Camera Profiling

Two Methods

There are two general methods for profiling cameras:

• • Profiling after file rendering
  • Profiling in the raw image decoding pipeline

Let's look at how they work.

Profiling after file rendering

It's possible to create a profile for your camera that is applied to the image after the file has been rendered. The profile is applied in Photoshop once you've created a TIFF or JPEG file, and only then do you see how the color will be corrected. This method can work reasonably well for product photographers, but it presents a significant workflow challenge for photographers who use parametric image editors to do most of their work.

Profiling in the raw image decoding pipeline

Some software also offers the possibility of including a profile in the raw image decoding pipeline. This has a few advantages:

• • The profile is applied during the raw conversion, as part of the decoding process. This is a cleaner way to handle the color transformation, and should produce fewer artifacts.
  • The profile is applied as the user works the controls in the raw processor, so it's more wysiwyg.
  • The photographer only has to create rendered files when there is an actual need for output, rather than as part of the general image adjustment process.

Creating a camera profile

There are several pieces of software that can create a custom profile for you. One of the easiest to use is the DNG Profile Editor that is offered free from Adobe Labs. A profile can be created that is inserted in the rendering pipeline for Lightroom 2.x or later, and Adobe Camera Raw 5.x or later. This profile can be added to the profiles folder that ACR and Lightroom use and then used as a starting point for image adjustment.

Shoot the target, build the profile

In order to create the profile, a photographer must shoot a very evenly lit picture of a Gretag Macbeth color checker chart. The image is fed into the DNG profile editor and run through a process that creates a custom profile (this is not a true ICC profile, but rather a calibration file that works the same as an ICC profile). Once the profile is created, you can apply it to your images in Lightroom or Camera Raw (ACR).

Preserving the rendering

Because programs like Lightroom and ACR don't bake the changes in to the file, there are some considerations to take into account regarding the future accessibility of the rendering you make with a custom profile. If the profile is missing from the computer that opens the raw file – even if it's using the same version of the software – then the rendering will simply change. If you want to keep this "unbaked" rendering, then you will want to attach the custom profile to the image file itself. The DNG can contain the profile that is used to render the file, making it portable between machines. A feature of the DNG profiles is that they are backwards- and forwards-compatible with different versions of ACR.

Additional options

Capture One and Bibble also offer the ability to render a file with a custom profile (in this case, a standard ICC profile). You need to use ColorEyes software (available as a separate purchase) to create the profile. Note that this profile is not embedded in the file itself but lives in the profiles folder of your computer. In order to preserve the rendering, you'll want to manage and preserve these profiles; make sure they are installed on any other computer using Bibble or Capture One to render the file. Another aspect of creating and using ICC camera profiles is that they must be used with the same version of the software that created the original target files. There are other software applications that can be used to create custom camera profiles, such as X-Rite Profile Maker, however most of these work best for creating profiles for specific lighting setups — making them best suited for studio or catalog shooters.