2005.03.03 18:04 "Re: [Tiff] LibTIFF question", by Bob Friesenhahn
I think you should be doing something like:
int *data = NULL;
TIFFGetField( m_TIFF, 50653, &count, &data );
Fields that are not pre-defined are normally treated such that you have to pass the count into TIFFGetField. The returned pointer should be to an internal copy of the tag value.
This feature does not appear to be documented in the manual page.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/