Take background and foreground colors and a step count. Generates color scale based on different foreground color transparency steps over the background. Example: https://pasteboard.co/IKu4Sqw.png

transparency_scale.py

from Tkinter import *

def ablend(a, fg, bg):
    return ((1-a)*fg[0]+a*bg[0],
            (1-a)*fg[1]+a*bg[1],
            (1-a)*fg[2]+a*bg[2])

root = Tk()
num=8.0

fg=(0, 188, 212)
bg=(18,21,25)

for i in range(int(num)+1):
  col = ablend(i/num, fg, bg)
  e = Label(root, text=" "*70, background='#%02x%02x%02x' % col)
  print('#%02x%02x%02x' % col)
  e.grid(row=i)

root.mainloop()