What are the characteristics of Pentax SLR camera in portrait shooting? Are there any advantages? Will the photos taken by Pentax turn yellow?

You are talking about the characteristics of JPG format. The original machine doesn't have these things, so you have to adjust it yourself.

JPG is straight out, and when the color temperature is correct, Pentax's skin color is basically correct, as are yellow people, but we prefer white and pink.

Canon's in-machine processing, skin color is more pleasing, always like this.

Nikon always feels a little gray. In order to keep more details, it is good to handle it a little. However, Nikon's in-machine processing in the past two years has also been pleasing to the eye.