EDIT 10/07: Community bumped this Q, but I think we should first resolve the issues around closure before proceeding with this.
Following up on Vincent's proposal here I'm starting a list of questions about pixels, pixel density, ppi, dpi, etc. I'm also proposing a canonical Q&A.
- InDesign Measurements
- Does a DOT comprise of many PIXELS
- Andoid style guide - px to dp, how do i convert?
- Photoshop Vectors turned into raster images automatically
- What exactly is a "Pixel"?
- Convert PX to DP
- Should design dimensions be in inches (or any other physical dimension unit) instead of pixels?
- Are pixels in Photoshop logical or physical?
- What is pixel aspect ratio?
- High Pixel Density Images
- and more
- and many more
I realise this is quite broad, and can be sub-divided in different aspects. I'm open to suggestions from the community about how to handle this. If enough people think this should be divided up into multiple canonicals, I'm not against it.
Additionally, joojaa already attempted to do something similar with this Meta Q, but I think it's better to have a Q&A on the main site to use as a dupe hammer.