I have tried to do a print that has a fully black background..... It isn't as simple as it looks.
The first couple seemed to go a goldy brown across the middle, so I turned the heat down from 180 to 170 for 180 seconds and then the edges were faded as if there wasnt enough heat. I went through around 8 mugs and gave up!
I don't think it's an ink issue as the rest of the black bit looks great (as does the black parts on a normal print, text etc).
How do people find the perfect heat / time combination without using tens of mugs?