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  #21  
Old 14-06-2013, 07:10 PM
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Originally Posted by RickS View Post
Even high end monitors designed for colour critical work need calibration. The Dell monitor probably has defaults that make it look "good" i.e. bright and flashy.
Yep, that's exactly what Dell has done with many of their large panel LCDs. They made the mistake of shipping their 3008WFPs in wide gamut mode by default with no pre-calibrated sRGB profile. Those poor support guys!

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Originally Posted by RickS View Post
With no colour management the RGB values are just sent directly to the screen to interpret as it sees fit. Say you have an 8-bit colour which is completely green <0,255,0>. On a screen set to sRGB gamut this will give you the maximum green. On a screen set to AdobeRGB gamut it will be the maximum green in that wider gamut, i.e. more saturated.

So, what you are seeing is what I'd expect...
I think that's exactly it.

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Originally Posted by philiphart View Post
I can understand that change if I was looking at an Adobe RGB file in Photoshop, where the monitor in sRGB mode couldn't display the gamut but it could in Adobe RGB mode.
Phil, colour management on desktop computers is (unnecessarily) confusing. The colours that you see looking at an image in Photoshop goes through a chain of three layers of processing:

1. Your monitor's settings, e.g. native or pre-loaded calibration curves (such as the sRGB and Adobe RGB setting you were looking at).

2. The operating system's colour profile for your monitor. This creates a mapping between the RGB numbers and the physical colour that your monitor actually displays.

3. The soft proofing profile being applied by Photoshop. This is used to simulate one device on another, e.g. using your monitor to simulate what a print (with reduced gamut) might look like.

It's generally best to turn off #3 (i.e. disable soft proofing in Photoshop) at the start so it's less confusing.

When you changed the colour space setting on the monitor to say Adobe RGB, that changes #1. However, the operating system still thinks you're in sRGB mode so it's sending RGB data in sRGB format to the monitor... hence why you get the colour shift. When you change your monitor setting to Adobe RGB, at the same time you also need to go into the colour management settings (I *think* it's under Control Panel -> Displays in Windows... I don't recall off the top of my head) and change the colour profile for the monitor to Adobe RGB.

Once you've adjusted #1 and #2 simultaneously, you shouldn't get a colour shift - but in some images you might be able to notice slightly richer saturation.

If you colour calibrate a monitor, you basically set the monitor to its "best" custom setting (#1), and the calibration device physically measures the colours and creates a new colour profile for the operating system to use (#2). This way, you can maximise the capabilities of what the monitor can display.

tl;dr when you change your monitor to Adobe RGB mode, you also have to change Windows/OS X to Adobe RGB mode for that monitor
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  #22  
Old 14-06-2013, 10:57 PM
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philiphart (Phil Hart)
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Originally Posted by naskies View Post
When you changed the colour space setting on the monitor to say Adobe RGB, that changes #1. However, the operating system still thinks you're in sRGB mode so it's sending RGB data in sRGB format to the monitor... hence why you get the colour shift. When you change your monitor setting to Adobe RGB, at the same time you also need to go into the colour management settings (I *think* it's under Control Panel -> Displays in Windows... I don't recall off the top of my head) and change the colour profile for the monitor to Adobe RGB.

Once you've adjusted #1 and #2 simultaneously, you shouldn't get a colour shift - but in some images you might be able to notice slightly richer saturation.
Thanks.. that's about where I got to as well. You have to dig a fair way in the control panel (choose Advanced settings twice) to change the Monitor profile but I'm going to experiment a little with that.

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Originally Posted by naskies View Post
If you colour calibrate a monitor, you basically set the monitor to its "best" custom setting (#1), and the calibration device physically measures the colours and creates a new colour profile for the operating system to use (#2). This way, you can maximise the capabilities of what the monitor can display.
The downside to doing this is that you start to see your own images a fair (/little) bit differently to the rest of the world viewing them in sRGB colour space on sRGB enabled hardware. But if you don't do this, then there's not a lot of value in working in Adobe RGB in Photoshop anyway.. except I guess that your colour management enabled local or online printer can do a little more with them etc.

oh well.. i'm learning again.. thanks for the comments.
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  #23  
Old 15-06-2013, 03:04 PM
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So I have successfully changed the Dell monitor to the factory calibrated Adobe RGB and at the same time changed the Win7 operating system monitor profile to Adobe RGB. I have to restart Photoshop but can then see that it reflects the new Monitor Profile as well.

Now my gaudy bioluminescence images have the same level of saturation in Photoshop in this Adobe RGB mode as they did beforehand viewing with monitor and OS working in sRGB mode.

