Dev Stack Source

Answer : If you want to convert hex to rgb you can use sscanf: <?php $hex = "#ff9900"; list($r, $g, $b) = sscanf($hex, "#%02x%02x%02x"); echo "$hex -> $r $g $b"; ?> Output: #ff9900 -> 255 153 0 Check out PHP's hexdec() and dechex() functions: http://php.net/manual/en/function.hexdec.php Example: $value = hexdec('ff'); // $value = 255 I made a function which also returns alpha if alpha is provided as a second parameter the code is below. The function function hexToRgb($hex, $alpha = false) { $hex = str_replace('#', '', $hex); $length = strlen($hex); $rgb['r'] = hexdec($length == 6 ? substr($hex, 0, 2) : ($length == 3 ? str_repeat(substr($hex, 0, 1), 2) : 0)); $rgb['g'] = hexdec($length == 6 ? substr($hex, 2, 2) : ($length == 3 ? str_repeat(substr($hex, 1, 1), 2) : 0)); $rgb['b'] = hexdec($length == 6 ? substr($hex, 4, 2) : ($length == 3 ? str_repeat(substr($hex, 2, 1)...

Answer : You probably want to use an image's convert method: import PIL.Image rgba_image = PIL.Image.open(path_to_image) rgb_image = rgba_image.convert('RGB') In case of numpy array, I use this solution: def rgba2rgb( rgba, background=(255,255,255) ): row, col, ch = rgba.shape if ch == 3: return rgba assert ch == 4, 'RGBA image has 4 channels.' rgb = np.zeros( (row, col, 3), dtype='float32' ) r, g, b, a = rgba[:,:,0], rgba[:,:,1], rgba[:,:,2], rgba[:,:,3] a = np.asarray( a, dtype='float32' ) / 255.0 R, G, B = background rgb[:,:,0] = r * a + (1.0 - a) * R rgb[:,:,1] = g * a + (1.0 - a) * G rgb[:,:,2] = b * a + (1.0 - a) * B return np.asarray( rgb, dtype='uint8' ) in which the argument rgba is a numpy array of type uint8 with 4 channels. The output is a numpy array with 3 channels of type uint8 . This array is easy to do I/O with library imageio using imread and imsave .

Answer : You will not get anything on the paper with a basic CMYK inkjet or laser printer. The CMYK color mixing is subtractive , meaning that it requires the base that is being colored to have all colors (i.e., White ) So that it can create color variation through subtraction: White - Cyan - Yellow = Green White - Yellow - Magenta = Red White - Cyan - Magenta = Blue White is represented as 0 cyan, 0 yellow, 0 magenta, and 0 black - effectively, 0 ink for a printer that simply has those four cartridges. This works great when you have white media, as "printing no ink" simply leaves the white exposed, but as you can imagine, this doesn't work for non-white media. If you don't have a base color to subtract from (i.e., Black ), then it doesn't matter what you subtract from it, you still have the color Black. As others are pointing out, there are special printers which can operate in the CMYW color space, or otherwise have a white ink or toner. These can ...