'm just starting to grok this.

What I wanted to do is to sample a color in PS from a ProPhoto RGB document/picture, and then be able to get RGB values that I could use with a web-based tool to calculate complementary colors (1). That doesn't work if I just sample with the PS dropper, I suppose because it's giving me the ProPhoto RGB values of the color.

Below, I show a screenshot from PS. My original photo is on the left, in ProPhoto RGB. I pasted that photo into the document on the right, which is sRGB color space. I sampled each document inside the black circle area of the lip, and got the two very different color codes for each document.

Is there a way to either
  • have PS display sRGB color values of a color sampled in a ProPhoto RGB document, or
  • outside of PS, convert ProPhoto RGB values to sRGB values?

sRGB-vs-ProPhoto_RGB-color_values-2.png
 
I don’t know if a “colorspace conversion calculator” exists on the web, but I would not be surprised. Photoshop can convert between colorspaces, so you could use Photoshop for this. Open an image that is in ProPhotoRGB, set a color sampler and then use ‘Edit - Convert to profile’ and choose sRGB. Now the color sampler will show the sRGB values of the point you sampled. Of course you could use a copy of the image, so you’ll have both. Like in your screenshot.
 
In Photoshop, you can try using the soft-proofing feature to provide the values in both color spaces at once. Here is what’s going on in the recording below:
  1. (Not shown) Set up soft-proofing. You can choose View > Proof Setup > Internet Standard sRGB, or View > Proof Setup > Custom and choose an sRGB profile for the Device to Simulate.
  2. In the Info panel, make sure the first sampler readout is Actual Color, and the second is set to Proof Color.
  3. Hover the pointer within the image. As you do this, the color values in the current color space and proof color space are displayed in the Info panel.
But what if you want to keep your eye on one specific pixel/sampling area, so the values don’t disappear when you move the pointer? That’s what the second part addresses:
  1. Select the Eyedropper tool.
  2. Shift-click the Eyedropper tool on your area of interest.
  3. In the Info panel, switch the color sampler #1 readout between Actual Color and Proof Color as needed.
  4. If you want to sample more areas persistently, add more samplers (repeat step 2).
Photoshop sampler ProPhoto RGB soft proof sRGB.gif


Note that the color value conversion might still be off a little because of other factors, such as the Rendering Intent selected in Proof Setup.

This also works in Lightroom Classic using its soft-proofing feature, but I’m not sure if the different tone curve that MelissaRGB uses would mess up the conversion.
 
Good suggestion. It will be complicated in Lightroom, not only because of the Melissa color space, but also because Lightroom displays colors in percentages when in normal mode (but in RGB values in soft proof mode): How Show RGB value from 0 to 255 and no in % ?
 
In Photoshop, you can try using the soft-proofing feature to provide the values in both color spaces at once. Here is what’s going on in the recording below:
  1. (Not shown) Set up soft-proofing. You can choose View > Proof Setup > Internet Standard sRGB, or View > Proof Setup > Custom and choose an sRGB profile for the Device to Simulate.
  2. In the Info panel, make sure the first sampler readout is Actual Color, and the second is set to Proof Color.
  3. Hover the pointer within the image. As you do this, the color values in the current color space and proof color space are displayed in the Info panel.
But what if you want to keep your eye on one specific pixel/sampling area, so the values don’t disappear when you move the pointer? That’s what the second part addresses:
  1. Select the Eyedropper tool.
  2. Shift-click the Eyedropper tool on your area of interest.
  3. In the Info panel, switch the color sampler #1 readout between Actual Color and Proof Color as needed.
  4. If you want to sample more areas persistently, add more samplers (repeat step 2).
View attachment 17388

Note that the color value conversion might still be off a little because of other factors, such as the Rendering Intent selected in Proof Setup.

This also works in Lightroom Classic using its soft-proofing feature, but I’m not sure if the different tone curve that MelissaRGB uses would mess up the conversion.

This is cool, thanks! I had never ventured into Proof Setup before. I couldn't get it to work for "Internet Standard sRGB", and it initially didn't work for Custom/sRGB until I unchecked the "Preserve RGB Numbers" box. I guess that by not preserving RGB numbers, that's what enables the ProPhoto-->sRGB conversion to be displayed in the dropper displays.
 
