Ambient light White point suggestion

[namefaceguy]

Hi there Florian.

I’ve been slowly learning more and more about this great software of yours but I’ve recently found an idea that could be useful for some people.  Would it be possible to couple the ambient light reading with a white point suggestion?  Obviously enforcing an arbitrary white point is not usually what you would want but what if the ambient reading gave a suggestion for a white point that would be appropriate with the new high gamma?  I’ve been digging around for advice and found that for my very dark room my 1200:1 a higher gamma of 2.5 is necessary for low light levels around 80 cd/m.  I then discovered that the standard for projection in a completely dark room is 2.6 gamma at 48 cd/m .   It might be possible to couple the ambient light reading with a more complete gamma and  white point level suggestion.   Coupling this with the 120 cd/m recommendation at 2.4 (or 2.2 for higher brightness) I believe  this could help make the ambient light information more useful for more people.

Would this be feasible and or a good thing?

Thank you once again for your incredible work.

• This topic was modified 5 years, 9 months ago by namefaceguy.

[Florian Höch]

Hi,

setting the white point based on an ambient light reading is already possible (click the respective icon next to the whitepoint setting).

[namefaceguy]

Hi,

Currently when I click the icon it brings up window on the screen to measure the current whitepoint but it does not let me use my i1 display to collect ambient data and use that to help select the proper white point.

[Florian Höch]

Are you sure you have used the “measure ambient” button (crosshairs next to whitepoint) and not the visual whitepoint editor? The former is what you want in this case.

[namefaceguy]

Yes I am sure.   When I click the target a white screen with measure appears on it and tells me that my sensor is in the wrong position when I click it.     I don’t see the point of measuring the white point with this when I have interactive display adjustment enabled.  If this isn’t what you intended it may be a bug or a remnant from a previous version.  I’m using the latest version.  Hope this helps unless I’m missing something.

[Florian Höch]

As I said, you’re clicking the wrong button.

[namefaceguy]

My apologies I meant white level this whole time.  Sorry for the confusion.  Would this be possible to suggest white level using ambient reading?

• This reply was modified 5 years, 9 months ago by namefaceguy.

[Florian Höch]

Ah, now I understand. Yes, I’ll add that with the next update. Until then, you can use the lux value from the ambient reading if it’s above 40.

[namefaceguy]

Thanks a million.
I’ve deduced that the correct way to measure is from the viewing position.  Take measurements of white level on screen then from the same position the wall behind the screen and try to balance the lux I gather  since that’s would be the light that my eyes would receive. The current white level  measurement screen can be useful to capture the white from the screen but would require a promp after recording the white level on screen to then record the light behind the screen.  This could actually be really helpful in answering the  common question “how bright should my screen be?”  I’ve just done some tests and this works really well.

Thanks once again

[Florian Höch]

This could actually be really helpful in answering the common question “how bright should my screen be?”

The answer to that question is “roughly the same as the ambient illumination”, as this causes the least eye strain. There is a lower limit though (around 40 cd/m2 in a dark room) if small luminance differences (gradations) should still be discernible (e.g. see Mantiuk et al, “Display Considerations for Night and Low-Illumination Viewing”). To determine a suitable luminance target based on ambient light conditions, ambient light levels should be measured with the instrument sitting next (not in front) of the display, diffuser facing upwards.

[namefaceguy]

Is this still applicable if you have led lights directly behind the monitor as your main light source?  I have a white wall  illuminated by the led lights and a dark blue ceiling and I feel the measurements aren’t really accurate using this method with my current set up.   Barely any light is measured while the light behind the monitor is much brighter.  Maybe I should calculate a compromise between the two data points?

[Florian Höch]

dark blue ceiling

Hmm, that’s not ideal. Ideally walls etc. should be spectrally flat (there’s gray paints available with that property) or at least not colored.

Maybe I should calculate a compromise between the two data points?

Trust your eyes on this. Adjust the monitor to a comfortable white level during interactive adjustment (don’t set a target) and stick with that.

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