AFJuvat,

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Interesting discussion, I wonder if Haematoxylin stains, used by histology for specimen slide staining, would work?

I guess I'll have to talk with our Pathology folks and see if I can acquire some.

Otherwise, I just use Birchwood Casey's walnut stain and apply till I reach the shade desired.  Not always fool proof but it applies well and is very forgiving.

Maybe I'm not a purist but I do get the results that appeal to my taste while trying to stay true to the original look.