Profiling -> Double Compensation?

[galvaros]

Dear all,

please excuse my ignorance if the answer to my question is abvious unfortunately, i haven't yet understood the following on a conceptual level:

after profiling the display, the profile tells how to compensate for the display's "error" such that i see how a pixel really looks like. so far so good.

Now, however: e.g. photoshop looks at the profile and compensates the display of the image. This alone would be ok. BUT, the profiling tool (hardware/software) also changes the LUT (look-up table) of the graphics card to compensate for the display's "error".

doesn't this lead to double compensation?

[TommyO]

No, it does not lead to double compensation.

Think of it this way. The monitor calibration now allows the monitor to display the correct color when presented with a standard color value, independent of a viewing colorspace.

Photoshop does not try to do this. Photoshop simply ensures that a color someone creates in one colorspace, i.e. ProPhotoRGB, is translated correctly when viewed in another colorspace, i.e. AdobeRGB.

All applications eventually must send color values to the monitor. This is handled outside of Photoshop, by the operating systems color management system (CMS). So, normally, no double conversions occur. Once in a while, you can have that happen, usually when printing. However, many times it results in what we call a "null" conversion, i.e. converting twice to the same color space does not change the RGB values, it's just wasted cpu time.