Permanent Way to Darken or "Ebonize" a Rosewood Fretboard?

[Wattage]

Rarely have I had anything mess up the inlays but I guess if you leave anything on long enough it could stain

I usually use a stain and then once that has dried I'll seal the board with watco oil

Works better than most things I have tried but I'd recommend trying it on a scrap piece of wood to see how it works for you. Also clean the board before you apply anything, that'll help it retain the color

Rosewood is an oil-y wood and doesn't really take stain all that well

 

[Aceman]

But it's pretty tuff to mask off inlays. (Actually it's impossible).

Just use inlay decals. The little red/blue/green etc pearlescent stickers. Perfect mask for dots.

 

[solspirit]

Montypresso works well on actual rosewood, darkens it several shades - and you can do repeat applications if desired.
It's been hit-or-miss for me on pau ferro, perhaps depending on the tightness of the grain and how it was treated in the factory.
Worked nicely for me on one pau ferro board but hardly did anything on another.

Stew-Mac also sells a fretboard darkening oil - not the dye for ebonizing, a separate product for darkening.
You can make your own using ith a light grade of mineral oil ('white oil' or lamp oil) and some artist's oil paint.
.

Espresso isn't bad either. . . .
it really 'amps' up your fretwork.

 

[GuitarDoc]

Just use inlay decals. The little red/blue/green etc pearlescent stickers. Perfect mask for dots.

That's not a bad idea. Didn't think of that.