How do I stop our trim-plate lessons mixing two surface finishes?

Check the parts, not just their bags.

Parts checked. Both finishes belong to this job. Quality supplied separate accepted and scratched references for each.

Does one camera arrangement need to handle both finishes? Or will the setup change when the finish changes? That choice belongs in the trial, not in an explanation added after the difficult images appear.

One arrangement is proposed. Vision engineer has both finish sets for the same repeated-presentation comparison.

Include the inspected edges. Don't let a convenient crop remove the real scratch.

David Baker's point is worth checking against the actual acceptance area. You can make two finishes look similar by excluding exactly the surface quality needs inspected.

Full required area stays in. First lighting candidate hides an edge scratch on one finish. Rejected that candidate.

Useful to keep that failed comparison with the lesson. People see a clean image and understandably assume the inspection improved. Here it got cleaner by losing something it needed to show.

Has the next candidate handled both reference sets, Ravi, or is the shared arrangement still an open question?