darkening a rosewood fretboard?

axisus

Is there any way it can be done? 

TheMarlin

Leather dye. Done it to one of mine with fantastic results. Rub down with wire wool between coats.  At least 3 coats. Markers may change colour. 

Zoolooter

Just used this for the very same. Used 3 coats then a couple of coats of tung oil. First coat of tung oil thinned with spirit.

https://m.ebay.co.uk/sch/i.html?_odkw=dark+brown+oil+stain&_from=R40&_trksid=m4084.l1313&_nkw=dark+brown+oil+stain

WezV

Fiebings do dark brown and black leather dye.  How dark do you want?

do it on raw wood for best results

PVO_Dave

Following some advice on here, I used a Miniwax ebony pen, came out well: 

http://www.thefretboard.co.uk/discussion/comment/1142539/#Comment_1142539 

rze99

Have also used Punch leather dye and tung oil wire wool method very effective. I found combing a bit of black with dark brown gives best result. some coan come off over time and may need reapplication in high were areas. Also dark wood colour restoration is good for maintaining the look and lustre.