Display colorsync profile remains unapplied?

[Christopher Hunt]

On 21/03/2007, at 3:25 PM, Chris Murphy wrote:

> Depending on the machine you're using and OS version, it may look  
> like you can separately set different profiles to two displays but  
> in reality you can't. So one of them might not be used.
>
> But it's more likely the two displays behave differently. Are they  
> connected to the same video card, or two different cards?
Same video card using the two DVI ports.

>
>> I'll also add that the brighter display is not just brighter, but  
>> the blues are richer etc. so there does appear to be colour  
>> differences. It may well be that the differences are associated  
>> with a newer bulb in the brighter projector but when I saw it  
>> yesterday it did look like a Colorsync difference.
>
> Well chances are it isn't a ColorSync difference, because most  
> applications are stupid when it comes to color management. Most  
> applications simply use the display profile as the source profile  
> and then Quartz uses the display profile as destination. When  
> source = destination, there is no transformation, so ColorSync  
> isn't even doing anything. That would mean the displays are just  
> different. But to know for sure, we'd need more information.  
> Machine, video cards, OS version, what application (and if it's  
> obscure does it tell the OS what the source color space is  
> correctly or not), etc.
It is my application which is heavily OpenGL based using Cocoa as a  
shell (NSOpenGLView). No specific colour profile management going on  
within the app.

I have witnessed that changing the colour profile changes the screen  
appearance on past visits to the machine.

Here is the (hopefully relevant) system info.

Hardware:

     Hardware Overview:

       Machine Name: Mac Pro
       Machine Model: MacPro1,1
       Processor Name: Dual-Core Intel Xeon
       Processor Speed: 2 GHz
       Number Of Processors: 2
       Total Number Of Cores: 4
       L2 Cache (per processor): 4 MB
       Memory: 1 GB
       Bus Speed: 1.33 GHz
       Boot ROM Version: MP11.005C.B04
       SMC Version: 1.7f8
       Serial Number: YM703087UPZ

Software:

     System Software Overview:

       System Version: Mac OS X 10.4.8 (8N1250)
       Kernel Version: Darwin 8.8.4

Graphics/Displays:

     NVIDIA GeForce 7300 GT:

       Chipset Model: NVIDIA GeForce 7300 GT
       Type: Display
       Bus: PCIe
       Slot: Slot-4
       VRAM (Total): 256 MB
       Vendor: NVIDIA (0x10de)
       Device ID: 0x0393
       Revision ID: 0x00a1
       ROM Revision: 3008
       Displays:
         Display:
         Display:

     NVIDIA GeForce 7300 GT:

       Chipset Model: NVIDIA GeForce 7300 GT
       Type: Display
       Bus: PCIe
       Slot: Slot-1
       VRAM (Total): 256 MB
       Vendor: NVIDIA (0x10de)
       Device ID: 0x0393
       Revision ID: 0x00a1
       ROM Revision: 3008
       Displays:
         Display:
         Display:

PCI Cards:

     NVIDIA GeForce 7300 GT:

       Name: NVDA,Display-B
       Type: display
       Bus: PCI
       Slot: Slot-4
       Vendor ID: 0x10de
       Device ID: 0x0393
       Subsystem Vendor ID: 0x0000
       Subsystem ID: 0x0010
       ROM Revision: 3008
       Revision ID: 0x00a1

     NVIDIA GeForce 7300 GT:

       Name: NVDA,Display-B
       Type: display
       Bus: PCI
       Slot: Slot-1
       Vendor ID: 0x10de
       Device ID: 0x0393
       Subsystem Vendor ID: 0x0000
       Subsystem ID: 0x0010
       ROM Revision: 3008
       Revision ID: 0x00a1

Thanks for your attention to this.

Cheers,
-C