Trying to narrow down a useful palette

[HarryKn]

My phone keeps making my skin look different in every room, so I am questioning the undertone notes I made from photographs. Near a window, my face appears fairly neutral. Under a ceiling light it looks warmer, while the camera sometimes pushes the whole image toward pink. The background changes too, which seems like a warning sign. I found descriptions of skin tone analysis but I do not know how much faith to put in an automatic phone image. I would stay away from strong shadows. I can turn off beauty filters. I could hold the same white card beside my face and photograph it at roughly the same time on several days. Is it useful to keep camera settings fixed? I could compare images only when the settings match. I would also compare the actual fabric in a mirror, because the photo may be recording the room more than my skin. I am trying to avoid chasing tiny shifts in an image. For people who have done this carefully, which lighting conditions gave consistent observations, and when did you decide a photo was misleading? I can repeat the comparison before drawing a conclusion. A practical checklist would help me separate the camera settings from the colors I am trying to judge.