I'm not sure if anyone has said this yet - 
because i haven't read through all the posts. I 
have done slight retouches before, much like your 
example with the VHD cel.

In reality, you are just retouching the scan - 
not the cel. You know that when you look at it in 
real life, that the dust and darkness isn't 
really that bad. It was just the scanner being a 
smacktard. I hightened the contrast of both my D 
cels because they were much too dark and were a 
rather false representation of what I saw in 
person.

However, there are retouches that should probably 
be noted - at the very least when they are being 
resold. Like smudging out paintchips or creases 
shown in a scan. In this respect, the touch-ups 
are definatly false advertising. 

~Tara