Not preserving RGB numbers means that the soft proof displays the proper conversion. RGB-values must change if you convert between color spaces and want to keep the appearance of the colors. I am not sure why that ‘preserve’ option exists at all, but I assume that Adobe added it so you can preview what happens if your image would be opened in a non-color managed application.
 
RGB is RGB. If you pick a color in PS while using the ProPhotoRGB It will be displayed by a monitor that is calibrated to some (usually sRGB) colorspace. If the ProPhotoSRB value picked lies outside the sRGB envelop of the monitor it will be corrected by the monitor to the monitor color space since the hardware in not capable of displaying colors outside of the monitor colorspace.

ProPhotoRGB in Photoshop is a computational color space used by Photoshop.

If your monitor is calibrated, it will display colors close to true for the monitor color profile.

If you use a web browser that is not color managed, then it will display a different appearing color for the same pixel in PS which is colors managed

So, to get accurate rendering, you need a browser that is color managed and a monitor that is color calibrated
This website can help you see how well your browser and monitor conform.
http://regex.info/blog/photo-tech/color-spaces-page2

Sent from my iPad using Tapatalk
>>>>>>This website can help you see how well your browser and monitor conform.


As Keanu would say - "Whoa...!" That's an AMAZINGLY helpful/scary website instant visual reference.

I've been experiencing a "heck-ish" issue between Lightroom and, well, anything ending up in JPEG.
"Edit in (Photoshop)," getting "ICC Profile description is invalid" screen warning. Did much running in circles trying to ditch what may have been corrupted basic profiles on my Dell XPS laptop XPS 15" 9560 which is supposed to be a very accurate gamut/saturation panel. Problems came when connected to my ACER EB321HQU monitor. Running between 'extended' and 'mirrored' displays had different results.

Basically the colours were very red-shifted outside of Lightroom so I couldn't tell what was accurate. Had to try to switch/set color profiles for laptop and monitor to be equal. Still trying.

Never had the issue with my old HP tower (granted...only 1 monitor option as opposed to laptop docked in b/c a laptop...has its own screen).

Anyway, interesting forum thread reading!
 
In Photoshop and Lightroom reading numbers (ProPhoto/AdobeRGb/sRGB etc.) has nothing to do with the screen used.
Reading numbers goes to the file and graphic card so you get the same numbers if your screen by accident turn off your blue pixels or are in "wrong" colours.

Using a camera you always get a Colour space, sRGB, adobe rgb. Choosing RAW in your camera you have to chose you cold space during Import might chose sRGB or Adobe RGB (ProPhotoRGB).
Checking picture and Histogram on the camera screen are alleways in sRGB, even if you have chosen Raw in camera setting. Thus choosing HighLight and Shadow warning in camera you will ofte se a wider gamut for Highlight and Shadow when imported in Lightroom.
Using a scanner you often have to yourself give picture file a ColourSpace.

If you want to have same consistent colorer workflow between your units you have to buy a Monitor Calibrator (T.ex. X-Rite) and calibrate your screen.
Calibrating your screen, calibrate your screen TOGETHER with your computers graphic card, som moving your screen to another computer demands new calibration.
 
In Photoshop and Lightroom reading numbers (ProPhoto/AdobeRGb/sRGB etc.) has nothing to do with the screen used.
Reading numbers goes to the file and graphic card so you get the same numbers if your screen by accident turn off your blue pixels or are in "wrong" colours.

Using a camera you always get a Colour space, sRGB, adobe rgb. Choosing RAW in your camera you have to chose you cold space during Import might chose sRGB or Adobe RGB (ProPhotoRGB).
Checking picture and Histogram on the camera screen are alleways in sRGB, even if you have chosen Raw in camera setting. Thus choosing HighLight and Shadow warning in camera you will ofte se a wider gamut for Highlight and Shadow when imported in Lightroom.
Using a scanner you often have to yourself give picture file a ColourSpace.

