B&W horizontal banding comes and goes when viewing in PS6

[Owen Dawson]

So i thought i was seeing things yesterday until it happened again just now.
i'm doing was doing a conversion to bw in nik software and i noticed yesterday that in the darker area in the sky i was seeing some color cast and or horizontal banding(PS6)
i clicked on the the bottom to view doc profile and i looked back at the color cast and it was gone. i just closed the image and reopened it from LR and its back. Yesterday for no apparent reason it would change from a colorcast/banding to a correct color. i don't ever see the issue when viewing in LR3
any ideas of why this may be happening. i've never noticed it before. i'm using a new dell U2711 ultrasharp calibrated monitor.

 

[ALB68]

Hi
Welcome to our forum! Make yourself at home.
I have to say that I personally don't have a solution or diagnosis on this issue, The first question in my mind is how do you have your color setting working spaces set up? Edit/Color Settings

 

[Owen Dawson]

everything is set to prophoto RGB

 

[ALB68]

everything is set to prophoto RGB

That would be correct. Some people will stick output devices in that and that is not correct. You apparently know better. We have some other members that will be more qualified to help you than I. Be patient and someone will be along in a bit I'm sure.