A synology wouldn't be able to run a document management server software though, would it? Specifically Paperless (https://marinersoftware.com/product/paperless/) and MySQL. Source: about 3 years ago

I went through this a decade or so ago when I realized when I was moving that a quarter of the boxes I moved were full of paper. I am currently storing everything in Mariner's Paperless. Https://marinersoftware.com/product/paperless/e Everything is in PDF so easily exportable but the scanner integration and the workflow make everything easier. Source: about 3 years ago

I've been a big user of paperless from Mariner software. https://marinersoftware.com/product/paperless/. Source: about 3 years ago

You may want to try TagSpaces https://www.tagspaces.org/ or TMSU https://tmsu.org/ which provide mechanisms for managing tags of arbitrary files (not only EXIF or ID3 ones). - Source: Hacker News / about 1 month ago

The author of TMSU left a sibling comment to yours: https://news.ycombinator.com/item?id=37507343 > TMSU is a tool for tagging your files. It provides a simple command-line tool for applying tags and a virtual filesystem so that you can get a tag-based view of your files from within any other program. > TMSU does not alter your files in any way: they remain unchanged on disk, or on the network, wherever you put... - Source: Hacker News / 8 months ago

And what led me to build [TMSU](https://tmsu.org/). - Source: Hacker News / 8 months ago

I haven't used this myself, but I saw a recent announcement here about https://github.com/vifon/tmsu.el#features by /u/vifon which lets you tag files (with https://tmsu.org/ ) from dired, perhaps it would be possible to add features on top of that to colour based on tags? (e.g. Tagging "red" would colour it red). Source: 11 months ago

The TMSU Nautilus Extension seems to require you to install the command-line tool TMSU (a tool to tag files). Source: over 1 year ago