How do you separate close seasonal palettes?

I would like to take undertone photos without letting my phone decide the colours. I have noticed that automatic settings can hide the differences I am looking for. I plan to use indirect daylight near one window rather than direct sun. I will keep the same camera distance and avoid filters, portrait mode, and flash. A small grey reference seems more dependable than judging one image in isolation. My goal is to retake the same photos on a second day for comparison. A [url=https://color-type.top]skin undertone test camera[/url] might be a useful checklist before I compare the photographs side by side. I am treating the photos as notes, not as a definitive diagnosis. Looking at matched photos together should reveal whether the change is actually consistent. How do you keep your phone from changing the comparison halfway through? I would prefer a routine that works with ordinary household materials. Keeping the original files feels important when automatic processing can be so persuasive. Thanks for any practical suggestions from your own experiments.