Golden Ratio canvas sizes: Aviation Art. I will eventually put a 'summary' into the hints and tips once I have fully experienced the product.

The " canvas " is the visible area of the image. By default the size of the canvas coincides with the size of the layers. The Canvas Size… command opens the " Set Image Canvas Size " dialog that lets you enlarge or reduce the canvas size. You can, if you want, modify the size of the layers.Python - Tkinter Canvas - The Canvas is a rectangular area intended for drawing pictures or other complex layouts. You can place graphics, text, widgets or frames on a Canvas.