At 01:30 AM 6/30/01 +0100, Lee wrote: 70 DPI would be something like a 9 pin dot matrix printer. True, some manuals were that poor but certainly not a majority of them. Many old manuals were photo-typeset and then offset printed. You see "nobody" defines the empty set, and that is patently untrue as to risk making all other statements you offer to be rejected out of hand. Laser printers, known as "digital printers" in the publishing world, are used for short run publications (less than say 2,500 copies) and they are not uncommon. Hmmmm. If a manual was phototypeset on a CAT phototypesetter (most popular phototypesetter in the publishing industry in the mid 70's.) then the resolution is 2000dpi (they spec it in lines/millimeter but my recollection is that it was about 2000lines/inch after conversion) so those manuals should be scanned at 4800 dpi right? Basically, I think you may be mistaken on a few of your numbers. --Chuck

On Sat, 30 Jun 2001, Davison, Lee wrote: Why should that matter? Ink on paper is still ink on paper no matter how old. The resolution required to scan printed pages with any sort of decent quality remains the same whether you are scanning 5 century old pages or 5 second old pages. Sure they do. No it isn't. It's looking toward the future when we'll have a terrabyte hard drive in our desk tops (end of next year probably) and bountiful bandwidth. 600DPI would be cumbersome for most folks today but two years from now we'll all be bemoaning the fact that most scans done today were only 300DPI. Pishposh! What IS the source resolution? Of a printed page? HELLO! Close enough to infinity to practically call it that!!! Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org

--- "Davison, Lee" <Lee.Davison(a)merlincommunications.com> wrote: Printing on a dot-matrix device, perhaps. My reaction exactly. Last time I checked, the alphabet hadn't changed much. Besides, some of the legends in the drawings are in letters that are very tiny, and there's always the line art itself... scaning at 70dpi would be next to useless. Excepting my own mother ("Breeches of Silver", which she "typeset" for the Rev. Richard Starling on her 4Mb Mac SE about 15 years ago). She did the photo-readies which were sent to a "real" printer for offset production. But seriously, no... it's not ordinary to make books on a laser printer, partially because the ink technology isn't as stable as what is used in offset presses (reflowed resin, vs. oil-based printing inks). The resolution isn't the primary issue. Hardly. With cheap 80Gb disks and CD burners, storage space really isn't an issue compared with the value of the data. I personally have a couple of boxes of PDP-8 docs. I have been digging around on pdp8.net and so far, have only turned up a couple of docs that I have that aren't up there (and yes, I will be scanning mine at 300dpi if not 600dpi ;-) Information theory suggests that sampling any signal at more than twice its frequency does not result in aquiring any additional content. For pictures, I scan at well over the "standard" web resolution of 72dpi, but I do reduce the scans to approx 72dpi for display on the web (and at much lower for thumbnails). For printing, I have to agree that 300dpi is a good compromise between file size and quality. Trying to read the small print on a DEC maintenance print that has been scanned at 300dpi is nearly impossible. -ethan ===== Visit "The Seventh Continent" http://penguincentral.com/penguincentral.html __________________________________________________ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/