Flickr machine tags for film photos

For the past few months I’ve been taking photos using black and white film in my old 35mm SLR camera, more of which another time. When one uses a digital camera, the details of the camera and shot are embedded in the image as EXIF data, and can be viewed when uploaded to Flickr. I wanted to record some of this information for my film photos taken on film, but wasn’t sure how.

At first I just noted some details in the comments of each photo (in both iPhoto and on Flickr), eg:

50mm 1/60 f5.6
Kodak Tri-X 400

Which is better than nothing, but is pretty ugly. And, these days, plain text feels rather dead and not a useful way of storing such information. Only a dumb old text search would find me all the photos shot with a certain lens or film, for example.

A year ago Paul Mison wrote about extracting EXIF data from his Flickr photos and putting them into Flickr machine tags, those ugly computer-readable tags that associate other kinds of information with photos.

It made sense to add the information I wanted to store into machine tags. It would have to be manual, but that’s not too hard, given how much time I already spend on applying metadata these days. I copied the kinds of tags Paul was generating and added them to my own photos:

film:name=kodak tri-x
lens:lenstag=pentax 50mm f/1.7

But this doesn’t cover information about the individual shot — shutter speed and aperture. I chatted with Paul and looked round his machine tag browser but there didn’t seem to be much widespread use of what I wanted. So I made up my own tags for this purpose:

photo:shutter_speed=1/60 sec

Which does the job. Now I can see all my film photos shot on Kodak Tri-X (er, all of them) or with a shutter speed of 1/15 sec.

Looking at the latter URL, which has translated “1/15 sec” into “115sec”, I can see there will be a conflict with any long exposures measured in whole seconds. Maybe there’s a better format to use?

Anyway, just thought I’d write that up in case anyone else was wondering the same thing, and also wanted to simply copy someone else’s method.


  • Perhaps you could denote fractions with a dash, eg ‘1-60 sec’. I can’t think of any potential collisions.

  • Yes, machine tags are normalised; the example I used is that 'both -1/3EV and +1/3EV show as just "exif:exposure_bias=13ev".' For exposure time, perhaps a better idea would be to use decimal timings (so 1/60 becomes 0.01666), since even the loss of the dot isn't too troublesome (unless people are in the habit of using leading zeroes).

    On the other hand, very long exposures are pretty uncommon, so the normalised URL form of a fraction is probably Good Enough, especially as API methods can operate on raw tags.

  • Hi, Paul (comment above) alerted me to this post.

    I created the FilmDev website for people who develop their own film.
    It uses Flickr machine tags to link photos to film developing "recipes".

    I've been thinking about adding something like the above for film and developer used but hadn't gotten around to it yet - this post has given me the impetus I need. :-)

    As you've worked out a system I think I'll adopt yours - adding analogous ones for the developer that was used too.

  • Great, sounds good Darren. I'm too lazy/busy to develop my own but it sounds like what I'd want to use if I did!

  • Normalisation of aperture seems more likely to lead to confusion than exposure (which has a reasonably obvious solution as above). f/1.4 and f/14 end up looking the same, and both are common.

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4 Nov 2009 at Twitter

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