A Simple Web Developer’s Guide To Color – Smashing Magazine
▻https://www.smashingmagazine.com/2016/04/web-developer-guide-color/#creating-harmonious-grays
Creating Harmonious #Grays
1) Create two shapes and fill them with #424242 and #fafafa.
2) Insert a color fill layer above your two shapes.
3) Change that fill to your base color (#30c9e8).
4) Set the blending mode to overlay, and bring the opacity right down to between 5 and 40% (in the example below, it’s set at 40%).
5) Use the color picker and copy your new values.