Error Correction during CD replay // Super Black Hole from Herbie's Audio Lab

I will try to find something.  For now read this:
https://en.wikipedia.org/wiki/Compact_disc

I use Walkman CD players and Walkman cassette players. One thing that Walkman CD player has in common with full size CD players is vulnerability to background scattered light from the CD laser. The background scattered light is a combination of visible red light circa 650-700 nm and invisible near infrared light circa 700-800 nm. The background light is presumed by the rather dumb photodetector to be real signal. The green pen and other counter measures can be employed to amileorate this ubiquitous problem.

I did buy Staedtler 350 Lumocolor marker in Green.
Funny thing, once I treated hybrid SACD of Grieg Piano Concerto with this marker, its SACD layer got busted: starting at track 2 it skips and stalls. CD layer is OK. This proves, I guess, that using green marker does have some effect.
Someone joked that Green is for the Spring/Summertime edge-painting, I shall try flat black tomorrow. 

Whoa! What! Never use green on Grieg! 😀 I’d be interested to hear what happens with flat black. I predict you will not like the sound. But if you use black on the inner edge I predict it will be OK. You can also try purple on the outer edge. A lot depends on what the label color of the disc is. What color is the Grieg SACD?

Problems with players reading CDs is typically the result of the CD itself and not the player. I have over 3500 CDs of varying brands, and many of my disks have been played back on a handful of different players.

I’ve never had a player in the price category of your Wadia though. At the moment, besides my Oppo UDP-205 which is a universal player, the only stand-alone red book CD player I have is an Emotiva ERC-3. One of things it does extremely well is "read" the disk, and in fact the ERC-3 differentiates itself from many other more expensive players because it spins the disk 3 to 4 times faster (1000 RPM) instead of a most players (300 RPM) and what that does is allow for re-reading of the same information.

However, if error correction algorithm is engaged then I also agree this is not "perfect" and is in fact a "best guess". In fact, this notion of "guessing" can be demonstrated when using a PC and the defacto standard ripping software, Exact Audio Copy. If a CD that cannot be read in a particular spot is ripped using "burst" mode, the data (albeit not all of it) can be copied/ripped. If you use a "secure’ mode in an attempt to "perfectly" read the data, often times this will not work (i.e. hang the software) or if it does work take an hour to complete instead of minutes.