processing images to look like halftone print

I have always liked old prints that look like they are made up of many small dots. This process / look is called halftone.
Here is an example of a black and white halftone print of an old Barbarella poster. (click on the right black and white images below to see what i’m talking about)

I made a python script that sort of replicates this look, using PIL. You can grab my halftone script here.
You can create dotted images in black and white or colour. You can have white dots on a black background, or black dots on a white background. So essentially a positive or negative method of dotting. The script gets some cool results, but it is quite slow, especially when you have a smaller dot size or larger resolution source files. As it builds a new image dot by dot, the more dots the more time it takes.

Here are some of my tests. Click on the images for full effect: please note they are obviously not from photos i have taken myself, and the sources and credits are unknown.

From commandline:

python pathToLB_halftone_v1.0.py fileOrFolderToSourceFrom args

or of course, you can alias it to ‘dot’ or whatever you like.

FLAGS:

-s –squareSize Sets the number of pixels allocated for each dot shape. Eg: 6 = more small dots 16 = fewer larger dots

-c –colours Sets the script to colour mode.

-f –fileType Sets the filetype for new files created. Supported types are: [ "jpeg", "tiff", "gif", "png" ]

-n –negative Sets the script to negative mode (being black dots on a white background) rather than the default, (white dots on a black background).

The python script i have made produces image results very similar to half tone -I guess the only difference is the dots are displayed in line with each other rather than in a zigzag pattern.

I would love to use either this script or my pixelize script to process some of my animation, for a stylized effect. Even animate the dot size over time perhaps? I guess that could be another idea…

Further info on halftone.