----- Original Message ----- From: "Bob Blakely" <[EMAIL PROTECTED]>
> > Entering "film acceptance range" into the Google search engine generates one > (1) hit only. Film latitude generates about 673 hits. "Stop latitude" > generates about an additional 236 hits. "exposure latitude" generates about > 92,000 hits. > > "Dynamic" expressly implies continual change with time. Music has dynamic > range. Photographs do not. The scene may have it, but aside from multiple > exposures etc., still photographs do not record it. > > Regards, > Bob... > Control Systems Engineer & > Technical photographer... ________________________________________________________ FYI "Film acceptance range" is the number of stops of exposure that can be placed on the "straight line" of a film's characteristic curve, or between a prescribed point on the toe and another prescribed point on the shoulder of the characteristic curve, depending on the method being employed. Many people ~incorrectly~ call this the latitude. "Exposure latitude" is the number of stops that a scene's exposure can be varied up and down and still fit within the "film acceptance range". For instance if the scene you wished to record on a film had a brightness range of five stops, and the film you were using had a "film acceptance range" of eight stops, you would have an "exposure latitude" of three stops. However if the scene had a range of ten stops you'd be SOOL (presuming you couldn't adjust the curve by modifying development), and would be compelled to either put some highlight onto the shoulder, or some shadow onto the toe of the curve, or both, Incidentally, this is where film retains the edge over digital, because exposure outside the optimum range (on the straight line) of film doesn't immediately become unusable, but instead gradually diminishes in its usability according to the users taste. As for Google, that search engine is not an arbiter of right and wrong but simply a popularity contest. Firstly the results reflect the volume of visits to a site, secondly there are many more amateurs spouting shoddy factoids in vanity websites than there are professionals sharing textbook knowledge in either academic or corporate websites. FWIW the single result of the search for "film acceptance range" is <http://www.spectracine.com/ascartcle.html> and is the essay "Exposure Meters" by Jim Branch & Nasir J. Zaidi, ASC Member (Associate), web-published by the well regarded cine-exposure meter company Spectra. After reading it I would thoroughly recommend it to anybody wanting to learn some basic metering concepts from professionals in cinematography. OTOH the second site listed in the "film latitude" search results (the first required registration so I skipped it), <http://www.tpub.com/content/photography/14130/css/14130_209.htm>, incorrectly named "exposure latitude" as "film latitude". I also found such gems of claptrap and/or inept writing such as, "The gelatin ........ prevents action by a developer until the silver halides have been made developable either by exposure to light or chemical action. The gelatin also acts as a sensitizer for the silver salts", and "color films can be recognized because they contain the suffix 'color'." I could go on and on but I won't, that site is poo. The third Google result for "film latitude" was <http://www.jamesarnett.com/1-1-10-4.html> and doesn't actually contain that phrase, it is the page title in the html and ~never~ appears on the visible page. I won't waste any more time in this futile search. I studied photography at Sydney Technical College's School of Graphic Arts over twenty years ago, and I know what I learned, and it wasn't to be BSed by amateurs. And from a motor mechanic to whom I theorized about the cause of my car's engine disorder , I learnt the rhetorical question, "So where did you serve your apprenticeship, sport?" regards, Anthony Farr
