Apologies if this isn't the correct place for this sort of query, but I couldn't see an alternative.
If I use a template or theme developed by someone else and make changes (as allowed under gnu or CC licensing), at what point does it 'become mine'?
For example, if I change the background colour scheme and some graphics (say the main header picture), is that enough of a change for it to be a new theme?
I'm asking primarily so that I can change the credit to me (or even remove it entirely). To be fair, I do tend to leave a 'based on ...' message within the theme files.