This is really something that I have never used before, so I’m glad that I ran into this tutorial. Essentially, when I usually open up a RAW file in Adobe Camera RAW (I do use Lightroom most of the time for this), I would open into a TIFF or PSD image file. Calvin Hollywood, who’s actually in Germany, talks about how he actually opens the RAW file as a Smart Object. The way you do this is by holding the shift button when you’re in the Camera RAW dialog, which changes the Open Image button to Open Object.
The reason that this is powerful is because anytime you double click on the Smart Object layer, you will reopen the Camera RAW window, which allows you to readjust the sliders again. It’s literally like having Lightroom’s non-destructive RAW approach in Photoshop. Furthermore, if you right-click on the RAW smart object layer and choose New Smart Object via Copy, you will now have a copy of the original RAW smart object with its own independent Camera RAW adjustments. This means that you now have multiple instances of the same RAW file with its own dedicated Camera RAW settings.
The example he shows in his Youtube video is adding the crunchy HDR-like details on the second layer, but using the colors from the first layer. He changes the blending mode of the 2nd layer to luminosity so only its lightness value gets passed through the first layer.
Another application of this is if you want to do composites from different RAW files. You can open each RAW files as a Smart Object and put them in one file. You can then adjust each RAW files separately while still taking advantage of Photoshop‘s layer blending modes.
I tried this one of my own photos and although I can get the same effect with just one Camera RAW with clarity, it’s good to know that I have options and the added flexibility of independent multi RAW adjustments.