[Openicc] adding informations to ICC profiles

[Graeme Gill]

Kai-Uwe Behrmann wrote:

> in order to gather and store information about the device chain state 
> during calibration, I have written a proposal:
> <http://www.oyranos.org/wiki/index.php?title=Device_Settings>
> I like to attach device settings informations as text to existing 
> profiles.
> 
> Goal is to maintain ICC spec conformance. 
> 
> The technical easiest way would be an extra tag dedicated for
> this purpose.
> 
> Is a device settings 'text' tag allready specified by ICC?
> I only found an pdf containing a tag list, without enough further 
> informations about additional tags.

Most custom tags are undocumented.

Note that for some versions of the ICC spec. (V2.4), there is the
"deviceSettingsTag", which was aimed at representing some of the
types of information you are referring to. It seems to have
been dropped from latter versions of the spec. though.

> Is it possible to take an existing profile and add a new 'text' tag, as 
> descibed above, without breaking any copyright?

I don't quite see where any problem would lie. To add another
tag to a profile requires parsing it and re-writing it. To this,
the software must preserve unknown tags (icclib won't do this
currently, although it's on my "todo" list.)

I have come across another proposal similar in nature to
what you are suggesting, but can't remember where I saw it.
One of the comments I remember was that having a textural
representation of settings is almost useless, since there
is then no sure-fire way of systems recognizing the settings -
you're just left with heuristics. Specifying a formal
way of recording configuration that is flexible
enough to cope with existing and future printing systems
is daunting though. (The "deviceSettingsTag" is complex
and not fully documented, and it probably doesn't cover
everything.)

Graeme Gill.