[popo]

For some while I was frustrated trying to get some sort of detail out of red flowers which were to all intents and purposes correctly exposed, but showing up 255 in the red band. I tried underexposing but as soon as you bring up the exposure again in PP your back to square one, the bottom line is I got no further with curing the problem than just taming it with the HSL colour control in CS6, reducing red and magenta saturation as a standard stting for all RAW images.

That's a different problem I think. Flowers can be very strong in some channels like red, but the metering (at least on Canon) seems to be heavily biased towards green. So it will over-expose the red channel in those situations. The red channel is much higher than others, so back in processing you will have trouble getting other channels up keeping balance without clipping the red.

 

I have the same problem at the opposite end of the spectrum when photographing my marine aquariums. The lights on those are really high kelvin so blue channel is very strong with little in red/green. Blue is often clipped if I don't first adjust the camera metering manually. My other workaround is to use a yellow filter which takes the blue down a notch, but colours are hard to balance afterwards.