That is what Photoshop's Luminous selection does. And like any selection you can adjust it using other Photoshop tools. You are selecting shadows and highlight. Inverting the selection basically switched from Highlight to Shadows. The Selection is like a gray scale of your image. Shortcut Ctrl+Alt+2 or Ctrl+Click on the RGB channel or click the first icon the dotted circle in the bottom of the channel palette. Add it as a layer mask to select Highlights and shadows. Adjust the layer mask using adjustments like Curves and Level.
To isolate your selection I created a layer from your selection Ctrl+j and added a luminosity mask Ctrl+Alt+2 then click on the add layer mask icon in the layers palette. Then I Adjusted the mask to select highlights more and the shadows less Ctrl+L or M. Then added a level adjustment layer I clipped the the new layer to brighten the torn paper selected by the luminosity mask. Its not very hard to do getting it right takes practice
If you converted the CTRL+J layer to a smart object layer you may be able to use ACR as a smart filter and use its shadow and highlights adjustment. However you may have more control over shadows and highlights via luminosity masking. There always seems to be more than one way to do something using Photoshop.