Re: filmscanners: RE: cd storage
BTW, one time I had a CDR that had to be destroyed (it had client proprietary info), so I set about seeing just how destructible CDRs are. The answer is that they are very fragile -- if anything scratches through the lacquer and metallic top, the whole top will flake off quite readily. The main areas of adhesion are at the hub and rim where there is no dye layer -- the adhesion of the metallic film to the dye is not strong at all. Try 2 sec in the microwave - especially with ots of CDR's it is quite beautiful. Bill Ross
Re: filmscanners: RE: cd storage
I have a silly question -- why not use the unique ID number that already appears in the hub area of most quality CDRs? It has the advantage that no further handling of the CD is required, and it is readable through the clear window of CD envelopes, jewel cases, or most other holders. Yeah, I know the ID is arcane (one example being C3127DL0911916HS) but it IS unique, which is all that's needed. Compared to the proposals of scratching a number in the hub area (what happens to the shavings?), applying a label then trying to peel it off, and so on, using the ID that's already there seems too easy. BTW, one time I had a CDR that had to be destroyed (it had client proprietary info), so I set about seeing just how destructible CDRs are. The answer is that they are very fragile -- if anything scratches through the lacquer and metallic top, the whole top will flake off quite readily. The main areas of adhesion are at the hub and rim where there is no dye layer -- the adhesion of the metallic film to the dye is not strong at all. --Dana -- From: Arthur Entlich [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: Re: filmscanners: RE: cd storage Date: Monday, December 11, 2000 3:07 AM The adhesives in most CD label systems are no water soluble, so you will have a mess if you attempt to soak them off, since only the paper will rub off, leaving gooey adhesive behind. I have, on occasion, removed a label and repositioned or replaced it. It takes careful even peeling. Unfortunately, these days, the darn labels cost more than the blank CD-Rs, which makes no sense at all, in terms of cost of production. In terms of what will most influence the longevity of these disks, I don't think anyone really knows yet. The products are all so new and untested that it is anyone's guess. Art Alan Tyson wrote: Ah! I've never tried it, so I didn't know that. My labels using a Neato kit have always been well centred. In that case, if our drives won't read the disk because it wobbles, we should write another and try again (not a huge expenditure), or buy cheaper labels with worse adhesive. Maybe soaking in water to assist peeling of misplaced labels, followed by slow gentle drying, wouldn't do any harm. Has anyone tried it? Alan T
RE: filmscanners: RE: cd storage
They are still working on a lot of the testing right now. What they gave us was based on what testing they have done so far. A lot of the long term aging stuff is still underway. What they had done was a lot of testing for disaster recovery - flooding, fire etc. I saw the graphs for CD's without labels and with, and the error introduced is quite significant. Though when new, may still be easily read (or not, in some cases). However, when this was added to some of the aging work they had already done, which show an increase in errors over time, especially if not stored in ideal conditions, then the label introduced error becomes significant. But we aren't generally talking a year or two (unless, you freeze your CD's in winter, let them toast in summer and get damp in the fall!). Say over ten years, a CD with no label might work fine. The much greater error caused by a label might push it over the edge and it won't read. Plus the adhesive may be affecting things. That top seal is, I believe, microns thick, and the foil is directly under there. They are involved in aging testing as I said, archival storage and the effect of temperature, humidity, chemicals, etc as well as comparing different types of dye and foil, and also doing a lot of work on measuring read errors and what causes them. They were sharing their data to date in a general way (this was a workshop on preservation of modern information carrier - optical and magnetic media), mainly where certain areas of work were basically complete. They were also giving guidelines base on their current reading of work still in progress. If I didn't post it here, I can post their basic guidelines for long term storage/archiving of CD's, based on their current knowledge - and they are heading towards 100 years at least for CD's (good quality and certain types of foil/dye) kept under these conditions. I think their work will be published at some point. Keep an eye on www.pch.gc.ca/cci-icc and/or hunt around to see what's there in their publications etc. Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Alan Tyson Sent: December 8, 2000 9:10 PM To: [EMAIL PROTECTED] Subject: Re: filmscanners: RE: cd storage Tim, You could always peel off the label and try again, if a disk doesn't read correctly. Surely an imbalance will show immediately. Everyone should test their CD-Rs after writing them, preferably in another drive. That 's a different issue from the longevity of the data. Have your conservation scientists any published work with real data, to which I could refer, or are they just guessing, based on their knowledge of the technologies involved, as I am? We all need this information to keep our lovely images pristine for our grandchildren, but I have the uncomfortable feeling that everyone's guessing, and no-one knows. We need some references to the scientific literature, don't we? Has anyone got a tame information scientist who'll find out the real state of the art for us? Alan T - Original Message - From: Tim Atherton [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, December 09, 2000 2:46 AM Subject: RE: filmscanners: RE: cd storage The info I had from the conservation scientists who are researching CD longevity and archival storage was; No sticky labels of any kind (they both unbalance and lead to read and write errors, even round ones
Re: filmscanners: RE: cd storage
Tim Atherton writes ... They are still working on a lot of the testing right now. What they gave us was based on what testing they have done so far. A lot of the long term aging stuff is still underway. What they had done was a lot of testing for disaster recovery - flooding, fire etc. ... I began this thread with a conversation I had with a Plextor tech support person, with respect to felt tip pens labelling totally blank Cds. I have no idea what insired him to pass on the possible fact that a "sharpee" might cause problems with the data ... but the point is we depend on Cds for archiving data. If it turns out that 10years down the road this person's speculation was indeed fact ... then I did the right thing by subsequently adapting to putting an ID# in the inside spindle area, only for keeping that CD in the corrrect jewel case which properly ID'd the data . shAf:o)
RE: filmscanners: RE: cd storage
Why don't I just pass on the notes and info I marked as being important for me after I did this workshop (which I think has already been posted once here...) :) Remeber it was a practical affair, for people using and storing images on optical and magnetic media. Archivists, photographers, Government info systems people, film makers etc. The advice was based on the current knowledge from people who are working in the filed, conversing with colleagues worldwide, and actively involved and testing themselves. This testing is not yet complete, but they have already carried out testing for disaster recovery (eg soaking CD's, heat damage, freezing etc etc). Most of the info is from the workshop notes, but some is based on info presented about their current testing for archival life of media, accelerated aging, etc etc and so bear in mind I may have made my own mistakes in transcribing this: Here is some info I posted on another list, based on a recent workshop I went on. This was on the preservation of modern information carriers (optical and magnetic media) run by two conservation scientists from the Canadian Conservation Institute: But basically, while testing is still being done, the following generally hold true; Best quality dyes and metallic layer in the disk - gold and phthalocyanine eg Kodak Gold Ultima and one or two other brands. Some are also marketed as "archival" this may not mean anything more, just marketed as such. Though some makers may be making the protective top lacquer layer of toughened material to resist scratching. Generally, you get what you pay for - better quality control, disks that are properly balanced (+ less read error) etc. Keep in reasonably low humidity and temperature. 