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9954tony
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Post subject: the "pressing" of laserdiscs Posted: 13 Sep 2020, 23:00 |
Serious fan |
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Joined: 12 Sep 2015, 05:57 Posts: 210 Location: United States Has thanked: 5 times Been thanked: 54 times
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some time ago, i read: An approximate figure is 25,000 pressings from a single stamper before it needs to be retired.What got me curious here, is: "What level of degradation in the stamper exists before retirement (if any)?" Here's a "loose" analogy: Let's say you have a rubber stamper to stamp "PAID" on invoices in some kind of office setting. Eventually, the rubber wears down and the stamper doesn't stamp the word "PAID" as well. Is 25,000 the amount of pressings before "any" degredation? Or is 25,000 the amount of of pressings before "acceptable" degredation? Sometimes i've heard people say, "(such and such) movie looks great!". Then i get a copy, and it doesn't look so great (picture noise). Did they have #1-100 off the stamper and i had #24,999?
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cplusplus
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Post subject: Re: the "pressing" of laserdiscs Posted: 14 Sep 2020, 00:34 |
Hardcore fan |
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Joined: 13 Aug 2018, 03:18 Posts: 1520 Has thanked: 449 times Been thanked: 588 times
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9954tony wrote: Is 25,000 the amount of pressings before "any" degredation? Or is 25,000 the amount of of pressings before "acceptable" degredation? Interesting question. I would think the latter. In either case, I don't think there would be any visual difference (in regards to playback). 9954tony wrote: Sometimes i've heard people say, "(such and such) movie looks great!". Then i get a copy, and it doesn't look so great (picture noise). Did they have #1-100 off the stamper and i had #24,999? As long as they are from the same master, the players involved and their adjustments will be the main factor. i.e. a LD-V2000 vs a CLD-D502 or even a CLD-97 vs a CLD-97 with the tilt servo improperly adjusted. 9954tony wrote: I guess that the 25000 if there is such a number was figured out with microscopes or other devices to read data and make sure its within the tolerance level. Yeah I think it was pretty much this. By the mid 1980's they had gotten this down to a very fine science.
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9954tony
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Post subject: Re: the "pressing" of laserdiscs Posted: 14 Sep 2020, 02:03 |
Serious fan |
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Joined: 12 Sep 2015, 05:57 Posts: 210 Location: United States Has thanked: 5 times Been thanked: 54 times
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I didn't make up the 25,000 figure, it was on the linked page: http://www.laserdiscarchive.co.uk/laser ... oduced.htmsignofzeta wrote: I don’t think your train of thought is correct... ...Your example of a rubber stamp doesn’t take into account gain adjustment The analogy was only with regard to the wearing of the mold/stamper. The mold/stamper wears out, otherwise they wouldn't need to change it after 25,000 uses. The fact that they change stamper/mold at all, indicates that there *is* a point at which the finished product would be noticeably degraded, they wouldn't waste money making more molds/stampers than they needed. My pondering was about that, and at what "acceptable" level they decided to set the limit, that's all. Signal strength (the gain adjustment) isn't the only parameter, or the one i was thinking about, it would be imperfections affecting the frequency output that i was thinking of. I'm also not the only one to have this thought: "Suspected causes of snow in freshly minted discs include: pressing discs with a worn or damaged stamper, pressing when the acrylic is not at the correct temperature, peeling the stamper and acrylic apart too soon or too late, metallization layer too thin, and contaminants in the production environment." from http://www.blam1.com/laserdisc/FAQ/FAQ_Hardware.htmHopefully, it is as all of you say, and the replacement happens well before any noticeable degradation.
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admin
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Post subject: Re: the "pressing" of laserdiscs Posted: 14 Sep 2020, 03:57 |
Site Admin |
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Joined: 07 Aug 2002, 23:37 Posts: 4551 Location: Tokyo Has thanked: 295 times Been thanked: 1147 times
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9954tony wrote: I didn't make up the 25,000 figure, it was on the linked page: http://www.laserdiscarchive.co.uk/laser ... oduced.htmsignofzeta wrote: I don’t think your train of thought is correct... ...Your example of a rubber stamp doesn’t take into account gain adjustment I read something similar for vinyl/records. The master is supposed to be used up to 50K discs but factories on a budget will push them to 60K or 70K. One reason why vintage Japanese records are still in demand: pure vinyl (no chemical mix in the 70's during the oil crisis to make them cheaper) and no overworn masters. On Pioneer mint marks, it's easy to see which master you got: XXXXXXX-A01-P YYYYYYYYY That's master #1. Late pressing rarely went up to #2. Julien
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