File size

Modern file formats can seem enormous (video, high-resolution photos, sound recordings). Should you store these big files or compress them? It all depends what you want the file for.

For example image resolution can vary widely and so does the file size. Image resolution is often measured in ppi or pixels per inch, also called dpi, dots per inch. If you want to view images on screen, then 120ppi is fine (or even less), but print really needs 300ppi for a nice clear picture.

And if you want to be able to crop out smaller pictures from within the larger one, e.g portraits, then the more the better so that the resulting blown up bit will still have a good resolution itself. You may not know what future hsitorians want out of the photo. For example, I'm into railroads, and much valuable historical information is derived from the "uninteresting' backgrounds to photos shot for other reasons. Likewise restorers of historic buildings have been known to recover wallpaper patterns from the background of old portraits, and clothing historians to extract lace patterns.

So you really need two versions of a file: one small format for on screen e.g. shown on websites or for emailing, and one nice big one for filing away for history.

Once upon a time (like four or five years ago) we worried about the cumulative size of lots of large-format files, but gigabytes of storage come cheaply now.

So shoot/record them as big as you can: high resolution photos and videos, high sample-rate recordings. Cameras these days take SD cards which are getting dirt cheap so buy the biggest you can and shoot the biggest you can.

Then for every directory of files, have a subdirectory into which you compress smaller-format versions of the same files. Some people have the time to compress everything. Some of us compress as needed.