How to unify the tone of color background photos? Is it the effect of direct shooting or PS post-processing?

I just took it. If I guess correctly, I was in my room and didn't use the flash. If only scattered light is used to illuminate the glasses, there will be no reflection and the color of the background will be very uniform. If it is adjusted, it will be a little different.

The most important thing is that when a unit or school takes a photo of a certificate, most of them only require the five senses to be correct and clear. As for whether it looks good or not, no one goes back to care, and ps is just a formality.

As for how to make the background uniform, it is too simple. A blue or red background cloth is hung on the wall, and a stool is placed in front. Everyone is sitting on that stool, because everyone has the same background, so the colors are naturally unified. Even if some people are different, it is difficult to tell them apart.