More pinholes, from the same pressing plant. Allied Record Company, LA (with Specialty Records Corp glass masters). They seem to have cornered the market on crummy disc coatings from around 1992, where this is the discovery when you pull out disc that failed to rip. pressing engraving: ARC *M4 S13. glass master: SRC**05 Click above to zoom and appreciate dots of light. pressing engraving: ARC *M2 S5, glass master: SRC-01 Notice above, the silk-screen printing hides the holes. The light comes through in pinholes in the unpainted track listing text. It's not scratches from the top, although illuminated from the top, some pin-sized losses of ink can also be seen. No handling that even scuffed the ink. These have spent the last 20 years in a basement that is 50-60F most of the year - my own salt mine. Also between "Sir" and "Stone": Stereo MC's - Connected (1992) (SRC+01 without plant etch) Pull it out, yep, same: To take these, I nearly burned my eyeballs out on a LED bulb (with the plastic orb removed to reveal bare LEDs), and then a LCD TV's diffuser sheet in front. Taped over the shiny stuff on the Lumia that reflected.
I bought a couple of ancient Oingo Boingo CDs last week. One had a few pinholes, plays and rips perfectly. I've had a similar experience with other ancient discs, scratches are far more damaging.
Sadly, some of my 20 year old silver CD-R's are beginning to die (the gold ones of the same age seem to be holding up much better). I have not found that to be the case though (thankfully) with any of my major label CD's, many of which are over 35 years old now.
I've found another defect or condition that has affected a few discs that were hard to read, this one still with some "no match" CueTools error tracks after 2 hours of ripping in paranoid mode: Instead of pinholes or bronzing, I will dub it "rainbowing". An oil-slick appearance seen through the top coat. A top coat thinner than a few wavelengths of light? And a new record for errors, on another flawed ARC/SRC disc, but without pinholes or other signs except minor handling -- 15 hours of ripping and re-reading (to only get three tracks bit-accurate but audible glitches fixed, with Cuetools DB also indicating other users have increasing problems at outer tracks):
It's called a Moire pattern. You're right: oil slicks give a similar pattern. It's quite common on CDs.
A moire pattern is from aliasing when undersampling an improperly filtered image. A screen door on a sharp camera or a plaid shirt on TV. Similar to the non-musical patterns that would appear in digital audio recording if there wasn't a lowpass anti-alias filter before the ADC converter. This, instead, is not correspondent to the etched groove, it is from the spin coated epoxy and top of reflective layer sputtered on disk. This and the oil slick effect is from quarter-wave cancellation. Light is reflected from the surface, but also enters the medium, reflects against a second plane, and bounces back out, causing destructive interference with the electromagnetic waves of the first reflection. The varying color is the from the varying frequencies being cancelled by the length of the second path. Audio in your listening room also can have analogous effects. It is is not seen on the playing side of the disk (the more common holographic rainbow associated with CDs). It is however a pattern to be discovered on several unpainted discs that barf with CRC errors, a distinct difference in the appearance vs others, among the other systematic faults mentioned in this thread. The 15 hour disk: It may be that such destructive interference between thin layers also causes such destruction in internal metal reflections or through the disc when the reflective playback layer is so transparent you can illuminate and read the track listing on the other side: Thanks, "Allied Record Company"
To prove there is a thin line between genius and madness, I'll let you make predictions about this experiment....
I have quite a few old ones that have stopped playing. My new Denon 1600 can play some of them but can’t play some new ones. Rat farts!
I've too noticed that many vintage CDs have pinholes, but I noticed them in the era they were made. Manufacturing processes had improved a lot by the '90s. But, I think all CDs will eventually die sooner or later. I suspect the gold ones will outlive all of us though. I recommend ripping and backing up at least two copies each of your treasured CDs.
I have a few discs like that too, I wonder what caused it. It does look like a thin film a few wavelengths thick like you said, maybe some mold release agent or some other accidental overapplication of some fluid in the manufacturing process? It looks like it’s on the label side of the reflective substrate but my guess is the enamel didn’t help the signal to noise enough for the transparent substrate, did it?
There's other discs I show earlier that have "water stains" in the reflective layer, some blotchy areas only slightly darker in the right illumination. I just squirted the CD with paint before the post. Rust-o-leum, I selected for its flowing surface, takes a long time to dry, but less work than setting up an acrylic enamel airbrush. "Dries tack free in 2-4 hours, to handle in 5-9 hours and fully dry in 24 hours". The expectation on a normally-assembled disc would be no change in the quality of the read from complete silk-screen coverage. It would be a curious "green pen" result if I actually got a different C1/C2 error count than the disc quality scan above. The hypothesis being that the black might absorb more of the penetrating laser light that would have been reflected around by the index of refraction gradient from backside epoxy coat to air.
I would call any interference pattern a Moire pattern, not just ones created by overlapping two patterns. But the CD pattern is caused by the lacquer coating the aluminium layer of the disc. It is common in many CDs. I noticed it is not seen often in those CDs produced by Sony in the 80s, but I may have to recheck.
The results of spray-painting the poor disc black, and re-testing at 24x: 1% more errors today. Possibly out-of balance? The blacked disc has an appearance of underlying silk-screen printing like the cover of Metallica black. C1: 236051-> 239157, 242387 C2: 8956-> 9027, 9534
I see only one hole there, and I presume that the big hole in the centre is not what you are talking about.
And man what a great soundtrack! I just checked mine, it's a standard Specialty manufacture. I'll check some of my ARC's. I have quite a few but I don't remember running into any issues.
Disc rot, anybody? I think I found the winner. There's more to be seen with backlight, but this is the most dramatic. It's a disc with black silk-screen. And the reflective coating is just gone, the printing showing through, the missing aluminum still sealed under the ink. Impressive that I even got the TOC off of it. Unplayed for probably 25 years. SonoPress USA, 1995: 20151-2
That pattern looks like an aluminum munching caterpillar got in there! I haven’t seen anything with a pattern like that yet, thanks for sharing.
That looks pretty bad, but I rarely encounter anything like that, even in shops that sell used CDs. None in my collection (5,000+) are like that.
You can also see this in DG classical CDs from WG, US or France. It's not uncommon for the waveforms to look slightly different between the three of them even though the CDs all came out roughly around the same time in the 80s. The late 80s/early 90s Impulse! Japan 32XD, US, and German CDs are also not digitally identical.
I'm just at hundreds, ripping CDs, comparing checksums online and reconstructing repairable errors with Cuetools, re-ripping with more intense settings, etc to get bit-perfect results that EAC alone might never complain about. About 5% have sample errors with simply 48x "burst" plus the drive's C2 error detection. About five I've had to leave with uncorrected errors; just one besides the "black hole" that audibly glitches on a song I still want. Good for also cataloging the nature of the disc defects that caused those misreads (that on a CD player might just be masked). Now into the continuous mix discs to rip as one FLAC image with embedded cue sheet. Cuetools/cueripper is clunky, but also pretty badass. About 25000 CD rips a day are reported to its online database along with error-correcting code.
It'd be appreciated if folks giving examples of disc imperfections could make it clear to this dumb reader whether the discs play or not. Although I can see/read about plenty of cosmetic imperfections I'm not sure which way the thread is leaning on the effect on playback. Cheers