If you want to have same consistent colorer workflow between your units you have to buy a Monitor Calibrator (T.ex. X-Rite) and calibrate your screen.
Calibrating your screen, calibrate your screen TOGETHER with your computers graphic card, som moving your screen to another computer demands new calibration.
For my own issue here, this is definitely the part I'm not closing loops on, because I have calibrated my screens. Both laptop and external monitor. But the symptom now of not being ABLE to switch (sorry...Photoshop not Lightroom discussion here on a tangent now) Color Settings off of ProPhoto is just bizarre. I've updated the application so kinda lost. I'll probably uninstall both Adobe Products here and then have to again try (grr) to find a combo that works under my machine/operating system. Always a fun combo of standing on one leg and scratching right ear with left hand trying to find the LR version that plays nice (really, my last best 'stable' version was 9.4 on the old PC).

Anyway--- digression here. Thanks, Kierphoto for the reminder to watch for a chosen color space at input stage of LR. Going to go back to my own thread :)
 
Color spaces.

The color rendering from the native chip in your pro camera goes far wider than ProPhoto rgb, reaching out to both infrared and ultra violet.

To limit to photographic use, both highpass filter and computing correct it down to no a standard (CRW,NEF etc.) RAW format numbers.

I have the suspicion that the vise thing in Lightroom (or other programs where you save the RAW file.) is you always can go back to these “original” RAW numbers, if we invent new color spaces in the future.

Today we start with the image on either Windows or Mac computers.

Windows computers, tablets and phones are made of many different factories and their color rendering are very different and often to the blue side or saturated side. For photographic use they severely need calibration or your printed pictures might be too warm and too dark.

Mac has a standard approved color rendering, so that today all their products
have the same colour rendering leaving factory. Not so far from a calibrated screen.


Screen colours:
Wide gamut are the maximum colours your screen can produce. On private TV screen you aften see these oversaturated colours.

For Photographic use:
ProPhoto was wisely invented by Kodak to foresee improved screen and printing equipment. On the High-end Epson printer you can print very closely to ProPhoto images witch even exeeds what you might see on the best Adobe 98% screens.

AdobeRGB was invented, for converting to absolute best color rendering to CMYK printing profile for high class printing on finest white paper with optical brightener and possibility to add a 5th printing colour. (Here sRGB was to small)

sRGB are the standard colorspace for normal computer screen, bot are no guarantee for correct colours, unless screen is calibrated Even calibrated sRGB works excellent for most purposes.


Correct Colors.
Are colours edited from a calibrated screen and printer (x-Rite iOne or Spyder etc.) Best situation if edited on a screen showing 98% of Adobe RGB.
 
I have the suspicion that the vise thing in Lightroom (or other programs where you save the RAW file.) is you always can go back to these “original” RAW numbers, if we invent new color spaces in the future.
Programs like Lightroom never change the RAW file. The RAW file data consists of numeric values for each photo site. Colors are inferred because each photo site had a Red, Green, or Blue filter over that photo site of the sensor. Programs like Lightroom demozaic the RGGB pattern to produce color pixels. This result is always stored as another file. The original has no color space and the resulting RGB image has a colorspace defined (in the case of Lightroom using ProPhotoRGB).

Any color space defined in the camera only applies to the RGB derivative JPEG (thumbnail or final JPEG) and never the original RAW photo site data.
 
Programs like Lightroom never change the RAW file. The RAW file data consists of numeric values for each photo site. Colors are inferred because each photo site had a Red, Green, or Blue filter over that photo site of the sensor. Programs like Lightroom demozaic the RGGB pattern to produce color pixels. This result is always stored as another file. The original has no color space and the resulting RGB image has a colorspace defined (in the case of Lightroom using ProPhotoRGB).

Any color space defined in the camera only applies to the RGB derivative JPEG (thumbnail or final JPEG) and never the original RAW photo site data.
Oh yes Clee. I just tried to keep it very simple for this forum.
All sensors are working in black and white/greyscale. So every pixel are just an old fashion lightmeter. Colors come from the RGB "painted" on each pixel.
Reading these colors and black reference are different from different camera brands even with the same Sony or KAF sensor etc.
That's is the reason you have the many Raw formats, NEF, CRW and many more.
Lightroom needs the new "key" to the color readout, every time there is introduced a new digital camera with en new chip.
 
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