The photos taken show that the portrait with red background is blue, the portrait with blue background is yellow, and the white background is basically normal. Why?

Let's talk about why the white background is basically normal.

Photo ID generally uses a photo lamp, and the light of the photo lamp will not have much problem. When it shines on a white background, the light reflected into the camera lens will not change much, which is basically the same as the light reflected from the photo lamp to the human face, so there will be no problem with the white balance.

When a red background and blue are used, the light reflected by the background changes (other colors of light are absorbed and only red and blue are reflected), but the light shining on the face is still white. If automatic white balance is used, the judgment may be based on background light, and finally a portrait will be cast.

The corresponding method is simple. Take a close shot of the face, and after you get the correct data, set the white balance to custom, and use the customized set of data when shooting. But at this time, the background color will be cast. Just slightly modify the background color on the computer.

Actually, this kind of photography in the studio is the most convenient. First of all, make sure the photographer is unbiased. Because the background is solid color, it is very simple to modify it by computer. If it really doesn't work, just remove the whole background and draw it again.

Supplement: By analogy, if you are too troublesome, use a white background for everything, and finally cut out the picture and fill in the color on the computer. Ha ha! I'm so talented.