K20D shadow detail - clipping in ACR?

I'm just processing some shots I've taken recently which have quite strong colours, when I open the image in ACR and use [alt] with the "black" (shadows) slider ACR shows yellow patches in the image, reducing the black slider makes a slight difference but not nearly enough

This seems to be a colourspace issue as if I change from Srgb in ACR to prophoto the yellow areas disappear - Argb makes little difference

Would appreciate some advice on this

thanks

Simon

Personally I work in LR2.4. Same ACR is used there. I always work in the default colour space ProPhoto RGB.(as wide as space that's possible) Only for web use I convert to sRGB.

I have no hard facts to support this method others than my gut feeling and the opinion of M.Reichmann and Jeff Schewe stated in several tutorials they presented.

HTH,

Martin.