Color accuracy is of the most importance in art documentation, especially when it comes to paintings. I want blog here about my color management workflow and tools.
Here is a video of the color management workflow processes I describe below.
Step 1. Camera Calibration. Due to differences in technologies and variables in manufacturing processes every camera captures colors a bit differently. Even two identical cameras from the same company are a bit different. Even if the Raw processing software you are using could have included a profile for the model camera which you use, you can get even better results when you create a profile specifically for the RAW output of your camera.
To calibrate my Nikon D800 I use X-rite ColorChecker Passport and its bundled software. ColorChecker Passport Classic Target is the industry standard color reference target for creating DNG profiles and for evaluating specific colors.
Here the sequence of instructions to calibrate your camera. More exact instructions are provided by the manufacturer here.
- Take a RAW picture of the X-rite classic 24 patches target.
- Save the picture in DNG format.
- Open ColorChecker Passport software included with X-rite ColorChecker Passport.
- Drag and drop the DNG image in the software main windows and click “create profile.”
- When you turn on Camera Raw you will see the new profile in the camera calibration tab.
As an example compare the picture of the ColorChecker with the custom Nikon D800 camera calibration and the Adobe Default camera calibration.
Step 2. White Balance. X-Rite ColorChecker Passport has a grey target for White Balance so you can create custom in-camera white balance for a consistent white point in a set of images, eliminating the need to correct each image later. White balance is different from the camera calibration seen in the step above, The first one correct for different lighting while the second one correct for different rendering of colors by different cameras.
By the way, for outdoor photography I use expodisk. This expodisc is calibrated for 18% light transmission and neutrality in the visible spectrum (400nm to 700nm) and it is used as an incident ambient exposure tool (as you would with an 18% gray card), as well as for white balance. It comes handy in all those outdoor photography sections where you do not want to risk damaging your color checker target.
Step 3. Monitor calibration. For last photo-editing on your images or just to be sure your images look fine you must calibrate your monitor. Monitor calibration is recommended every month or earlier. I use X-rite i1 Display and its i1 Match 3 software to calibrate my laptop monitor.
AIC Photo Documentation Target. Once the color management workflow is set up, I document art with the AIC Photo Documentation Target in order to always have color checker reference in the actual images. This target has also some more features such as an illumination guide associated with a parallelism indicator, a size scale, and an area for date and object identification information. I added to it a cadmium red and forensic UV swatch which I use respectively to calibrate Infrared fluorescence and UV fluorescence.