What raking light changes

Ambient light gives a useful neutral view of a card. It is less reliable for shallow scratches, pressure marks and changes in gloss because the light reaches the surface from many directions. Raking light arrives at a low angle. Small changes in the surface interrupt that light and become easier to locate.

That does not make every bright line a defect. Texture, print finish, dust and the lighting itself can create highlights. This is why Best Grading Tools combines ambient and raking-light frames instead of treating one image as definitive.

A repeatable capture

Place the unsleeved card on a dark matte background. Keep it within the on-screen guide and tilt slowly rather than moving the phone quickly. The capture sequence chooses two complementary frames for each phase, rectifies perspective locally and discards the temporary video.

The final report should only describe evidence that can be traced back to those selected frames. If the card is sleeved, blurred or dominated by glare, a responsible result is a recapture—not an invented grade.

Separating glare from persistent evidence

A reflection usually moves or changes shape when the card angle changes. A real surface change remains in the same area even when its contrast becomes stronger or weaker. This is why the sequence does not choose two identical images: it looks for complementary views that make position, outline and intensity easier to compare.

Do not decide from one bright frame. Check whether the signal is also supported under ambient light, appears from another angle and can be located against an edge or printed detail. A clipped highlight with no remaining texture does not prove a defect. The guide to corners, edges, surface and centering explains how to keep those categories separate before reading the grade.

What the report can and cannot say

A BGT report is a visual condition estimate. It can organize visible evidence, apply a conservative rubric and make repeat captures easier to compare. It cannot certify authenticity, guarantee another company’s grade or replace an in-person inspection.