Technical Q&A QA1136

ICC Profile copyright field

Q: I'm writing an application which can extract embedded profiles from documents. I notice ICC profiles have a copyright field, which would impose restrictions on redistribution of profiles which have this field set. How should my application handle this?

A: The ICC specification (see <http://www.color.org>) defines a pair of bits in the flags field of the profile header which establish an honor-system for protecting embedded profiles.

Here are the general rules:

1) Profile creators that want to protect the profile should set the cmEmbeddedUseMask bit.

2) Applications that embed a profile should set the cmEmbeddedMask bit before embedding.

3) Applications that extract an embedded profile to disk should check that the cmEmbeddedUseMask is not set.

Here are the definitions for these bit fields, taken from the ColorSync header file CMICCProfile.h:

enum {
        /* these bits of the flags field are defined
        and reserved by ICC */
    cmICCReservedFlagsMask = 0x0000FFFF,

        /* if bit 0 is 0 then no embedded profile, if 1
        then embedded profilev */
    cmEmbeddedMask                = 0x00000001,

        /* if bit 1 is 0 then ok to use anywhere, if
        1 then ok to use as embedded profile only */
    cmEmbeddedUseMask             = 0x00000002,
      ....

[Apr 08 2002]