Dunno about you but i'd rather have this than a relume. This is still ok by my standards and i have seen worse. but then again, i'm coming from a collector and purist perspective.
I'd like to keep the original lume, but looking at how fast the lume disintegrates I'm is there a way to preserve the original lume? People told me the binding solution can be reapplied to old lume, like an invisible protective layer.
Its a risky procedure, and it usually works only for lume in good condition but started yellowing.
If your lume as you said is already crumbling, the application of the binder coat will only worsen the situation, i.e the lume may come off during the application process.
IMHO, its better to leave it alone, or opt for a relume with proper pigmentation.
