How can I preview DNG files in OS X Finder, with changes?

Question

Can I somehow get my DNG files to preview in Finder with my applied changes?

I write my changes to the DNG metadata, but Finder previewer is not able to pick up on those, even though it does preview the file (in original condition).

Answer 1

The MacOS X feature that's responsible for showing you previews in Finder, Spotlight, standard file dialogs, etc., is called QuickLook. QuickLook needs an importer for each type of file that you'd like to preview. For standard types like text files, JPEG and PNG images, sounds, and others, the system has built-in QuickLook importers. In other cases, applications provide importers for their own files. You can find the importers installed on your system in the following locations:

• /System/Library/QuickLook/: Importers provided by Apple as part of a standard OS X installation
• /Library/QuickLook/: Importers installed on your machine available to any user. This is where a 3rd party application would normally install an importer.
• ~/Library/QuickLook/: Importers installed in the current user's account (the ~ indicates the home directory of the current user, e.g. /Users/johnnyappleseed). Importers installed here are only available to the current user.

It sounds like Adobe provides an importer for DNG files, but perhaps theirs has a problem or perhaps there's a newer version you can download. (I don't use LightRoom so can't offer firsthand advice there.) I'd start by checking Adobe's site or pinging their support people or forums.

It's entirely possible for third parties to create QuickLook importers if they know how to read some file type. A quick search turned up DNG Suite for MacOS X which might be worth a shot. There may be others as well.

Answer 2

The best QuickLook preview plugin for RAW files which I've found is Raw Right Away. Unfortunately it's App Store only (I'd prefer to buy direct and not be dependent on Apple for access).

Raw Right Away doesn't just handle DNG but RAW files from basically every manufacturer and camera (there may be some edge cases but I haven't run into them and I've used Raw Right Away with the RAW files across twenty-odd cameras and four manufacturers).

What Raw Right Away will do for you will is not just previews but EXIF information and a very good histogram. Here's what the preferences look like.

As you can see there are some very useful options here. Even the slow more accurate histograms and rendering seems pretty fast on i7 processors.