On 7 Jan 2002 at 11:53, Shel Belinkoff wrote: > Today I went to my local high-end pro lab to pick up some film, and > asked about scanning B&W negs. According to the fellow I spoke with, > who may not ne the most knowledgeable guy in the shop - but by no means > a dunce - they can do a drum scan of a 35mm B&W negative that will > generate a file of about 640mb. Is that possible? He also said that > they can generate a 36" x 54" print in house from that size scan, and > larger by going outside. > > It would seem that in order to get good quality going that large, one > better be scanning a perfect negative <g>
Hi Shel, The file size sounds correct, drum scanners don't use a linear array that sweeps down the image like a flat bed or consumer film scanner, in stead they use a single very focused dot which moves along a rotating drum. So in effect the resolution is controlled by the focus point size and the increments by which it moves down the drum. The unfortunate thing that I have found with drum scans is that the scanner software (and operator) tend to apply post processing of the image that renders it suitable for printing to press but bad for photographic purposes. Images generally tend to suffer from excessive application of unsharp masking making the contrasty edges in the image look quite false. The other thing is that at the sort of resolution that you mention you will get a lovely rendition of every grain in the image if the film is faster than ~ISO100. To put it into perspective there is little information to be gained by scanning TMZ at anything beyond 2000dpi, beyond that you just get a better idea of the shape of the grains. There are arguments that the final image will look more analogue the higher the resolution however I've yet to see a real difference. The biggest advantage in B&W scanning is the bit depth ie the fact that you can record more shades of grey in any one pixel. The last comment rings true, once you have a good scanner you wont believe how critical you can become :-) Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
