TRMNL e-ink screens show images in shades of gray. Originally, only black and white were supported, but firmware upgrades have unlocked the ability to display 4 shades on both first-party and BYOD hardware. TRMNL X will display 16 shades, and some BYOD screens even go up to 256 grays.
Bigger palettes looks nicer, and are generally preferable. They allow the jaggy edges of fonts to be anti-aliased into smooth curves. More levels of information hierarchy can be represented. And of course, photos and screenshots look closer to their originals.
These advantages come with some tradeoffs. Here are some things to consider when deciding what color palette to use.
Smaller Palette (e.g. Black & White)
Pro: Smaller file size, which is quicker to download, prolonging battery life
Pro: Faster transitions between screens
Con: Simpler, less contrasty images
Larger Palette (e.g. 4 grays, 16 grays)
Pro: More appealing images
Con: Larger file size, which takes longer to download, shortening battery life
Con: Slower, more noticeable transitions between screens
Changing the Palette
The preferred color palette can be adjusted per device, and also per playlist item for ultimate control. The change will take place the next time the plugin is refreshed.
For example, you might set the device to B&W for the highest performance most of the time, but override it to 4 shades of gray so your family photo looks its best.
To change the default color palette for the device, go to device settings and select "Color Palette".
To change the specific color palette for a playlist item, go to the Playlist, click "Adjust Schedule", and select a new palette in the dialog.
