Only one camera profile for outdoors?

[texshooter]

I am told only one camera color profile is needed when shooting outdoors under natural light because the sun has the same light spectrum regardless of its color temprature.  Is this really true? Or does practice differ from theory with regards to extreme outdoor conditions, such as moonlight, underwater, forests, and especially blue twilight when the sun has dipped completely over the horizon? Is white balancing all I need, or should I build a ColorChecker profile for these mentioned lighting conditions, whether shooting portraits or not?

[digitaldog]

I am told only one camera color profile is needed when shooting outdoors under natural light because the sun has the same light spectrum regardless of its color temprature.  Is this really true?

True. Illustrated here:

In this 30 minute video, we’ll look into the creation and use of DNG camera profiles in three raw converters. The video covers:

What are DNG camera profiles, how do they differ from ICC camera profiles.
Misconceptions about DNG camera profiles.
Just when, and why do you need to build custom DNG camera profiles?
How to build custom DNG camera profiles using the X-rite Passport software.
The role of various illuminants on camera sensors and DNG camera profiles.
Dual Illuminant DNG camera profiles.
Examples of usage of DNG camera profiles in Lightroom, ACR, and Iridient Developer.

Low Rez (YouTube):
http://youtu.be/_fikTm8XIt4

High Rez (download):
http://www.digitaldog.net/files/DNG%20Camera%20profile%20video.mov

White Balance is a separate issue, process. It is still necessary and useful depending on the current rendering you see and if you wish to alter it.

[torger]

I am told only one camera color profile is needed when shooting outdoors under natural light because the sun has the same light spectrum regardless of its color temprature.  Is this really true? Or does practice differ from theory with regards to extreme outdoor conditions, such as moonlight, underwater, forests, and especially blue twilight when the sun has dipped completely over the horizon? Is white balancing all I need, or should I build a ColorChecker profile for these mentioned lighting conditions, whether shooting portraits or not?

In "extreme" conditions when the sun is not really visible but you have some sort of air light the spectrum is more filtered and different as far as I know, I haven't really found any good source of information though regarding these spectrums though. A problem with these conditions is also that the eye-brain does not register colors in the same way. If you shoot a colorchecker and make a profile the profile will try to make colors look the same way as in daylight, and that is not how the eye-brain see the colors in that situation.

There is no good "foolproof" workflow handling these situations though, so what people do is to use that daylight profile and manually adjust the white balance until it looks good/natural, this usually works well except for some situations with for example mixed sunlight and air light which can require dual white balances to look fully natural.

These challenges are most obvious to me when I'm shooting snowy landscapes in dusk or dawn.

[texshooter]

True. Illustrated here:

Your video does not mention flash.

[digitaldog]

Your video does not mention flash.

No difference. It's an illuminant.

[GWGill]

I am told only one camera color profile is needed when shooting outdoors under natural light because the sun has the same light spectrum regardless of its color temprature.

This is not true - if the spectra were the same, then the color temperature would be the same.

It is true that they are similarly composed, perhaps supporting the idea that a single profile will cover a range of out door conditions.

[digitaldog]

According to Eric Chan:
To to answer the question of WB and it's relevance to building & using DNG profiles: in principle, the applicability of a profile with a given WB has to do with how close the spectrum of the scene illuminant (used to photograph your real image) is to the spectrum of the illuminant used to build the profile. The closer they are, the better the results. Many flavors of natural daylight are spectrally similar (weighted differently), so this is why a daylight profile tends to work well in many flavors of daylight regardless of the actual CCT (e.g., 4700 K thru 7500 K). So even if you built your own profile under real daylight that ended up being around 6200 K, you should not hesitate to use such a profile under other similar daylight conditions, even if the CCT values vary a lot. But if you end up using a very different type of light (e.g., a fluorescent tube) then you should effect quite different, possibly unpleasant results, even if the CCT measures the same (e.g., a 6000 K office fluorescent tube).

The results of the same DNG profile on different spectra and color temperature prove the point.

[ErikKaffehr]

Hi,

I guess that you can use the same profile as long as it is close to daylight. DNG allows for dual illuminant profiles and interpolates between the two illuminants. I would guess this works for continuous spectra, as long as RGB channels are balanced for correct white balance.

For spiky spectra you need an individual profiles. Fluorescent light is spiky.

I have not seen spectral plots of electronic flash, but I understand if the discharge current is high enough it will be similar to blackbody radiation.

Capture one has profiles for "outdoors" and "studio flash" for my P45+, but those profiles seem to be practically identical, give identitical conversion on an IT-8 test chart.

I would also argue that a properly made profile is in all probability better than an adhoc profile made under specific conditions.

Best regards
Erik

According to Eric Chan:
To to answer the question of WB and it's relevance to building & using DNG profiles: in principle, the applicability of a profile with a given WB has to do with how close the spectrum of the scene illuminant (used to photograph your real image) is to the spectrum of the illuminant used to build the profile. The closer they are, the better the results. Many flavors of natural daylight are spectrally similar (weighted differently), so this is why a daylight profile tends to work well in many flavors of daylight regardless of the actual CCT (e.g., 4700 K thru 7500 K). So even if you built your own profile under real daylight that ended up being around 6200 K, you should not hesitate to use such a profile under other similar daylight conditions, even if the CCT values vary a lot. But if you end up using a very different type of light (e.g., a fluorescent tube) then you should effect quite different, possibly unpleasant results, even if the CCT measures the same (e.g., a 6000 K office fluorescent tube).

The results of the same DNG profile on different spectra and color temperature prove the point.