The problem now is that viewing the images online in Chrome they all look over-saturated, because Chrome ignores the OS monitor profile. They look fine in Firefox which recognises and honours the new monitor profile.

There is mention online of the command line switch "--enable-monitor-profile" for Chrome which apparently worked in some earlier versions of Chrome but is not effective for me now (Chrome 27).
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  #24  
Old 15-06-2013, 03:30 PM
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Octane (Humayun)
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Phil,

Was it just a matter of choosing the Adobe RGB profile in the advanced-advanced settings in the display section of Control Panel?

Did you change any of the other intents?

H
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  #25  
Old 15-06-2013, 03:54 PM
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Originally Posted by Octane View Post
Phil,

Was it just a matter of choosing the Adobe RGB profile in the advanced-advanced settings in the display section of Control Panel?

Did you change any of the other intents?

H
I was working off these instructions eventually (top post):

http://forums.whirlpool.net.au/archive/1511987

Under Color Management, on the Devices Tab, tick "Use my Settings for this Device" and then use Add button and choose Adobe RGB. I didn't change anything under the Advanced tab (not once I realised I didn't need to anyway).

For the moment I've switched everything back to sRGB. The Chrome issue is significant so I'll have to think about that.. I'm not keen to switch back to Firefox. If I want to switch to Adobe RGB and keep it that way then I'll also need to recalibrate brightness/contrast on the monitor as my images in Lightroom look a little too bright/flat/low contrast without adjusting that to match.

I'm happy with what I've learnt along the way (thanks Rick, naskies et al) and that I'm not actually missing out on too much. Windows in general looks way over-saturated with the monitor in Adobe RGB mode, even though my images look fine with the correct monitor profile.
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  #26  
Old 15-06-2013, 03:59 PM
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Looks like this..
Attached Thumbnails
Click for full-size image (Capture.PNG)
87.1 KB16 views
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  #27  
Old 15-06-2013, 06:40 PM
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Thanks, Phil.

I've got a 30" Apple Cinema Display and will likely buy the new Mac Pro to hook it up to. But, in the meantime, I'll play with this.

H
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  #28  
Old 15-06-2013, 08:42 PM
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The 30" ACD falls substantially short of the AdobeRGB gamut, in particular in the green and cyan. It does cover (even slightly exceed) most of sRGB, though, except for the saturated magenta range. Hence, no amount of arm twisting is going to make AdobeRGB tagged images look real, if and when they contain those saturated greens and cyans. Something's gotta give. That's where rendering intents come into play, which let you choose the lesser evil for your purpose.

You can choose between accurately displaying those colours that can be displayed while dropping the undisplayable colours on the floor (colorimetric), or shifting and squeezing everything around to achieve a similar overall look (perceptual).

The actual working space of image editing software is always XIE or Lab, and floating point, only when you ask the software to display integer RGB values (like with the eye dropper) it'll convert the real colour (XIE or Lab) into the corresponding values from your chosen colour space. It does not matter what space that it, the software will always reverse-apply the display device profile to make up for the display's shortcomings and show the image as accurate or realistic as possible on your screen, depending on the rendering intent. That's true for colour managed systems anyway, which I believe all OSes in this day and age are? Mac OS certainly is.

To deal with not colour managed web browsers, which apparently a large number of people still use, it is safest to convert the image RGB values into the sRGB space. Most displays can be set to respond like something close to sRGB. Also, colour managed browsers will assume sRGB if an image isn't tagged with any colour space at all.

Cheers
Steffen.
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  #29  
Old 15-06-2013, 08:47 PM
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Originally Posted by philiphart View Post
The downside to doing this is that you start to see your own images a fair (/little) bit differently to the rest of the world viewing them in sRGB colour space on sRGB enabled hardware. But if you don't do this, then there's not a lot of value in working in Adobe RGB in Photoshop anyway.. except I guess that your colour management enabled local or online printer can do a little more with them etc.
The rest of the world should. Yes sRGB is the default profile of the web but every browser on the market now extracts the embedded profiles from images for display. They should see the same image as you to the point where their hardware gives up and then the colours will lock at the nearest saturated value. Let them retard their hardware, don't retard yours to appease them

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Originally Posted by philiphart View Post
So I have successfully changed the Dell monitor to the factory calibrated Adobe RGB.
A far better approach would be to put your monitor into a native setting if it has one and then download the correct colour profile for it. Having wide gamut monitors retard their performance to match the working space of an image defeats the purpose of colour management.

The only profile your monitor should have is the one the manufacturer gave you or the one you've generated through the use of a calibration device.

