Taking Retina screenshots on a non-Retina displayEdit

Firefox

As far as I can tell, the best way to do this (for example, when you want to test Retina visuals on a machine that doesn’t have a Retina display, like a MacBook Air), you can use Firefox, go to about:config, and change layout.css.devPixelsPerPx from -1 to 2.

Source

Chrome

You can also do it in Chrome, but it is fiddlier:

  1. Zoom to 200%
  2. At the bottom of the JS console (Option-Command-J), click on "Emulation"
  3. Check the "Emulate screen" box
  4. Set "Device pixel ratio" to 2
  5. Make sure "Emulate viewport" is unchecked (otherwise the content gets resized)
  6. Uncheck "Shrink to fit" (it doesn’t seem to do anything useful)
  7. Uncheck "Enable text autosizing"