Is it possible to extract the IPTC information of many scans programmatically?

Question

I have several hundred jpeg-scans of negatives. For some of these, I stored a textual description of the picture in the Caption-field of the IPTC metadata. (Whether it was a clever idea to store it there or elsewhere is a different question). I need a way to programmatically get out the text from all scans.

I.e. what I need is a tool which dumps the IPTC of all negatives programmatically. I can access the IPTC info in Irfanview by clicking buttons, but this is not practicable for more than a handful of scans. It needs to be programmatically in batch, ideally on the command line / bash shell, ideally with ASCII ouput.

Is this possible, and how?

Answer 1

There are a number of free and open source tools that will do this, for Linux, Mac, or Windows. If you just need something very simple, jhead should do. Put it in a loop and output the result to one or more text files.

If you need more sophisticated options, you can step up to one of Exiv2 or ExifTool. These can read and write all sorts of metadata, including IPTC captions. Both programs are good. Exiv2 might be a little faster and is easier to embed in C programs, but that doesn't really affect you. ExifTool is probably more full-featured, but I don't think it'll matter for your basically-simple use case. Take a look at the docs and pick whichever seems easier to you.