Access Digital Photography

It’s a well known fact that digital cameras cannot capture the dynamic range of film. This doesn’t present a problem until you capture a scene like a sunrise or a sunset. If you set your exposure to capture the highlights, you lose detail in the shadow areas. If you set your exposure to capture details in the shadows, the highlights are washed out. One solution that comes to mind is the Photoshop capability to render an HDR (High Dynamic Range) image. Of course if you don’t have a tripod in your hip pocket, this is not a viable solution. The best option in this scenario is to capture the image using your camera’s RAW format, and then do the following in Photoshop:

1. Open the image in Camera Raw and drag the Exposure slider to reveal details in the highlight areas of the image. This causes the image to lose detail in the shadow areas, but you reveal the highights in all their glory.
   
2. Click Open.
3. Open the image again in Camera Raw, and drag the Exposure slider to reveal details in the shadow areas of the image. This will cause the highlights to blow out.
4. Click Open.
5. In Photoshop, select the version of the image you rendered for shadows and press Ctrl/Cmd + A.
6. Press Ctrl/Cmd + C to copy the image to the clipboard.
7. Select the image you rendered for highlights and press Ctrl/Cmd + V to paste the copied image into a new layer.
8. With the new layer still selected, open the Channels palette.
9. Ctrl/Cmd + click the RGB channel. This creates a selection based on luminance, which in essence selects the highlight areas of the image. Your next step is to feather the selection. The amount varies depending on the size of your image.
10. Open the Feather Selection dialog box (Ctrl/Cmd + Alt/Option + D).
11. Feather the selection by an appropriate amount. For a 12.8 megapixel value, I use a value between 120 and 175.
    
12. Click OK to feather the selection. At this stage you should have one large selection which comprises the pixels that are blown out on the layer you rendered for shadow detail.
13. Press Delete or Backspace. This deletes the unwanted pixels on the layer rendered for highlights. If you did a good job of feathering the selection, your image has a vastly improved dynamic range. If for some reason the image doesn’t look right open the History palette and select the state where you created the selection and then apply a different value in the Feather Selection dialog box. To complete the image, I applied the wonderful new Exposure filter by Alien Skin, which makes digital images look like they were shot on film. I chose the Kodachrome 25 preset. With a bit of practice, you can increase the dynamic range of most images in a few minutes, much less time than it took me to write this tutorial.

This entry was posted on Monday, August 14th, 2006 at 9:37 pm and is filed under Photoshop Tips and Tricks. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.