Summarized: In this entry, the focus is on colorizing backgrounds to make sprites shine. Coloring backgrounds involves additional work like editing graphics and adjusting level layouts. The process of applying BG attributes depends on the game type. A routine is needed to print the background, and custom attributes can be added by fetching values from a BG Map attributes table stored in RAM. Editing graphics is necessary to adapt to new palettes. Maintaining a 1:1 relation between tiles and attributes is important. Each game requires investigation on how to store level maps. The tutorial provides a general idea of what to do. The next entry will cover implementing effects like fade-ins and fade-outs.
https://toruzz.com/blog/how-to-colorize-gb-games-04/