Glyphs and glyph layers can be marked with color labels. Color labels do not affect the exported fonts but are used to organise glyphs during font development. They are useful tool combined with smart filters.
GlyphsApp use two different type of Label Colors:
Hold down Option and choose Set Layer Color to […] a layer color rather than a glyph color. Both glyph and layer colors will be displayed in the Info box. The glyph color is displayed on the left half, the layer color on the right half, which corresponds to the display of label colors in Font View.
Glyph Color is shared by All Layers
of a glyph, useful to mark glyph with same color accros All Masters.
Layer Color is assigned to a Single Layer, useful to mark glyph with different colors for Each Masters.
Here we will focus on Layer Color, to track progress of individual masters. An effective way to use Layer Color is to use them to assign development status to a layer. So, first step is to assign a dev status for each color.
For that you can use Label Key plugin (accessible in Glyphs from Window > Plugin Manager > Plugins). It show in a Palette Panel, color labels and the meaning you have assigned to them.
To configure it, check this documentation.
Here is a basic color workflow :
Red → To Do
Orange → First Draft
Brow → Second Draft
Yellow → Outline OK
Blue → Spacing Set
Magenta → Kerning Group Set
Purple → Anchors Set
Green → Ready
Now that you have your workflow set up, you can assign Layer Color according the development progress of your layers. This will take some effort at first, but quickly you will be able to assign them automatically during design process.