The Photoshop CS2 Book for Digital Photographers [Electronic resources] نسخه متنی

HDR and Exposure Merge

While Photoshop CS2 is the first version to compile High Dynamic Range (HDR) 32-bit images, you kind of have to think of this as more of a "technology preview" than a tool that will get a lot of use (at this point anyway), because thus far there are no monitors that can truly display HDR images or printers that can print the range of colors they possess. But there will be one day (and we'll all fly around with jet packs, too). Here's how to mess around with HDR and impress your photographer friends:

Step One

The magic of HDR is that it lets you merge multiple shots of the same scene (using a tripod), but you vary the exposure time for each shot (not the f-stopsthe exposure time). Then these are merged together to create one "megaphoto" with a dynamic range far exceeding what humans, printers, or displays can reproduce. However, dogs can see HDR and they love it! (Kidding.) So that's step one: Shoot multiple shots of the same scene and vary the exposure value (Adobe recommends two exposure-time value settings between shots, like 1/100, 1/250, 1/500, etc.). Once you've taken your shots, you can open them from the Adobe Bridge by navigating to them on your hard disk, then going under the Tools menu, under Photoshop, and choosing Merge to HDR.

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Step Two

When the Merge to HDR dialog appears, you'll see the results of the merge (and the photos used are displayed on the left side of the dialog). At this point, there's only one slider, which you can move to adjust the white point. You also get to choose the bit-depth, but if you leave it at the default 32-bit and open it in Photoshop CS2, there's a very limited number of tools or features that work on 32-bit images.