I do not have an old version of git to verify that the colors other than red, blue and green are supported.
Although, one thing I noticed even with the recent versions of git (like 1.7.10 I used) is that colors other than red, green and blue need to be within parentheses (). For red, green and blue, the parentheses are optional.
So give this a try:
git log --pretty=format:"%Credred%Creset %Cgreengreen%Creset %C(Yellow)yellow%Creset %Cblueblue%Creset %C(magenta)magenta%Creset %C(cyan)cyan%Creset %C(white)white%Creset"
The list of colors I’m aware of at least are:
normal
black
red
green
yellow
blue
magenta
cyan
white
It can be combined with one of these attributes:
bold
dim
ul
blink
reverse
italic
strike
bright # (Git 2.26, Q1 2020, example: brightred)
If you’re trying to change colors using .gitconfig you should be able to specify two colors – foreground and background and you can combine it with an attribute.