DaNGer! DaNGer!

I decided to try Adobe’s DNG converter for the same reason that I can’t help picking at scabs: I’m always curious about how a new workflow will feel. This, of course, is because I am a dedicated amateur and wanker. If I were a professional, the chances that I would risk my livelihood on a new workflow before it was tried and tested would approach zero.

DNG, for those of you not aware of it, is Adobe’s new semi-open standard for “raw” digital photographs. The theoretical pitch is as follows: camera manufacturers are each promulgating unique raw standards. Many of those standards change from camera to camera, so a Canon Raw file from a 350D is different from a Canon Raw file from a 30D. Propietary formats are bad! Photographers should keep all of their raw photos in DNG, which will always be supported, and since the standard is open, even if Adobe goes out of business someone will write tools to read and write it.

That’s the idealistic pitch. The practical pitch is as follows: “Adobe tools don’t know how to write metadata into all of these raw files, so we store them in “sidecar” .xmp files that have to be in the same directory as your raw file. Having two files is messy and bad! Convert all your photos to DNG, and we can put all that metadata inside the file. That will be nice and neat! Also, we like puppies.”

This was, to tell the truth, attractive to me: I have always hated those xmp sidecar files, and I have always loved cute little puppies.

There’s just one problem: the idealistic pitch isn’t quite true. For example, Photo Mechanic, a program that, as near as I can tell, is written by three guys eating ramen noodles in Washington state, can manage to write IPTC metadata into just about every major Raw file format without resorting to xmp files. Maybe it’s unfair to expect the guys from San Jose to do the same thing. But as long as I have Photo Mechanic, it’s a hard sell to convince me that I need to convert to a new product to read and write metadata in a single file.

But, as I said, I can’t resist the allure of changing my workflow for no particular reason, and since I’m currently evaluating several cataloging tools it seemed like a good idea to try out the DNG converter, since it would let me see how the cataloging tools handled it. I picked a couple of small directories, configured Photo Mechanic to invoke the DNG converter, held my breath, and dived in.

In terms of core functionality, everything worked more or less as advertised. My files were converted. The DNGs could be read by the cataloging tools, and by Bridge, and by Photo Mechanic, and just about every other tool I used. However, I found two problems that have convinced me that DNG is not yet for me.

First, the conversion seems to have lost some of the metadata in the CR2 files. Most of this is Canon-specific data – the sort of thing that you might lose, for example, if you converted to JPEG (white balance, serial number, etc). The truly crucial metadata (by which I mean “IPTC keywords and creation date”) were copied over correctly. So this by itself isn’t the showstopper.

Here’s the showstopper.



Now, let me be perfectly clear about what we’re looking at. These are not the actual raw files. The fidelity of the actual raw file in the DNG is perfect: it looks exactly the same as in my original .CR2. What we’re looking at is the jpeg preview that is embedded in the file. In simple terms, the DNG converter decided to “help” me by generating a preview that looks as if I opened it in Adobe Camera Raw and set all the checkboxes to “automatic.”

While I understand the rationale behind giving me this “help,” I really don’t want it. By the time my photos hit the DNG converter, I have already done an editing pass: I decided which photos to keep by chimping at the camera. The preview in the CR2 is essentially the same as what I looked at on the camera. The DNG preview is garbage, regardless of how technically correct it may be, simply because it’s not the same thing I was looking at on-camera.

I looked around for an option to just slurp over the CR2 preview, but it doesn’t seem to exist yet. This, petty as it is, will probably keep me from making DNG an essential part of my workflow in the short term.