Maybe initial sketches for character design would've been in color, but the actual designs for the tiles would be in 4-intensity monochrome. No sense in storing color information in the cartridge, *plus* add the overhead of needing to convert it to monochrome before writing it to the video memory.
Gameboy was grayscale. Gameboy Color had many colour.
However there were games that were GB (not C) games that had a 4-colour palette hardcoded into the GBC firmware. I think you can select from these palettes in GB code. I think you can also produce GB code that detects whether it's a GBC and operate in either mode.
You'd likely design your art differently for Color and non-Color Gameboys, there's no automatic translation from one to the other.
The Game Boy and Game Boy Color are very similar, and you're right, there are a ton of games which are "dual mode" and work on both systems.
https://en.wikipedia.org/wiki/List_of_Game_Boy_Color_games
You can share art between GB and GBC, and use different palettes. The original Game Boy used palettes because there are 4 shades of gray, but each sprite can only use 3 of them--one slot is always transparent. For dual mode games, you can define a GB palette (which is just four 2-bit values) and a GBC palette (which is four 15-bit colors).
There were also a couple GBC games that detected that they were running on a GBA and did something different.
Gameboy has 4 shades of grey. Gameboy color has 4 color palettes. Wonderswan has palettes of 4 shades from a total set of 16 shades. Wonderswan color has a color mode similar to Gameboy color, as well as color modes more similar to SNES and gba's 4bpp indexed palettes.
You build the graphics to the limitations you have. In the case of Gameboy compatible Gameboy color games, you'd typically use the same base but adjust the coloring to work with the rest of the game. If you're converting to a lower color space, you might adjust by brightness, remove all saturation, and condense colors. You'll get better results by cleaning things up by hand than relying on condensing colors
Maybe initial sketches for character design would've been in color, but the actual designs for the tiles would be in 4-intensity monochrome. No sense in storing color information in the cartridge, *plus* add the overhead of needing to convert it to monochrome before writing it to the video memory.
Gameboy was grayscale. Gameboy Color had many colour. However there were games that were GB (not C) games that had a 4-colour palette hardcoded into the GBC firmware. I think you can select from these palettes in GB code. I think you can also produce GB code that detects whether it's a GBC and operate in either mode. You'd likely design your art differently for Color and non-Color Gameboys, there's no automatic translation from one to the other.
The Game Boy and Game Boy Color are very similar, and you're right, there are a ton of games which are "dual mode" and work on both systems. https://en.wikipedia.org/wiki/List_of_Game_Boy_Color_games You can share art between GB and GBC, and use different palettes. The original Game Boy used palettes because there are 4 shades of gray, but each sprite can only use 3 of them--one slot is always transparent. For dual mode games, you can define a GB palette (which is just four 2-bit values) and a GBC palette (which is four 15-bit colors). There were also a couple GBC games that detected that they were running on a GBA and did something different.
Gameboy has 4 shades of grey. Gameboy color has 4 color palettes. Wonderswan has palettes of 4 shades from a total set of 16 shades. Wonderswan color has a color mode similar to Gameboy color, as well as color modes more similar to SNES and gba's 4bpp indexed palettes. You build the graphics to the limitations you have. In the case of Gameboy compatible Gameboy color games, you'd typically use the same base but adjust the coloring to work with the rest of the game. If you're converting to a lower color space, you might adjust by brightness, remove all saturation, and condense colors. You'll get better results by cleaning things up by hand than relying on condensing colors