Paulo,Hi DG & COEDS,
I have taken your advice and hey presto it looks like it works. I tried it with a different dark image and it seems to be ok. Looks like I had a bit od dust on the mug or there again it could be a fingerprint.
My next load of mugs will be from another suppplier and i will order a sample as i now have 300 mugs to sell off.
Thanks for your help again Guys
I am not sure if this is the problem, or, one of them, but there are different kinds of coatings on mugs...
By that, I mean there is cheap coatings, and good coatings, in other words, better made mugs all around.
The cheaper coating ones are not to be used, or at least I don't use 'em, and was told (here) to not bother with them as they won't last.
The hard coated ones (hard coat inkjet) last and last, I use 'em for my coffee and so does my wife,, they are dishwasher safe, and so far, none of the mugs I have made have any problems.
When you said that you can scrape the coating with your fingernail that made me think you have the softer coating, which ain't good.
The brand I use is Cactus, they are also from China, but they are top quality, they have different grades, and are supposedly hand-picked to get the most round shape, which is better.
(I don't know if they hand-pick every one, but I haven't had any that were misshapen at all)
I didn't buy my mugs at the above place, I bought them locally at TOG.
If you plan on buying 300 of 'em, I'd definitely check into a hard coated brand, that may not have been all of your problem, but it could explain some of 'em.
I hope this helps some.