Change color scheme on Samsung Galaxy S4 running Lollipop 5.0.1
The Touchwiz Lollipop skin has a limited number of color schemes available to use that can be accessed through Developer Options. I am not entirely sure what the purpose for them really is since they merely drain away colors and mute everything. Anyway, the new way to access Developer Options is to go to the About Device under the More tab in your settings and scroll down to Build Number. Keep tapping Build Number until the Developer Options are turned on (you will see a message below where you are tapping). In the Developer Options now under the More tab, scroll way down to Simulate color space. You'll 4 options including grayscale/monochromatic.

In my opinion, these options suck. I've had my S4 for 2 years. Maybe it's time to pick up a phone from another manufacturer.