Reply To: [Solved] Etched (engraved) Line for Any background color

[Senff]

You’re going to have to use opacity if you want to use it in all colors. Something like this:

http://codepen.io/senff/pen/fsvbd

It won’t be perfect for every single background color, but you can play around a bit with the color values for the line (currently full black on top, full white on bottom, and opacity of 0.4).