Archived posting to the Leica Users Group, 2003/09/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Mark, Calumet still sells the Zone VI Wratten #90 viewing filters, mounted in discs with cutouts for 35mm, 4x5 or 6x6 aspect ratios. The discs - about 2 or 3 inches in diameter - are meant to be hung from the neck. Sonny suggested that the color of the monochromatic viewing filter may not matter. I remember from Ansel's class that the reason why the Wratten #90 is used as a viewing filter is that it lets the eye see the tonalities of a scene in a way that approximates the response of panchromatic film. This helps, for example, to avoid merging tonalities. Since my recollection of optical physics is exceedingly dim (pun intended), I do not want to be judged too harshly for saying "the Wratten #90 filter removes chroma", the phrase that sticks in my mind. Oliver Bryk - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html