Adobe RGB Colorspace

[annm31428829]

How does Photoshop interact with a graphics card to produce Adobe RGB colorspace?  Assuming the monitor in use is capable of 100% Adobe RGB, is the graphics card or photoshop responsible for accurately generating that colorspace to the monitor?

[davescm]

The key is the monitor profile installed in the operating system. That is either a generic profile from your PC/monitor supplier or, better, created with a calibration & profiling hardware tool. That profile describes what actual colours will be produced when the monitor is sent the digital numbers for each pixel.

The Photoshop colour management system uses the monitor profile, as well as the profile of the image document and translates the digital numbers for each pixel in the image, so that the colours in the document are output correctly by the monitor. All this happens in the background without you having to do anything. For it to work correctly all that is required is :

a. A monitor profile which describes the output of your monitor in its current state, is installed in the operating system. That is why a profile created by a hardware measuring device is better than a generic profile. Any adjustment of monitor controls such as brightness/contrast invalidate the profile as it no longer describes the actual state.

b. A document colour profile embedded in the image document. That is why a profile should always be embedded when saving or exporting a file.

There is no need to set a monitor to the Adobe RGB space, in fact there is an advantage in having the monitor profiled to display the full range of colours of which it is capable. The colours in the document will still be translated correctly, provided the profile describes the actual monitor.

Dave

[annm31428829]

Dave, thank you for your prompt response.

I have always had a hardware and software monitor profiling device in
use in my workflow.

Can you explain in a bit more detail what you mean about saving a
document color profile inside my image document?

Ann

[davescm]

Hi,

When you work inside Photoshop, the software uses the profile that is saved within the document itself. That tells Photoshop whether the RGB (orCMYK) numbers represent the colours in, for example, sRGB, Adobe RGB, ProPhoto ...etc.  When you start a new document, by default, the colour profile set in colour settings is used (unless you choose another in the 'New Document' dialogue.  If you open an existing document , then the colour profile embedded in that document is used.
Where problems can occur, is when a document does not have an embedded profile. Then the numbers could mean anything. So for best practice:

When you save an image, or export it, just check that the tickbox next to the colour profile is checked (it should be by default), in export it is labelled 'Embed Color Profile'.

In Photoshop colour settings, look under Colour management policies and ensure all three are set to 'Preserve Embedded Profiles'. That way on opening, the profile of the document being opened will be used.

With those settings - it should all just work 🙂

Dave

[annm31428829]

Dave, good news...........I am doing this. However, I am very glad you
reminded me to make sure the 'preserve embedded profile' is checked as I
have assumed it would default to that.

Thanks once again.

Ann

[NB, colourmanagement net]

@annm31428829 checking  "preserve embedded profiles" in color settings  is pretty vital - when saving an image - if you see a checkbox to 'embed profile' it should automatically be checked, if it's not, then do make sure you check it. 

Bottom left in Photoshop is an info window with a row of text, you can set that to "document profile" which is pretty useful 

I hope this helps
neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management
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