The Image Module

im.convert(mode) ⇒ image

Converts an image to another mode, and returns the new image.

When converting from a palette image, this translates pixels through the palette. If mode is omitted, a mode is chosen so that all information in the image and the palette can be represented without a palette.

When converting from a colour image to black and white, the library uses the ITU-R 601-2 luma transform:

    L = R * 299/1000 + G * 587/1000 + B * 114/1000

When converting to a bilevel image (mode “1”), the source image is first converted to black and white. Resulting values larger than 127 are then set to white, and the image is dithered. To use other thresholds, use the point method. To disable dithering, use the dither= option (see below).

im.convert(“P”, **options) ⇒ image

Same, but provides better control when converting an “RGB” image to an 8-bit palette image. Available options are:

dither=. Controls dithering. The default is FLOYDSTEINBERG, which distributes errors to neighboring pixels. To disable dithering, use NONE.

palette=. Controls palette generation. The default is WEB, which is the standard 216-color “web palette”. To use an optimized palette, use ADAPTIVE.

colors=. Controls the number of colors used for the palette when palette is ADAPTIVE. Defaults to the maximum value, 256 colors.

im.convert(mode, matrix) ⇒ image

Converts an “RGB” image to “L” or “RGB” using a conversion matrix. The matrix is a 4- or 16-tuple.

The following example converts an RGB image (linearly calibrated according to ITU-R 709, using the D65 luminant) to the CIE XYZ colour space:

rgb2xyz = (
    0.412453, 0.357580, 0.180423, 0,
    0.212671, 0.715160, 0.072169, 0,
    0.019334, 0.119193, 0.950227, 0 )
out = im.convert("RGB", rgb2xyz)