Printed photos too dark.

ePrint is a great facility, but the problem I have is that when I print from my photo file the resulting print, although sharp and detailed, is far too dark. The same image, (a photograph of a painting), sent as a file to a processing lab, is returned virtually the same color as the original. I suppose I could adjust the brightness before I send to the printer, but that defeats the object.
Any suggestions@
Regards,
John