One of the issues I’m having to confront in the autohalftoning work has come up before in my image-processing programming, but I’ve always sidestepped it. When I write an image-manipulation program, I try to parameterize all of the options, rather than change the code to invoke them. It makes it a lot easier to go… [Read More]

In addition to kernel size and construction, you can also get useful effects by making the kernel sum to numbers slightly larger than one. This means that the kernel is not strictly a highpass filter, but will preserve some low frequency information. You don’t want much; multiplying the center element of a fence kernel by… [Read More]

I didn’t have any writing to do yesterday, since the blog was given over to prewritten April Foolery, so I messed around with convolution kernels. I came up with a class that seems to give interesting effects. Kernels in this class, which I’m calling “fence” kernels, are square with odd numbers of rows and columns…. [Read More]

Before I get started with some of what you can do with autohalftoning, I need to say a few words about workflow. In most digital photography, you do all your creative work on the file at its original resolution, and resize and sharpen just before printing. By following that procedure, you are prepared to make… [Read More]