Reader Bill Baum writes in asking if it’s possible to batch convert DNG files to JPEGs. Bill says that several years ago, he converted several thousand images to DNG, but now wants them as JPEGs to ease the process of working with them in Nikon Capture NX, which doesn’t natively read DNG files. Fortunately, if you have Photoshop CS2 or CS3, you can easily use Bridge to batch process DNG conversions into JPEGs, Photoshop files, or TIFFs.
DNG files are a little easier to work with if you just remember that Photoshop thinks of them as raw files. So, anything that you would normally do with a raw file can be done with a DNG file. Therefore, the same techniques that you use for batch processing raw files using Photoshop Camera Raw can be used for batch processing DNG files.
The easiest way to manage these batch processing chores is using Adobe Bridge. In Bridge, select the DNG files that you would like to convert, and then choose File > Open, or press Return. (You can also press Command-O, or Control-O if you’re using Windows.)
If it’s not already running, Bridge will launch Photoshop, and open the selected DNG files in Camera Raw. Because you’ve opened multiple images, all of the selected images will appear as thumbnails in the left side of the Camera Raw window.
Click the Select All button to select all of the images currently opened in Camera Raw, then click the Save Images button. (If you’re using CS2, then you’ll see a Save Images button at the bottom of the window.) Camera Raw will present the Save Images dialog box, which lets you specify naming conventions for the converted files, as well as a location to save them. Most importantly, it lets you select a format to save in.
Configure all parameters to taste, and then click the Save button. Camera Raw will begin to convert your images, and will provide feedback at the bottom of the Camera Raw window. In Bill’s case, this might take a while, since a few thousand images will require a bit of time to convert. However, the conversion is a completely hands-off operation.
As with all batch operations, be sure you have enough disk space to hold your converted files before you start. If you run out of space, the batch operation will be interrupted, and trying to figure out what’s been done and what hasn’t is almost always a hassle when a batch interrupts.