• 1. Natural light — Shoot near a window in midday daylight, or under near-white light. Yellow incandescent bulbs, blue fluorescent tubes and colored ambient lamps all shift your skin tone.
• 2. Face the camera — Keep your whole face facing forward, with no heavy shadow falling on one side.
• 3. Skip the filters — Turn off brightening and smoothing filters and automatic color correction, and use a photo that is close to the original.
• 4. Go easy on color makeup — Bold lips, blush and colored contacts cover up your natural skin tone.

• - Indoor shots with strong yellow or blue lighting
• - Selfies with filters or editing applied
• - Backlit shots, or shadow covering half your face
• - Photos where a mask or sunglasses hide your face
• - Screenshots, where the color has been shifted one more time

A selfie-based personal color analysis ultimately leans on the color information in a single photo. When the lighting or white balance of that photo changes, the color information in your skin changes with it, so the same person can come out as a different type. Displays also reproduce color differently from one another, which is a built-in limit of any online analysis — so a good input photo is what contributes most to a result you can trust.