10 to 20c is good (not below -10c) and RH 20-50% (not lower than 10%) No great cycling in either temperature or humidity, so constant. Keep in the jewel case( polystyrene, polypropylene or polycarbonate), on edge, no inserts if possible (not acid free). No labels etc (label and glue can cause damage, and labels, even circular, increased read errors dramatically). Non solvent marker if necessary on the case, and if on disk, only on the very inner circle where the serial number is. Store out of light - ie in the dark. Don't scratch them! Also, how they are burned also makes a big difference. Higher speed burning/write can lead to more errors. So 1 or 2x write is often better. Burn to ISO 9660 or whatever it is. In fact one of the biggest areas with longevity apart from the above was error level on the recording side, which depended on a number of factors and got very complicated. Depending on your burning software, running the test disk option actually tests it AFTER burning, to let you know how much error there was (there is always some error). Also, over time, CD burners deteriorate mechanically, introducing more error. So, that's a quick overview. If there is stuff I forgot, I'll pass it along They are still testing accelerated aging in different conditions, but I think they were figuring at least 50-100 years following these type of guidelines. Of course other factors come into effect such as machines to read them and so on, but that is a slightly different topic. Finally, make one for use and one or two for backup, stored separately - fire, flood, earthquake and theft/vandalism cause more damage than ageing! Tim A
Re: filmscanners: RE: cd storage
Tim Atherton writes ... Why don't I just pass on the notes and info I marked as being important for me after I did this workshop (which I think has already been posted once here...) :) ... and thank you for these notes!!! ... In fact one of the biggest areas with longevity apart from the above was error level on the recording side, which depended on a number of factors and got very complicated. Depending on your burning software, running the test disk option actually tests it AFTER burning, to let you know how much error there was (there is always some error). Also, over time, CD burners deteriorate mechanically, introducing more error. ... Regarding the write ... and if I assume most are using the Adaptec software, turning on the "verify after write" is a preference you may have to look for. Rather than parameters set when you choose "record", it is found under 'file|properties'. That is, if you choose a faster CD write capability of many drives ... do turn on verification. shAf:o)
RE: filmscanners: RE: cd storage
The info I had from the conservation scientists who are researching CD longevity and archival storage was; No sticky labels of any kind (they both unbalance and lead to read and write errors, even round ones + the glue is probably detrimental in the long term). Use only NON solvent based markers if you have to write on the CD's, and don't write on the disk itself if possible, but on the inner clear part where the serial number is. Remeber, the top part is the most easily damage, both by actual scratches, and by chemical deterioration. The underside is, comparatively, much more robust. Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of PC Sent: December 8, 2000 6:37 PM To: [EMAIL PROTECTED] Subject: Re: filmscanners: RE: cd storage My suspicion is that he has opinion and fact confused. Phil shAf wrote: I just thought I'd add to this thread something a Plextor support person had said to me, after I had called him on a different matter. As a BTW, he claimed that having labeled CDs (blank on both sides) with a felt pen, this could in the future cause problems with the data on the other side. His implication was to always label the inner part of the CD, OR buy blanks with a painted side, OR used stick-on labels which wouldn't imbalaced the disk. shAf :o)
Re: filmscanners: RE: cd storage
Michael, All this stuff about CD-R durability is speculation at the moment, sometimes well-informed, and sometimes ill-informed. I'd give your support person's views a lot of weight if I knew he'd properly researched the field, and had some data or reasoning to back his judgement (rather than hearsay), but otherwise I'd trust my own technical judgement. My particular personal opinion, based on my relevant scientific background, is that there are plenty of things to worry about over long-term storage on CD-R. However, chemical or photon penetration of the metallic reflective layer from the top (label) side is not high on this list, precisely because it's an excellent chemical and optical barrier layer, protecting the data from that side. It is, nevertheless, very vulnerable mechanically. Use a recommended non-corrosive pen or a paper label, and worry instead about still having a machine and operating system that'll read the disk in 20 years time, or about the dye data clouds and/or their enclosing polymer matrix self-destructing. I think it'd be sensible to recopy valuable irreplaceable image files (keeping on-topic, you understand) every few years. Regards, Alan T - Original Message - From: shAf [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, December 08, 2000 11:46 PM Subject: RE: filmscanners: RE: cd storage a Plextor support person had said to me...that having labeled CDs (blank on both sides) with a felt pen...cause problems with the data on the other side.
