2005.12.22 23:32 "Re: [Tiff] Custom Tags, Private Ifds and other questions", by Joris Van Damme

David,

I do realise that a private Ifd would hide values from people

> using tiffinfo

Not necessarilly. I don't know what is the current state of tiffinfo, but if you choose data type IFD for your private tag that links to the IFD, then this sort of code can easilly (be made to) pick up on things and show them. This sort of thing is the reason why I recommend the IFD datatype.

> and not work when copying images

Strictly speaking, that goes for private tags and for private IFDs alike. Not so strictly speaking, submitting info on your tags to the tag directory can help make known that your data is safe to copy given certain operations like unedited page copying. But this too, goes for private tags and private IFDs alike.

Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be/
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html