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A Little Slice of a Big Spiral

This Illus­tra­tor file was too big and com­plex to be ren­dered into a high-res­o­lu­tion raster by either Illus­tra­tor or Pho­to­shop. Here GIM­P’s Ghost­script inter­preter was brought in for the job, which it did hand­i­ly in less than an hour. Illus­tra­tor flat-out refused to export the 500,000-endpoint vec­tor file at the res­o­lu­tion I need­ed, and Pho­to­shop kept one of my eight proces­sor cores work­ing at 100% for more than two days before I gave up and gave Pho­to­shop the ol’ «Force Quit».

Spiral's Edge

Now what I have is a three-and-a-half giga­byte grayscale spi­ral. You know that fan­cy 12-megapix­el cam­era you’ve been want­i­ng to buy? I could fit almost 300 of the images it makes into this one file. Are we hav­ing fun yet?

This is not yet sat­is­fac­to­ry. Actu­al­ly, it’s just the begin­ning of the process. This is where the real work begins. I go into the file in Pho­to­shop with my Wacom tablet, select a dis­tor­tion tool, and draw over the lines. As my hand fol­lows the lines, my hand moves cre­at­ing vari­a­tions as though I had drawn the lines myself. In a sense I am draw­ing the lines, using my pat­tern as a tem­plate. The tem­plate moves and cre­ates a ragged, irreg­u­lar pat­tern that fol­lows close­ly the orig­i­nal spiral.

This pat­tern is what I use to turn images into lines. The com­put­er uses a thresh­old func­tion to take an image and this pat­tern, mul­ti­ply their val­ues, and give me either total black or total white. The end result of using a pat­tern like mine where the val­ues shift grad­u­al­ly from dark to light and back is that where the image I’m work­ing with is dark, I end up with thick­er lines. Where the image is light, I have thin­ner lines. And that makes a pat­tern of lines that cre­ates an illu­sion of a gray tone.

ImageIn order to demon­strate what I can do with this pat­tern, I’ve used a pho­to­graph of myself. In this exam­ple, I’ve only over­lain the pat­tern on the left side of the image, leav­ing the right side as it was orig­i­nal­ly. If my expla­na­tion was con­fus­ing, the exam­ple should make it intu­itive­ly clear what has hap­pened, even if the why or how remains in doubt. The lines in the spi­ral pat­tern grow thick­er to rep­re­sent dark areas of the pho­to, and become thin for the light areas.

This is basi­cal­ly how the files for my prints are made. I work this process once for each of the col­ors in the palette I’m using, then put all the col­ors togeth­er and have what still appears to be a pho­to­graph, but all made of irreg­u­lar, hand-drawn lines. The final prints are exposed on metal­lic pho­to­graph­ic paper with a micro­proces­sor-con­trolled laser.

The pur­pose of it all is to bring the human hand into the process of mak­ing pho­to­graph­ic prints. The images are all line and tex­ture up close, but if you step back a few feet the lines dis­ap­pear and the image comes out. Also, inter­fer­ence pat­terns become very vis­i­ble where the pat­terns lay over one anoth­er, which is all over a piece where the col­ors have been split apart pho­to­graph­i­cal­ly. The image comes alive in a way that the orig­i­nal pho­to­graph could not, and which a pure­ly hand-ren­dered illus­tra­tion would not.

See The Face?

3 Replies to “A Little Slice of a Big Spiral”

  1. Great job on the spi­ral halftone!

    Great job on the spi­ral halftone! I’m prob­a­bly one of the few peo­ple who can tru­ly appre­ci­ate the dif­fi­cul­ty and the cool­ness of the graph­ic you created.;topic=1025.0;attach=319;image

    Your sketch­es are a fine exam­ple of a type of halftone i’d like to write soft­ware to cre­ate. I’ve imag­ined that a pho­to could be opened in pho­to­shop and almost like a col­or­ing book, areas of the image could be marked to use line halftones, hatch, spi­ral, text or any defin­able shape. Todays com­put­ers allow such crazy pro­cess­ing to be eas­i­ly pos­si­ble. Col­or vari­a­tions could even be con­vert­ed to tex­ture variations.




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