ICM Profiles

On this page there is a set of ICC profiles, also knows as ICM profiles. These have been created from the data on Bruce Lindbloom's site, as well as information from Adobe, using the little cms toolkit.

Profiles tell you system how to display colors - they contain three key pieces of information:

  1. An exact definition of what the gamut of the color space is - in simple terms, what exact shade of red the R component is, the G component, etc
  2. A white point - these are often specified as a "D number", one of the CIE standard illuminants e.g., D65 (6500K, overcast daylight) or D55(5500K, warm daylight)
  3. A Gamma curve - the way that we see light is non-linear, and many color systems mimic this

You can use these profiles in a number of ways:

  • If you have a raw developer program, such as Capture One, that directly supports ICC profiles, you can load and use these directly. So, for example, if under Capture One you wanted the screen readouts to be in WideGamut, you would just load WideGamut.icc as the output profile.
  • You can also convert color on the Mac by using the ColorSync utility's calculator; just select the appropriate profile in the calculator screen.

The profiles are in a single ZIP file, ICCProfiles.zip.

The root of the Zip file has the following profiles:

AppleRGB.icc
CIERGB.icc
MelissaRGB.icc
ProPhoto.icc
WideGamut.icc

The MelissaRGB profile deserves some explanation. Melissa RGB is not an "official" color space, but is the combination of the ProPhoto color space, with an sRGB gamma curve. It's important because Melissa RGB is what Lightroom uses for its readouts. Specifically, the RGB values you get as Lightroom readouts are in this space. Note that the Melissa RGB profile I'm providing here has the real sRGB gamma curve. The sRGB gamma is close to a 2.2 gamma, but is linear at low values. So, if you take a readout of the darkest patch of the GretagMacBeth chart, there is is about a 1.5% difference between the reading using ProPhoto at a 2.2 gamma and a true Melissa RGB profile.

I also provide some alternate profiles in the "Alternate" directory of the ZIP. This includes a "ProPhoto gamma 2.2" file, for those that want to compare to the Melissa RGB version. These are all either at different to normal gammas, or different to normal white points:

MelissaRGBD65.icc
ProPhoto22.icc
ProPhoto22D65.icc
ProPhotoD65.icc
sRGB Gamma22.icc
WideGamutD65.icc

The file names should make the differences clear.

In order to install these profiles, you need to do the following:

  1. On Windows systems, either just double click, or copy to the \WINDOWS\system32\spool\drivers\color directory
  2. On Macs, copy to the /Users/Library/ColorSync/Profiles folder, or if you want them to have them available to all users and you are an administrator, to the /Library/ColorSync/Profiles folder