For interest plus Argyll colour management / DispCalGui info. I had a lot of problems shooting for 6500K as the blue jumped suddenly near the correct RGB balance. While messing around I found that the monitor brightness adjustment made very little difference to the balance so went back to the initial RGB setting suggested by tftcentral uk and ran a calibration it was ok but came out at 7000K with my video card and monitor so I started using as read for white balance and luminance levels and in the case reducing blue by 2 gave a perfect balance at what turned out to be 6600K.

The blue jumping is probably down to Dell providing a 0-100 adjustment range when hardware probably uses 0-255, rounding errors in other word. Stupid really because if the factory menu is bought up they clearly use native values which it seems we can't cope with.

The other problem I had relates to my previous monitor. When I looked at the tone curves the calibration produced there were clearly errors in RGB at low luminance levels so I activated the bottom black point compensation option which went a long way to cleaning it up. So I set that by default this time and also played with and without the auto option and it's rate. Results were good but just out of curiosity I ran one with both off and the results particularly at the bottom end of the grey scale were even better. Looks like using these when not needed can make things worse. The auto/rate one also reduces dynamic range. The best option seems to be to leave this off and only use them if the tone curves show significant errors.

This is the calibration measurement report. Never know it might stop Colin and Robin wondering about my monitor. I'll be posting warm images next.
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Dell U2713HM calibration

John
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