ACR within Photoshop clipping vs Lightroom clipping

[Melolaur]

I am confused. I can look at the exact same image in both Lightroom and Phtoshop. In Lightroom, there is no highlight clipping, but that image will show clipping in ACR within Photoshop. When I pixel peep the image in PS, all detail in intact and look properly exposed. Shouldn't they be the same? Is there a way to synchornize the valures?

[D Fosse]

ACR shows you the histogram for the data as encoded into the chosen output color space - sRGB, Adobe RGB etc.

Lightroom shows you the histogram for its internal working color space, which has ProPhoto primaries, but a linear tone response curve. For the purposes of the histogram, an sRGB tone curve is used instead, just to make more visual sense.

In any case - if you turn on soft-proofing to sRGB/Adobe RGB etc in Lightroom, the histograms show the same thing and will match.

And then the question is what kind of highlight clipping you have. Is it all three channels, or just one? If the latter, it's gamut clipping, and the ProPhoto-based color space of Lightroom may be able to contain it all. Converted to sRGB or Adobe RGB it may be out of gamut and clip one channel.