Photoshop seems like one of the most difficult programs to work via VNC.
I think it's actually the opposite. Usually only a small amount of the screen is changing, so response is fast. For full-screen or complicated effects they can provide more CPU horsepower than your average laptop, so the operation may actually complete faster, even if screen redraw takes more time.
FWIW I've used Photoshop over Remote Desktop in the past and with a good connection it feels perfectly usable. There's a little input lag which is only noticeable with sweeping brush effects, not UI interactions, and like I say large area screen redraw (e.g. scrolling) suffers. There's no visible compression or artifacts and I don't see why color correction would be an issue.
FWIW I've used Photoshop over Remote Desktop in the past and with a good connection it feels perfectly usable. There's a little input lag which is only noticeable with sweeping brush effects, not UI interactions, and like I say large area screen redraw (e.g. scrolling) suffers. There's no visible compression or artifacts and I don't see why color correction would be an issue.