To put it simply, color is confusing and shape is everything!

The eye is usually what gets us first, we get stuck on the lower lid, or in the corner.

Well, that is because the eye is neither a line, as in pencil drawing.

Nor is it a a combination of shapes, as in paint-overs or wall projection.

It is a 3D object, as in 3D modeling.

But to get at it, you don’t want to use a 3D program, though you should be practicing your 3D modeling often.

You want to jump right in, and imagine that what you got is 3D.

Get your mid tones smeared over you canvas, and paint a sphere, but don’t you dare use color.

Then cover the sphere with eyelids, carefully pushing things back with black.

And getting things up in front with white, and even brighter edge.

Be the 3D, nananananananananana.

Don’t use color, you need to sculpt with just the grays.

Remember to see, to really see the shape, to fully go 3D, use a single color.

But wait there is more, you know how you add a new layer…

You have different blending modes, that are kind of fun to play with, but seem useless…

You can easily colorize your gray masterpiece, by creating a new layer on top of everything and setting it to color mode.

The color layer thinks in the HSL color mode, or HSL color theory, or HSL color algorithm, if you like.

It operates with the concepts of Hue, Saturation and Luminosity, just like the RGB mode operates on the concept of Red, Green, Blue.

Or kind of color, richness of color, and darkness/brightness of that color.

And guess what, it ignores the brightness and darkness or Luminosity, of the color you have currently selected...

And uses the darkness and brightness information, from your gray masterpiece beneath.

Ensuring that you cannot mess your 3D shape up, you can only color it - which is what you want!

Welcome to the curious world, of digital painting.