HI Chris and welcome to the forum ;)
What time and temp are you using with the DF1? What software are you printing through and are there any other profiles being used in there?
There have been a few posts in the past regarding colours turning brown so may be worth a quick search for some more help. Drop Martin a line (if he doesn't respond on here first :D )
I'll move this post into printing problems as it's better suited there.