Sorry but this is just your example being horribly misgenerated/some gamma being applied twice, maybe even thrice. Here is what I generated: sRGB: https://i.im

Sorry but this is just your example being horribly misgenerated/some gamma being applied twice, maybe even thrice. Here is what I generated: sRGB: https://i.imgur.com/dbn3TM6.png https://i.imgur.com/dbn3TM6.png Lab (linear): https://i.imgur.com/dCXzbF3.png https://i.imgur.com/dCXzbF3.png Please download the images and view in a proper image viewer. For some reason at least on my Windows machine Google Chrome adds horrible color banding to both images. This is my code: import imageio import numpy as np import colour quantize_with_dither = lambda im: np.clip(im * (2**8-1) + np.random.uniform(size=im.shape), 0, 2**8-1).astype(np.uint8) srgb_black = [0, 0, 0] srgb_white = [1, 1, 1] srgb_grad = np.linspace(srgb_black, srgb_white, 500) * np.ones((200, 1, 3)) imageio.imwrite("srgb.tif", quantize_with_dither(srgb_grad)) lab_black = colour.XYZ_to_Lab(colour.sRGB_to_XYZ(srgb_black)) lab_white = colour.XYZ_to_Lab(colour.sRGB_to_XYZ(srgb_white)) lab_grad = np.linspace(lab_black, lab_white, 500) * np.ones((200, 1, 3)) lab_grad_in_srgb = colour.XYZ_to_sRGB(colour.Lab_to_XYZ(lab_grad)) imageio.imwrite("lab.tif", quantize_with_dither(lab_grad_in_srgb)) I didn't trust imageio's correct handling of gamma/colorspaces so I just wrote out the raw sRGB coefficients as 8-bit TIFF and used imagemagick to convert to PNG, telling it that the input is in sRGB: magick convert lab.tif -set colorspace sRGB -depth 8 lab.png magick convert srgb.tif -set colorspace sRGB -depth 8 srgb.png