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Sometimes processing raw files is a compromise. For example when adjusting the exposure to make the sky look its best results in the foreground being too dark. There are things that can be done during capture to mitigate the problem. Use of a Graduated Neutral Density filter will darken a sky relative to the foreground exposure. Or taking an exposure bracket sequence and process as an Exposure Blend or as a HDR. But what if we didn’t do these things and the dynamic range is just to too great to have detail in both the highlights and the shadows from a single file? One solution is to take advantage of the “hidden” dynamic range of a raw file and to process that raw capture twice, once for the highlights and again for the shadows, and to then blend the resulting files in Photoshop.

As with most things in Photoshop there are a number of ways to accomplish this. Here is one way that is efficient, relatively quick, and straight froward. Smart Objects are at the heart of this technique. Yesterday I did a post on Smart Objects. So if you haven’t read it, now might be a good time to take a look at it.

 
In this technique we are going to use two Smart Object layers based on the same raw file. However if we simply duplicate the Smart Object layer the technique will not work. As I mentioned in the Smart Object post yesterday Smart Objects have a copy of the source file embedded in them. If we just duplicate the SO layer we are only making a second instance of the same SO. And if the SO is a raw file and we re-open one of them in ACR and make edits, those same edits will appear in the other instance of the SO. This will not work for our purposes; we need two independent SOs based on the same raw file. To get the second independent SO, right click on the SO layer. Then in the contextual menu select New Smart Object via Copy. Now we have two independent SOs from the same raw file.

(Update: On his Adobe Photoshop Killer Tips site Matt Kloskowski has a short video that shows the differences in these two different ways of making a copy of a SO layer.)

Steps to the technique:
I usually wait until I have the image in Photoshop before optimizing either the highlights or the shadows. That way when I look at the file in Bridge or Lightroom I see “reasonable” image.

1. Open the raw file as a Smart Object.
       1a. Bridge/ACR: First open the image in ACR. After compromise settings are finished hold down the Shift key and Open Image will change to Open Object.
       1b. Or if, like me, you almost always open raw files as smart objects, you can make the default setting for the button to be Open Object by checking the Open in Photoshop as Smart Object in the Workflow Options dialog (Looks like a hyperlink at the bottom of ACR window).



2. Right click on the SO layer. From the contextual menu select New Smart Object via Copy.
3. In the layers panel double click on the bottom layer’s thumbnail. This will open ACR. Optimize for either the highlights or shadows. Save will bring you back to PS and that layer will be updated with the edits you made.
4. Double click on the second SO layer to open it in ACR. Optimise for either shadows or highlights. Again Save to update layer.
5. Blend the layers so that highlight information comes from one and shadow information comes from the other. The details for this step are worthy of a least a couple of posts by them selves. So I won’t go into great deal but simple outline what to do.
     5a. The most common way to do this is to add a layer mask to the second SO layer to hide part of the layer so that information from the layer below will show through where you want. This can be accomplished by making a selection before adding the mask or by simply painting on the mask.
     5b. Use the Blend If Slider in the layer effects dialog.

BTW, this technique is not limited to using different exposure settings for different parts on an image. I often use this technique to apply a warm White Balance to part of the image and a cool WB to another part of an image. I’ll show this tomorrow.