my pictures are dull and faded when i tried to heat press a mug

[plugy]

Make sure the press is set on Centigrade.

Jack

I have now set press to 240 and for 180 seconds and still the prints are dull.
When they are printed they are dull, maybe here lies the problem.
I am useing heat sub paper with epson p50, i have tried setting the paper to matt and photglossy, set to best photo and still very dull when printing am now stumped.