In
NetHack, magic markers can also be used to write
spellbooks when applied to
blank spellbooks.
Probability of success is significantly higher if the
spell is known and if the user is a
wizard. A magic marker is a popular item to
wish for with a
wand of wishing or random wishes granted from
thrones,
fountains, etc.
To blank a scroll or spellbook, dip it in water. Blessing your magic marker and your media isn't a bad idea either.