5 ms·
Maybe I'm missing something but how is the image so clear? CDs don't have a mirror like surface, they reflect light in unusual ways
by bentpins 6y ago
Maybe I'm missing something but how is the image so clear? CDs don't have a mirror like surface, they reflect light in unusual ways
- formerly_proven 6y agoUse a pressed CD (which are good mirrors at this angle), not a blank CD (which are tinted).
- jeffbee 6y agoI just pointed a CD at my face and it's pretty much a mirror. What unusual reflection did you expect?
- bentpins 6y agoSome rainbow diffraction I guess. It has been a long time since I've used a CD https://www.google.com/search?tbm=isch&q=cd https://www.google.com/search?tbm=isch&q=cd
- tedunangst 6y agoReal CDs don't look like clip art CDs. 90% of the images for "mirror" don't have reflections either.
- the_svd_doctor 6y agoI also don't really get it. Looks too clear and sharp for a CD reflection.
- TaylorAlexander 6y agoWell I noticed it's a CD-RW which is a peculiar device, so maybe it doesn't reflect the same as normal CDs.
- simias 6y agoThe rather shallow angle probably helps a lot. On top of that the camera probably has some form of auto white balance which will counteract the tint the CD will give to the image. Here's a quick proof of concept using a random CD and my phone's camera: https://svkt.org/~simias/up/20200914-000627_psx-cd-reflection.jpeg https://svkt.org/~simias/up/20200914-000627_psx-cd-reflectio... Note that the color of the reflection is not much different from a normal picture (visible at the bottom). For added difficulty I used an original PlayStation disc, that's dyed black: https://svkt.org/~simias/up/20200914-000836_psx-cd.jpeg https://svkt.org/~simias/up/20200914-000836_psx-cd.jpeg
- jeffbee 6y agoIt's very HN that we've been trolled into debating the irrefutable, widely-known, totally obvious fact that a CD reflects light.
- Xavdidtheshadow 6y agoEverything reflects light, but not everything reflects it clear enough to read documents through. I haven't held a CD in ages, so it it's possible that folks don't remember exactly how reflective they are. ¯\_(ツ)_/¯
- bentpins 6y agoDidn't mean to come across as a troll, this is how I remember CDs, with rainbow diffraction. https://www.google.com/search?tbm=isch&q=cd https://www.google.com/search?tbm=isch&q=cd
- simias 6y agoI think at such shallow angles it's the plastic surface that becomes reflective, not the metal layer with the pits and grooves. Hence the lack of diffraction (and hence why it works with my black PSX disc).
- kevin_thibedeau 6y ago
- deleted 6y ago[deleted]
- djmips 6y agoI think you probably haven't played around with CDs more than just to play them.