RAW preview vs. DNG preview


Photo of comedian Will Franken — by Joe Reifer

What you see above is a screen capture from my cataloging software, iView Media Pro, that illustrates the difference between the preview embedded in the original RAW file, and the preview in the DNG version. Which preview would you rather use to assess the quality of your images on the virtual lightbox?

Here’s the deal — if I take my RAW image and adjust it in a converter so it looks pretty, then it looks pretty in the RAW converter, and as any kind of derivative file from the RAW (PSD, JPEG, etc.). But when I look at that original RAW image as a thumbnail or in a cataloging program, the embedded preview is based on the original camera settings. Contrary to popular belief, Will Franken is not orange.

If I use Adobe Bridge to adjust RAW files, the adjustments show as long as I’m still in Bridge or Photoshop. If my now adjusted RAW file is viewed by another program, I’m back to square one. As far as I know, the same holds true for any other RAW conversion software. RAW adjustments are not portable between programs — each company has their own proprietary way of storing these adjustments.

One of the huge benefits of the DNG format is the JPEG preview contained inside your file reflects your RAW adjustments. If your cataloging software is set to show the preview embedded in the file, then you will be happily organizing, rating, searching, and sorting images that look how they should — not how your camera saw them at the time of the exposure. It’s way easier to assess image quality if you’re looking at a properly adjusted file. This little feature makes a huge difference to my workflow, and is alone almost worth the extra time it takes to convert to DNG.

So how do you setup Camera RAW and iView Media Pro to make this work? Yet again, I will recommend Peter Krogh’s The DAM Book for a detailed explanation. Here’s the short version:

Save Options for Camera RAW or the Adobe DNG converter

  • Format: Digital Negative
  • Check – Compressed (lossless)
  • JPEG Preview – Full Size

Camera RAW Preferences – DNG File Handling

  • Check – Ignore sidecar “.xmp” files
  • Check – Update embedded JPG previews: Full size

This means when if you update the Camera RAW settings for an image, the embedded JPEG preview inside the DNG gets updated, too. You take a small speed hit, but it’s worth it. See pages 126-127 of The DAM Book for more info.

iView Media Pro – Preferences – Media Rendering – RAW

  • Make sure “Use embedded preview (if available)” is checked

With these settings you’ll be using a preview in iView that reflects your RAW settings in both the Thumbnail and Media view. If you’re an iView user, try it out with a test file. Makes a huge difference.

I’ll be writing about another big benefit of the DNG file format in an upcoming post about copyrighting your work. I’ll also be discussing the acquisition of iView by Microsoft, and how DNG really is the best file format for the paranoid. Stay tuned.

3 thoughts on “RAW preview vs. DNG preview”

  1. Hi Joe,

    So I’ve made the setting you recommended and it works fine for any new adjustments. But is there a way I can reset all my DNG files that were previously adjusted/cropped using Bridge with the “update embedded jpg previews” turned off? There must be some sort of batch I can run? I do hope so and thanks in advance for your advice.
    Best,

    Jock

    PS Really frustrating trying to switch from Bridge to Lightroom (which isn’t set up yet to read my metadata) or Aperture (which won’t import metadata from Bridge export RAW settings!). So this is I why I am going to use IVMP–or at least until Lightroom is released. .

  2. Hi Jock -

    For files that were adjusted before changing your settings, try opening them in Camera Raw and choosing the “Export Settings” command in the flyout menu (circle with an arrow in it) just under the histogram. Try this on a few test files before doing a big batch. The DAM Book has a screenshot on p. 127.

    Lightroom and Aperture are not mature products yet when it comes to the finer details of Digital Asset Management. iView plays well with Bridge and the DNG format. I’m keeping my fingers crossed that iView continues down this well thought out path.

    Cheers,

    Joe

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