I’ve had some e-mail correspondence that suggests something about the Epson inkjet hardware and software: That Epson has, in my words, dumbed down the traditional error diffusion dither algorithm so that it can’t represent detail finer than 720 pixels per inch at 2880 DPI resolution, or finer than 360 pixels per inch at 1440 DPI… [Read More]
Archives for 2011
Focusing, part 1
If you’ve read the last four or five posts, it’s probably occurred to you that, in the new high resolution digital image, focusing is a challenge. Indeed; if you want to take full advantage of all the pixels that modern technology can give you, I think focusing is the most problematical operation in photography. It… [Read More]
Resampling – the mailbag
I got some perceptive comments about the resampling post, all from the same person. Here’s the first: For starters, two-thirds (not half) of the information in any color image from a Bayer-pattern sensor is fabricated. Half of the green and three-quarters each of the red and blue pixel values are made up. Absolutely true. My… [Read More]
Resampling
Resampling has a bad name among many photographers. Here’s a typical pronouncement, from here: “I am not going to address resampling here because it degrades an image and has little application in fine art photography. (Resampling is when Photoshop adds pixels to an image.)” Dodgy grammar aside, I strongly disagree. On the artistic level, I… [Read More]
Output antialiasing
Let’s review conventional sampling theory. We start with a continuous representation (the real world, as imaged by the lens), filter that to remove spectral components above half the sampling frequency, sample at evenly spaced infinitesimal points, digitize the results, and store them. To reconstruct the input we take the samples, recreate their values and locations,… [Read More]