8mm home movies, if the amateur cameraman wasn't careful with his settings, can have the problem of exposure varying widely from scene to scene. And even though varying the frame-to-frame exposure during scanning is undesirable, I can see that there might be benefits in altering the exposure scene-to-scene.
Are any high-end scanners capable of doing a 2-pass scan? i.e. the first 'preview' pass works out where the scene changes are and calculates exposure; then during the second pass, the exposure is altered to boost dark scenes, or reduce bright scenes.
Some providers offer a manual version of the above – a "best light" service whereby they go through the footage scene-by-scene and balance out any inconsistencies in the lighting, whether under or over-exposed.
Could such a 2-pass scheme have unintended consequences?