On Sale: GamesAssetsToolsTabletopComics
Indie game storeFree gamesFun gamesHorror games
Game developmentAssetsComics
SalesBundles
Jobs
Tags

Each shade counts as another color but you're allowed to use them, granting that it's going to increase your color count and therefore decrease the color score.

In the ruleset it indicates 'The same color with different alpha channels is not considered separate colors.', isnt grey technically black but with a different alpha channel ?

(+1)

Nope. It's basically referring to the hex code you use when everything is opaque. Adding transparency doesn't change the hex code. 

Deleted 329 days ago

If you created a sprite using only black and put it on a background of white, using an alpha channel would enable you to create a full grayscale sprite with only two colors and an alpha, which is technically in line with the stated rules, but goes against the spirit of the rules. This was clarified in another post. Using sprites to get multiple shades in this way would be considered using multiple colors.