Machine Shop, Oddities, Photography & Images

Monthly Image: CD Diffraction

Just to see how it worked, I engraved the Tek Circuit Computer scales on scrap CDs:

CNC 3018-Pro - front overview
CNC 3018-Pro – front overview

At first, I hadn’t correctly scaled the text paths, but the diffraction patterns caught my eye:

Tek CC on CD - bottom - unscaled text
Tek CC on CD – bottom – unscaled text

The illumination comes from two “daylight” T8 LED tubes in a shoplight fixture, running left-to-right, so it seems I held the camera rotated 1/4 turn in landscape mode. The pix look OK either way.

Bottom deck:

Tek CC on CD - bottom
Tek CC on CD – bottom

Middle deck:

Tek CC on CD - middle
Tek CC on CD – middle

Top deck, with the camera held portrait-style:

Tek CC on CD - top
Tek CC on CD – top

I’m a sucker for diffraction patterns …

The tiny engravings don’t photograph well, because they’re floating atop the transparent disc and the rainbow patterns from the data layer, but they still come out OK even when scaled to fit on a hard drive platter:

Tek CC - bottom deck - scaled to HD platter
Tek CC – bottom deck – scaled to HD platter

Looking good!

2 thoughts on “Monthly Image: CD Diffraction”

  1. You could reverse-engrave them on the aluminum/label/top side and see how they look from the bottom/read/other side.

    1. My one attempt with a pressed CD filled the shop with glitter as the friable lacquer shattered into a gazillion fragments. I should try a writeable CD / DVD to get, um, unicorns …

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