For colors you should use this:
# Colors:
#
# red
# magenta orange
# 11 12 13 14 15 16
# 46 21
# 45 22
# blue 44 23 yellow
# 43 24
# 42 25
# 41 26
# 36 35 34 33 32 31
# cyan yellow-green
# green
#
# Special colors:
# 51 gray
# 52 brown 1
# 53 brown 2
#
# For a new metric_info you have to choose a color. No more hex-codes are needed!
# Instead you can choose a number of the above color ring and a letter 'a' or 'b
# where 'a' represents the basic color and 'b' is a nuance/shading of the basic color.
# Both number and letter must be declared!
#
# Example:
# "color" : "23/a" (basic color yellow)
# "color" : "23/b" (nuance of color yellow)
#
# As an alternative you can call indexed_color with a color index and the maximum
# number of colors you will need to generate a color. This function tries to return
# high contrast colors for "close" indices, so the colors of idx 1 and idx 2 may
# have stronger contrast than the colors at idx 3 and idx 10.
# retrieve an indexed color.
# param idx: the color index
# param total: the total number of colors needed in one graph.