ppint.Got you!,we're now both reading from the same page;).Interesting,i have seen them being made in a clean-room environment,to prevent/limit contamination.I wonder if that's what happened to PDO Discs(commonly affected with Disc-Rot),or whether perhaps that may have been due to the materials used?.Anyhow, i now know that it doesn't matter which way Disc's are positioned prior to "writing",so would expect to see more "reverse" matrices,thanks for that.
g'78s: aha! (to risk an xxxxian obscenity ;-) ) - iswym. "the answer's the same, but the question's different", to re-coin a phrase. cds're multi-layer (tablettything's trying to insist on "multi-dimensional" - i wonder what s/he/it's trying to tell me°) - and it doesn't really matter which way up the transparent plastic base is, before the aluminium?alloy? "silver" layer (& the colour layer) is laid down/bonded on/whatever (even stapled on could/might work, so long as the staples don't protrude upwards (from the obverse, label side) too much, nor from the reverse (the played/read side) too much - if at all - and so don't interfere with the disc carriage mechanism, and definitely don't interfere with the reading lens &/or its transport mechanism - staples, whate'er they be made of, nor insets designed to keep them out of the way.°°,°°°
°°° - and any liquid, or gas, or substantial solid, opaque foreign matter can intrude between the transparent surface and the very thin layer readable metal, then difficulties playing back the recorded data/digitaliesd music will arise, sooner or later, whether through introducing too great (= an unbridgeable) physical gap in the continuity of the data; chemical degradation of the "silver" metallic thin layer, and hence of the data; the introduction of an inconsistently variable refractive interface in the path of the reading laser - or, the destruction of the material the staples're made of, and hence their integrity. . .
(°° - quite what the tolerances may be for all these, variously, i've never bothered to look up: but they'll be somewhere on the wibblywobblywonderful, i've little doubt.)
Thanks very much for the info ppint.I fear however that we might have got our wires crossed somewhat (probably my fault in the descriptive;).Imagine standing above the Disc and lowering it onto the spindle at plant,nboldock's image is correct in that"Disctronics" reads as normal,but on my Disc"Distronics" is backwards,implying that the Disc has been put onto the spindle upside-down before pressing,and the question was if that really matters,in this case it obviously dosen't,as the play side has still been "written" to this Disc fine.(i should perhaps add that the play side on my Disc is still as normal,i.e the reverse of the printed side)."you see don't i" ;)
g'78s: er, "yes, and no." (not excessively helpful, but accurate.)
- printing onto the reverse surface is theoretically & technically possible, but inadvisable - the ink(s)(dyes, pigments) could easily obscure part of the playing track, etc.); so i doubt music cd "presses" are set up to do it at all;
- information including the matrix-equivalent number, frequently the "pressing" company id, and usually the music corpses' cat#, sometimes also the bar-code number or some derivative of it, etc, is almost always included by the same process and at the same time as that placing the digitally-encoded audio track on/in the cd layer: this cannot be altered except by production of a new master-pressing-plate-equivalent, as it's sealed into the cd thus, as the encoded data "silver" layer is produced.
- physical impression into the reverse surface as the disc is "pressed" is possible, and occasionally seems to've been deliberately achieved to add some further information; well within the radius of the "label" circle on the obverse of the disc - usually (more-or-less) in or within the circle of the matrix-equivalent no./code, etc.
I've uploaded a scan of the centre of the disc to show a "reversed" matrix,i.e the printed side of the Disc is on the other side,which begs the question,if,when at the pressing plant,can both sides of the blank media be "written" on?,or am i just being daft ;)