My project requires access to jpg metadata, and I just completed a
file reading utility. Original file is a DNG raw image made with my
digital camera. Using PhotoShop CS2 v. 9, I converted to jpg and
manually added text data to the appropriate IPTC data fields in the
File Info screen of PS.

Test results returned accurate data for 32 known EXIF/IPTC fields, 3
of which (x- and y-resolution, and resolution units) were
duplicates. They showed up near the beginning and again near the end
of the file.

The program also captured Field 50741 (C635 hex), value = 1. This
field is not listed at
http://www.portfoliofaq.com/pfaq/v7mappings.htm. Any clue as to what
this is, and a pointer to a better listing of fields, would be
appreciated.

Missing from the results were the values for keywords and caption
(object title) that I entered in PhotoShop (the other text entries
were returned by my reading program). I can work around both of
these issues, but wondered if anyone can shed light on what is going
on. If one of you have a proprietary reader, I can send you a copy
of the jpg (129 KB). That way I can know if the data are present and
are just being missed by my program.

Would also like to decode some numerical field values like Exposure
Program, Metering Mode, etc. Any pointers appreciated.

Jack Cane