How to Use Colorable Glass, Colorable Stained Glass, and the Glassential Brush
Colorable Glass and Colorable Stained Glass let you change a glass block's color in place, without breaking and replacing it. The Glassential Brush is the tool that does the dyeing.
Getting the blocks
Craft Colorable Glass and Colorable Stained Glass the same way you would craft their vanilla counterparts, then place them where you want them. Colorable Glass Pane and Colorable Stained Glass Pane are the pane versions for windows and dividers.
Dyeing with the Glassential Brush
Hold the Glassential Brush and right-click a Colorable Glass block or pane. The brush cycles or applies a color depending on how the mod is configured. To set a specific color, combine the brush with a dye in a crafting grid, or right-click while holding the dye — check JEI/REI for the exact interaction your version uses. The block updates in place, so you can recolor an entire wall without tearing it down.
Why this matters
Colorable Stained Glass behaves like stained glass for light and visibility, so you can tint a window and still see through it. Colorable Glass is the clear variant that only takes on the tint you apply. This is ideal for builds where you want to fine-tune a color after the fact, or for map makers who need to change glass colors via commands or redstone.
Tip
Keep a stack of the brush in your hotbar while building windows — recoloring is faster than breaking and re-placing.