Profiled monitor - Is photoshop using it?

[Spooky]

I have an LCD and CRT monitor. I do my photoshop work on my CRT. I have calibrated my monitors and profiled them. I then downloaded the windows colour applet from the microsoft site and assigned the relevant profile to each monitor.

When I open photoshop and go to edit/color settings and look at the Working space RGB field I have Adoebe RBG (1998) listed. When I scroll through the options in this field beside Monitor RGB - is listed my LCD monitor profile not my CRT profile which is the monitor I use for editing.

Is this a problem or can photoshop only show the primary monitor profile here in this box but it still applies the correct profile for my CRT monitor even though it doesn't show it in the colour settings box.

Thanks

[big pix]

Bret........ this will give you a lot of info on profiles......

http://www.imagescience.com.au/index.html

[Spooky]

Seems a bit commerical now that site. Don't think they are giving away much info but are trying to make a dollar from selling stuff. Not that I blame them.

[shakey]

Intriguing question. I only have a single monitor system so I'm just speculating. It would appear that the user cannot set the monitor RGB in PS. In a single monitor system it doesn't matter...photoshop just chooses the current monitor profile. In a dual monitor system PS doesn't "know" which monitor, and therefore which profile, is the critical colour displayer. It "may" just choose the most recent profile, so why not try just calibrating the CRT, reboot, and see whether the new profile shows up as the monitor RGB profile. If it does then problem solved....always calibrate the CRT after the LCD. If that doesn't work then the only other thing I can suggest at the moment is to calibrate the CRT and assign that profile to both the CRT and the LCD...that is of course assuming that the LCD is not really being used for colour managed tasks. This may be complete BS, but interested to know whether you try this, since I would like to go the dual monitor approach myself in the near future.

[jdear]

dunno if this is helpful, but when I calibrated my monitor, I needed to remove adobe gamma from the startup folder on the computer so it did use the monitor profile instead... not sure if this affects PS though...

J

[Spooky]

I did calibrate the CRT second. I think maybe it shows the LCD because it is the primary monitor in Windows.

Yes I have removed Adobe Gamma from the startup menu.

Come on, must be some calibrated dual monitor gurus out there using photoshop!

[DaveB]

My own system is a dual-monitor Mac, and I can tell you that Photoshop doesn't _really_ have a concept of "Monitor RGB". The profile of the primary monitor does appear under this name in some of the menus, but that's not something you'd use very often.
By the way, you'd be very unlikely to be in a situation where you wanted it as the default RGB work space!

Photoshop knows what profile/workspace each document is in, and converts that on the fly to the monitor's profile for display. When you drag a window across two monitors, separate conversions are done for each monitor. Actually on my own machine the conversion is updated when you release the window (e.g. drag a window across and you'll see the colours on the new display be "off" slightly, and get corrected when you release the window).
I'll check this on a dual-monitor XP machine later today.

Don't worry about Photoshop handling the separate profiles: it does. What you should be concerned about is whether your graphics card and the Windows drivers for it will load a separate LUT (R/G/B look-up-table) for each monitor: you typically need two graphics cards (or one that appears to the OS to be two cards even if it's physically not) for this to work with XP. Without that you're stuck with trying to get the calibration of each monitor to be as close as possible (obviously easier if they're the same model) and accepting that the colours on the secondary monitor might not be perfect.

Does that answer your question?

By the way, in today's updates to my website you will find the profiling services I offer...

[Dougie]

I am running XP with a single card and am able to have two different monitor profiles. I have to change the profile of the second monitor on start up, but works absolutely fine. The profile chooser software that came with my spyder is all I use. Apart from that I agree with all DaveB's other comments
Doug

[DaveB]

Doug, note that I didn't say that you can't have separate profiles for each monitor on a dual-head card, just that with many cards it doesn't work properly under Windows. Working "properly" in this context means that not only does Windows think there's a separate profile for each display, but also that the correct colours are displayed on the screens...

The LUT (LookUp Table - a set of 3 maps for R/G/B that's applied to the data out of the graphics chip just before it gets sent to the monitor [e.g. turned into an analog voltage for VGA, or sent across the DVI cable]) is the partner of the profile. It contains part of the calibration of the monitor, and does things like ensuring that greys remain neutral for non-colour-managed graphics. It's stored within the ICC profile by the profiling software, and is loaded into the graphics card when you select the profile. Most software such as Photoshop that deals with the profile doesn't have to know anything about it.

Unfortunately I think the XP driver interface only lets you load the LUT for a card, not per-monitor. Thus if your dual-head card appears to XP as a single device with two monitors, only one of the LUTs will get loaded, but it will get used for both monitors. Sometimes the effect of this is subtle, but sometimes it's annoyingly noticeable (of course, we each may have different thresholds of annoyance ).
If however your card appears to XP as two separate devices, each with its own monitor then you're probably OK. Have a look under the Device Manager via "View by connection".

[Spooky]

Dave

Thanks for taking the time to replying and sharing your obviously extensive knowledge on the topic.

It appears my card, a Radeon X800 GTO, is recognised by windows XP as two cards and can therefore load the LUT for both monitor outputs. When I look in device manager (view devices by type) under display adapters it shows "Radeon X800 GTO" on one line and the next line shows "Radeon X800 GTO Secondary".

If I am correct with the above point then am I correct in thinking based on your advice that my system is setup correctly and photoshop will adjust for each montior correctly and I don't have to do anything further?

Thanks

[DaveB]

It appears my card, a Radeon X800 GTO, is recognised by windows XP as two cards and can therefore load the LUT for both monitor outputs. When I look in device manager (view devices by type) under display adapters it shows "Radeon X800 GTO" on one line and the next line shows "Radeon X800 GTO Secondary".

If I am correct with the above point then am I correct in thinking based on your advice that my system is setup correctly and photoshop will adjust for each montior correctly and I don't have to do anything further?

Yes I would assume that you're OK.

But you can test it:

1. Make copies of the profiles for each monitor.
2. Use profile-editing software to tweak the LUTs in each one. Many monitor-calibration softwares will let you edit the curves (they present the LUTs as R/G/B graphs).
   Sometimes it only lets you make this modification in the last step of generating a new profile, but some software will let you tweak existing profiles.
3. Change one so red and blue are zero, and change the other so green and blue are zero.
4. Load up the modified profiles as if they were "correct".
5. Hopefully one of your monitors will look green, and the other one will look red. But if they're both the same colour then you know that both LUTs have been set the same.
6. Don't forget to re-load the original profiles!