MAILWIFE

I've been trying to work out my undertone from phone photos, but the answer seems to change with the room. With my bedroom lights on, my skin appears yellow; near a window it looks much cooler. I would like a method I can repeat instead of trusting one flattering photo. My next step may be pictures beside an open window, with the same camera and no beauty filter. That should at least keep the lighting more consistent. Does putting a plain white card in the frame help spot white balance shifts? I don't know if bare skin is more useful than the foundation I usually wear. For a separate appearance check, I found color analysis and thought it might help me frame the comparison without treating a screen result as proof. I would rather compare several signs than decide from a single selfie. If you have done this at home, what lighting and camera settings worked for you? I could hold different colored clothes near my face to see what changes. I can repeat the check a week later to see whether the impression holds. I'd appreciate practical steps, especially ways to catch a misleading camera result before buying anything based on it.