Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 (Tek) 9/28/84 based on 9/17/84; site tekecs.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!mtuxo!mtunh!mtung!mtunf!ariel!vax135!cornell!uw-beaver!tektronix!orca!tekecs!hyder From: hyder@tekecs.UUCP (Paul Hyder) Newsgroups: net.rec.photo Subject: Re: film sharpness (Kodachrome) Message-ID: <5476@tekecs.UUCP> Date: Wed, 26-Jun-85 23:48:08 EDT Article-I.D.: tekecs.5476 Posted: Wed Jun 26 23:48:08 1985 Date-Received: Fri, 28-Jun-85 01:31:30 EDT References: <2807@decwrl.UUCP> <614@sfmag.UUCP> Reply-To: hyder@tekecs.UUCP (Paul Hyder) Organization: Tektronix, Wilsonville OR Lines: 29 For the record the Kodachrome will always be sharper. The primary difference between Kodachrome and Ektachrome is the method of dye production. The dye is present in Ektachrome in colorless form and is converted to colored form in processing. The dye molecules are large and sharpness suffers. Speed increases also can degrade the sharpness by requiring larger silver crystals but the new technology is reducing this factor reapidly. The other problem is that the extra dye is not removed in processing of Ektachrome, it just stays there in colorless form. As Ektachrome ages these residual couplers can become colored and cause color shifts in the images, N.B. this is in addition to any "fade". Kodachrome is a multi layer black and white emulsion with coupling sites but no dye molecules. The quality control is easier and the sharpness improves. Processing involves linking dyes in the chemistry to the correct sites (Yep, three color developers). This results in a sharper image without residual colorless dyes waiting to change. You do have to put up with the speed being slow and the fact that you can't process it yourself. (Well, you can't process it yourself easily. The chemical control lab costs would drive most people under, the chemistry doesn't come in easy to use boxes.) I use Kodachrome unless speed is a factor. Paul Hyder { ...tektronix!tekecs!hyder } [Guess 5 years as a Tech Rep in the Photo Industry wasn't a waste after all.]