Quote:
Originally Posted by philiphart View Post
There is mention online of the command line switch "--enable-monitor-profile" for Chrome which apparently worked in some earlier versions of Chrome but is not effective for me now (Chrome 27).
Yep sucks doesn't it. You need to Firefox.
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  #30  
Old 15-06-2013, 08:49 PM
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Quote:
Originally Posted by Steffen View Post
To deal with not colour managed web browsers, which apparently a large number of people still use, it is safest to convert the image RGB values into the sRGB space. Most displays can be set to respond like something close to sRGB. Also, colour managed browsers will assume sRGB if an image isn't tagged with any colour space at all.

Cheers
Steffen.
The problem is that even viewing sRGB images online, if the monitor is set to Adobe RGB but the browser is ignoring the monitor profile in the operating system setup, then the images look way oversaturated (and a touch too dark/contrasty as well). So I can't use Chrome with my monitor in Adobe RGB mode, regardless of the fact that everything online can be assumed to be sRGB.
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  #31  
Old 15-06-2013, 09:05 PM
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Quote:
Originally Posted by philiphart View Post
The problem is that even viewing sRGB images online, if the monitor is set to Adobe RGB but the browser is ignoring the monitor profile in the operating system setup, then the images look way oversaturated (and a touch too dark/contrasty as well). So I can't use my Chrome with my monitor in Adobe RGB mode, even though everything online can be assumed to be sRGB.
I'm not sure how it works in Windows, but honouring or ignoring display device profiles is a system-wide capability. The basic information flow on colour managed systems is: browser downloads tagged image, uses tagged (or embedded) profile data to interpret RGB pixel values and convert them into the system's colour connecting space (typically XIE or Lab), browser hands converted pixel value to GUI/display subsystem, there the display device's colour profile is reverse-applied and the resulting pixel values are sent to the display hardware.

Are you sure your display behaves like Adobe RGB? This may not entirely be up to the monitor, the video card will most likely contain configurable LUTs (lookup tables) to convert pixel values as well. The only way to be sure is to obtain a display profile using a colorimeter. This will cover both monitor and video card behaviour and should give you correct looking images, no matter what colour space the original image file uses.

Cheers
Steffen.
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  #32  
Old 15-06-2013, 09:18 PM
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Originally Posted by Garbz View Post
A far better approach would be to put your monitor into a native setting if it has one and then download the correct colour profile for it. Having wide gamut monitors retard their performance to match the working space of an image defeats the purpose of colour management.

The only profile your monitor should have is the one the manufacturer gave you or the one you've generated through the use of a calibration device.
Thanks.. I do have the option of using a Dell U2410 profile but when I try setting that in the OS color management setup, I don't get the right result in Photoshop. Something to investigate further one day.. I'm happy with the result using the monitor in sRGB or Adobe RGB mode with the corresponding display profile, but I can see what you mean about that defeating the purpose of having colour management and monitor profiles in the first place.
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  #33  
Old 15-06-2013, 09:39 PM
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The display profile must match the settings (calibration) of course, otherwise the results will be hard to predict, but mostly wrong. I rarely trust the vendor supplied profiles unless the display has a menu setting that says "match vendor supplied profile". Then there is is the issue of video card LUTs which are entirely under software control, and which the monitor vendor cannot know about.

Cheers
Steffen.
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  #34  
Old 15-06-2013, 09:53 PM
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Quote:
Originally Posted by Steffen View Post
The display profile must match the settings (calibration) of course, otherwise the results will be hard to predict, but mostly wrong. I rarely trust the vendor supplied profiles unless the display has a menu setting that says "match vendor supplied profile". Then there is is the issue of video card LUTs which are entirely under software control, and which the monitor vendor cannot know about.

Cheers
Steffen.
Yes.. I was thinking along similar lines. The only setting on the monitor that makes sense to use with the Dell profile in the OS is called "Standard" (top of the list in the monitor menu list of preset modes) but it doesn't get the right result. I'm happy that the factory calibration to sRGB and Adobe RGB is done well so will stick with those for the moment and curse the fact that Chrome doesn't care about my monitor profile..
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  #35  
Old 18-06-2013, 10:14 PM
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I'm not sure how it works in Windows, but honouring or ignoring display device profiles is a system-wide capability.
The short answer is it doesn't. In Windows the OS provides an API for colour management only. It's up the to the application to request windows to provide it the current display profile. It's up to the application to convert the profiles or to make a call to WCM to convert the profiles on it's behalf. And then the application hands the data to the video card which faithfully sends the data to the monitor unless the lookup table has something so say about it.

The video card lookup table should universally never be able used for colour space conversion as any deviations from the standard curve cause a loss of quality. It's only used for ensuring that response follows the correct curve without a colour shift throughout the range of tones and actual colour management itself is managed by ... well ... colour management.

In the windows world colour management is one ugly steaming turd.
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