Create a custom colormap by dragging points on the RGB intensity curves.

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Copy your colormap

% Usage: ("C" is color matrix)
colormap(C/255); % in matlab

import matplotlib as mpl # in python
cm = mpl.colors.ListedColormap(C/255.0)
plt.imshow(..., cmap=cm) # for example

Or, copy a 256-color preset:

blues dawn
dusk fire
golds grays
greens ice
kryptonite purples
redblue reds
seashore teals