Re: filmscanners: RE: cd storage
Tim, You could always peel off the label and try again, if a disk doesn't read correctly. Surely an imbalance will show immediately. Everyone should test their CD-Rs after writing them, preferably in another drive. That 's a different issue from the longevity of the data. Have your conservation scientists any published work with real data, to which I could refer, or are they just guessing, based on their knowledge of the technologies involved, as I am? We all need this information to keep our lovely images pristine for our grandchildren, but I have the uncomfortable feeling that everyone's guessing, and no-one knows. We need some references to the scientific literature, don't we? Has anyone got a tame information scientist who'll find out the real state of the art for us? Alan T - Original Message - From: Tim Atherton [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, December 09, 2000 2:46 AM Subject: RE: filmscanners: RE: cd storage The info I had from the conservation scientists who are researching CD longevity and archival storage was; No sticky labels of any kind (they both unbalance and lead to read and write errors, even round ones
RE: filmscanners: RE: cd storage
How about magneto optical? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Alan Tyson Sent: Friday, December 08, 2000 11:10 PM To: [EMAIL PROTECTED] Subject: Re: filmscanners: RE: cd storage Tim, You could always peel off the label and try again, if a disk doesn't read correctly. Surely an imbalance will show immediately. Everyone should test their CD-Rs after writing them, preferably in another drive. That 's a different issue from the longevity of the data. Have your conservation scientists any published work with real data, to which I could refer, or are they just guessing, based on their knowledge of the technologies involved, as I am? We all need this information to keep our lovely images pristine for our grandchildren, but I have the uncomfortable feeling that everyone's guessing, and no-one knows. We need some references to the scientific literature, don't we? Has anyone got a tame information scientist who'll find out the real state of the art for us? Alan T - Original Message - From: Tim Atherton [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, December 09, 2000 2:46 AM Subject: RE: filmscanners: RE: cd storage The info I had from the conservation scientists who are researching CD longevity and archival storage was; No sticky labels of any kind (they both unbalance and lead to read and write errors, even round ones
RE: filmscanners: RE: cd storage
I just thought I'd add to this thread something a Plextor support person had said to me, after I had called him on a different matter. As a BTW, he claimed that having labeled CDs (blank on both sides) with a felt pen, this could in the future cause problems with the data on the other side. His implication was to always label the inner part of the CD, OR buy blanks with a painted side, OR used stick-on labels which wouldn't imbalaced the disk. shAf :o)
Re: filmscanners: RE: cd storage
In summer '99, for the total eclipse, I experimented with viewing the sun through CDs, and found two together gave comfortable viewing. *That* would have made a nice photo :-) Regards Tony Sleep http://www.halftone.co.uk - Online portfolio exhibit; + film scanner info comparisons
RE: filmscanners: RE: cd storage
I promised I would send some more info on the consumer test that I had read. Please read the previous mails in this thread to place the information in context to avoid repeating info and unneccessary mail. In fact, don't even read it ;-), it is just here so that I keep my word. 3 types of burners using 3 different brands: Philips CDRW 800 (8x) HP CD-writer Plus 9310i (10x) Plextor Plexwriter (12x) longevity indication test: put recorded CD under UV lamp with label side up for 100 hours Accompanying explanation said that light from the up-side of the CD will also reach the other end. Especially the outer boundary of the CD will be prone to have less longevity. Tests of recorded CDs were e.g. done on a 10 year old Yoko CD player. That player was unable to play a lot of the tested CDs correctly. On color:Not all green CDs were good (the worst 2 were green! and a few of the best were green) and not all blue CDs were bad (one TDK was reasonably good). The test speaks about 30 CDs, not some high number of CDs of 30 different 'brand and types'. Since there were 30 different brand and types tested I can't tell if they tested with only one per brand and type or with many. This makes the test much less useful. They suggested to look at http://www.digido.com. They noticed that three brands (Philips, Sony and Basf) and type of CDs that had a verdict 'GOOD' all came from the same factory, Taiyo Yuden Company. Here 10 of the best (best 2 because of price/performance on top): typecolor writing side == == Sony cd-r 74/650green Memorex 829306-25 green Hewlett Packard C 4437 Agreen TDK cardflexgreen Traxdata TXS 874green Philips gold prof. all speedgreen Philips silver premium green Basf/Emtec Ceram Guard green Kodak Ultimagreen Arita Gold green This was just what this particular test indicated. I think that the other mails in this thread can therefore give you a better indication of which CDs to buy, perhaps the last one of Tim Atherton below of which I snipped the tail part -Original Message- From: Tim Atherton [SMTP:[EMAIL PROTECTED]] Sent: Thursday, November 30, 2000 12:29 AM To: [EMAIL PROTECTED] Subject: filmscanners: RE: cd storage Here is some info I posted on another list, based on a recent workshop I went on. This was on the preservation of modern information carriers (optical and magnetic media) run by two conservation scientists from the Canadian Conservation Institute: But basically, while testing is still being done, the following generally hold true; [Oostrom, Jerry] [snip: look into archives to find this long mail]
