Post processing preferences

[xpatUSA]

Thanks to everyone. This has been an interesting and useful thread.

It's clear that we filter out much of the blue cast during blue hour, but I don't know how much remains in our perception at the time. I have to read more and experiment more. And I actually can't decide which of these many versions I prefer, except that I don't like the truly neutral one.

For what it's worth, some numbers:

"The light has a color temperature in the blue hour between 9000 and 12000 Kelvin."

From:

https://www.photocourse.info/the-blue-hour.php

The "blue hour" is said to be between -4 and -6 deg. sun elevation (PM) or -6 and -4 deg. (AM).

Adjusting by equal amounts of deg.K may not work well, it appears to be quite non-linear if you look at the CIELUV graph.

[DanK]

For what it's worth, some numbers:

"The light has a color temperature in the blue hour between 9000 and 12000 Kelvin."

From:

https://www.photocourse.info/the-blue-hour.php

The "blue hour" is said to be between -4 and -6 deg. sun elevation (PM) or -6 and -4 deg. (AM).

Adjusting by equal amounts of deg.K may not work well, it appears to be quite non-linear if you look at the CIELUV graph.

The night photographer who is arguing for a neutral rendition sent me an image that he took at a setting of 10,000 K that still had a blue cast, which supports the conclusion that the color can be yet more extreme.

I think he has one valid argument for an adjustment in camera, even if it is approximate. That is, the in-camera JPEG thumbnail and the RGB histograms are based on that setting. He has had cases in which the histogram showed no clipping but there was in fact clipping because the WB was so far off. So, his argument would be that it would be better to set the camera for some value in that range, say 9000 K, than to leave it on AWB or a lower fixed value.

[xpatUSA]

The night photographer who is arguing for a neutral rendition sent me an image that he took at a setting of 10,000 K that still had a blue cast, which supports the conclusion that the color can be yet more extreme.

I think he has one valid argument for an adjustment in camera, even if it is approximate. That is, the in-camera JPEG thumbnail and the RGB histograms are based on that setting. He has had cases in which the histogram showed no clipping but there was in fact clipping because the WB was so far off. So, his argument would be that it would be better to set the camera for some value in that range, say 9000 K, than to leave it on AWB or a lower fixed value.

Interesting - assuming that he is not shooting raw because, as you know, the WB setting does not affect raw data from most cameras but, as you said, it does affect the rendering on the LCD and the histogram. A situation not unlike the dreaded 'exposure triangle' where the histogram can show "clipping" while the sensor can be horribly under-exposed.

I just looked at my GH1 instruction book and deg.K in Manual WB is adjustable up to 10,000K max with slight further adjustments possible in 4 directions of tint.

[Manfred M]

So, his argument would be that it would be better to set the camera for some value in that range, say 9000 K, than to leave it on AWB or a lower fixed value.

I'm not sure what your camera does Dan, but my AWB is limited to the range of 3500K - 8000K I can manually select values from 2500K - 10000K, if I so desire.

I really do find that some of these scenes are impossible to white balance, but then often we wouldn't want to because we either want the warm tones of golden hour and sunset or the cool blue tones of blue hour.

This shot is taken when I was standing on the city wall of Quebec City during the second week of July. Civil twilight ended at 21:18 and this shot was taken at 21:12; so well into "blue hour". The blue in the sky (actually more cyan than blue) and the yellow from the street lamps do not allow for a single white balance value for this image. If I correct for the sky, the lights in the city will become even more orange, If I correct to the street lighting I get blue pretty well everywhere.

Most blue hour shots, unless taken out where there is no artificial light, tend to be mixed light shots.

[odds]

In the world of color there is a property called the "just noticeable difference"

I guess that is where the Mired unit may come in handy: https://en.wikipedia.org/wiki/Mired

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Odd S.