I understand that the walls of some color spaces are closer than others, so clipping will occur earlier. I also understand (and mention) in my last reply that there is a difference between baking in and not baking in data. You even say in your reply 'A B&W adjustment layer works on the underlying RGB data in that color space.', and this is exactly my point. If the underlying RGB data remains untouched, why can't we recover it using a second adjustment layer? You say: Once an adjustment is committed, baked into the pixel data, any channel clipping is permanent. This is true for Lightroom as well, except of course the adjustment isn't committed until you export a rendered RGB file. And Lr's internal workng space is linear ProPhoto, large enough so that you can push adjustments very far before it reaches gamut clipping. Again, you are actually agreeing with my argument - the values aren't baked in until export. The same is true of Photoshop - Unless I flatten the image or export a different format, all the original image data is still present, even if it is clipping because of adjustment layers. Indeed that is one of the main reasons to use adjustment layers. When I pull the exposure slider to the right in Lightroom and clip all my highlights, Lightroom still has access to those values and By moving the whites slider to the left, I can bring those outlying values back into the color space. In Photoshop, I can increase exposure to a point where one or more channels clip in a wide number of ways (for example using the Black and White adjustment layer), and Photoshop still has access to the underlying data (I can easily manipulate the adjustment layer to bring the values back into the color space), yet it offers me no way to bring those values back in the way that Lightroom does. So my question remains unanswered - If Lightroom is able to recover blown values, why can't they be recovered in Photoshop when they have been blown through use of adjustment layers and they original image data was not blown? The color space is effectively irrelevant to my question as it is still possible to clip and recover highlights in Lightroom (which uses ProPhoto)..
... View more