It looks like webcolors will allow you to do this:

rgb_to_name(rgb_triplet, spec='css3')

Convert a 3-tuple of integers, suitable for use in an rgb() color triplet, to its corresponding normalized color name, if any such name exists; valid values are html4, css2, css21 and css3, and the default is css3.

Example:

>>> rgb_to_name((0, 0, 0))'black'

it is vice-versa-able:

>>> name_to_rgb('navy')(0, 0, 128)

To find the closest colour name:

However webcolors raises an exception if it can't find a match for the requested colour. I've written a little fix that delivers the closest matching name for the requested RGB colour. It matches by Euclidian distance in the RGB space.

import webcolorsdef closest_colour(requested_colour):    min_colours = {}    for key, name in webcolors.css3_hex_to_names.items():        r_c, g_c, b_c = webcolors.hex_to_rgb(key)        rd = (r_c - requested_colour[0]) ** 2        gd = (g_c - requested_colour[1]) ** 2        bd = (b_c - requested_colour[2]) ** 2        min_colours[(rd + gd + bd)] = name    return min_colours[min(min_colours.keys())]def get_colour_name(requested_colour):    try:        closest_name = actual_name = webcolors.rgb_to_name(requested_colour)    except ValueError:        closest_name = closest_colour(requested_colour)        actual_name = None    return actual_name, closest_namerequested_colour = (119, 172, 152)actual_name, closest_name = get_colour_name(requested_colour)print "Actual colour name:", actual_name, ", closest colour name:", closest_name

Output:

Actual colour name: None , closest colour name: cadetblue

There is a program called pynche which can change RGB to colour name in English for Python.

You can try to use the method ColorDB.nearest() in ColorDB.py which can do what you want.

You can find more information about this method here : ColorDB Pynche

For those who, like me, want a more familiar colour name, you can use the CSS 2.1 colour names, also provided by webcolors:

• aqua: #00ffff
• black: #000000
• blue: #0000ff
• fuchsia: #ff00ff
• green: #008000
• grey: #808080
• lime: #00ff00
• maroon: #800000
• navy: #000080
• olive: #808000
• purple: #800080
• red: #ff0000
• silver: #c0c0c0
• teal: #008080
• white: #ffffff
• yellow: #ffff00
• orange: #ffa500

Just use fraxel's excellent answer and code for getting the closest colour, adapted to CSS 2.1:

def get_colour_name(rgb_triplet):    min_colours = {}    for key, name in webcolors.css21_hex_to_names.items():        r_c, g_c, b_c = webcolors.hex_to_rgb(key)        rd = (r_c - rgb_triplet[0]) ** 2        gd = (g_c - rgb_triplet[1]) ** 2        bd = (b_c - rgb_triplet[2]) ** 2        min_colours[(rd + gd + bd)] = name    return min_colours[min(min_colours.keys())]