How can I darken the printing of a jpg file?

I scanned a hand-written sheet into the PC.

Hand written sheet was in ink, and therefore plenty dark.

When I print the jpg file, the printing is so light it is nearly not readable.

When I print another file, that file prints ok, so I conclude it is not the printer.

 It must be in the reading of the jpg file-----------and I know zip about that.

 Anyone know??

Thanks.