Question on Color-Checking Photo Subjects

[Michael Erlewine]

Since winter is still hanging on, I’m mostly relegated to my small studio in my home. Something I mean to do, but often forget at the end of a long stack is to take a photo of the color-checker card. Why? Because, it is a PITA, because I have to somehow position the color-checker card with one hand and also focus and take the photo with the other.

So, I took one of our microphone stands, put a 19” flexible gooseneck on the stand with a clamp on the top end, and put the color-checker in the clamp. Now, all I have to do is bend the gooseneck into the frame of the photo and take a snapshot. My question is, should I place the color-checker card in front of the flowers, in the middle of the flowers, or behind the flowers to get the best reading.

Sorry about the poor quality of this snapshot.

[charlie]

If you were to place it in or behind the flowers it is possible that some of the color of the flowers might reflect on to the color checker and give you a false reading. You want to balance the color based on the light, not the subject.

When using the color checker for shooting models, product, or artwork it always goes in front of them so I don't see why your setup would be any different. Just so long as the same light source(s) that are lighting your subject are lighting the color checker you should be fine. And remember not to touch the color squares with anything that might stain them as things like the oil from your skin can influence the color reading/white balance.

[Frank Fremerey]

Charlie is right. You measure the light color on the subject. Wear a high visibility vest while doing so and the light character will be changed. So care that no reflections change the light character.

In your frame the clamp covers one of the probes.

[Michael Erlewine]

Charlie is right. You measure the light color on the subject. Wear a high visibility vest while doing so and the light character will be changed. So care that no reflections change the light character.

In your frame the clamp covers one of the probes.

That's what I thought. Thanks everyone for the info. I know that clamp is not where it should be. Just a quick shot. I will better clamp it, of course.

[Alaun]

And as far as I recall, you do not need a focused picture of the color patches ;-)

[Bjørn Rørslett]

Correct, if the aim is to make a session profile in Phjoto Ninja for example, all that is required is having an even light onto the card and no overlap or blur into the neighbouring patches. Perfect sharpness is not required and even may be counterproductive, as small dust spots can interfere with the reading of the patches.

The advice of treating the card with care and try to avoid touching or worse, scratching, the surface is  very relevant. Try shooting such a card in UV, the spectral range of which will emphasise surface defects, and most cards will rapidly show an amazing amount of flaws and artifacts from its handling ...