Hmmm,
I am not seeing that, the post workflow was simpley to adjust exposure, reduce saturation a touch then a tinted overlay set to colour dodge and the 2o/c spot lighting effect, which brought out a nice tone IMO but did produce the unsightly vignettes.
I can't for the life of me see what you are, although I know what you mean and I have seen it in both some of my own post work and in others.
I usually see it with ps gradients at low resolutions and with HDR effects both real and pseudo, but I am no ps or indeed photography expert!
LJ
----Edit----
on closer inspection I do see them (you must have a big monitor), great spot, thank you, I will further refine my post to avoid these in future!
btw, any tips on that?
LJ
----Edit 2----
Ok well I have found out what it is and it is an artifact fom the PS Lighting effects. Thank you Alpha, sometimes a good kick gets me working harder!