Archived posting to the Leica Users Group, 2004/02/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In a message dated 2/1/04 7:52:45 AM, owner-leica-users@mejac.palo-alto.ca.us writes: << I say color accuracy, but just yesterday, I found a color that not only film, but digital can't render right. I photographed a pariba tourmaline. The color is a very intense blue/green that is highly prized. Actually, you see the two colors depending on which angle the facets are in relation to the light. (We call it pleochroism.) The stone was nicely cut, no inclusions, and it was almost 7 carats - at about $20,000 per carat. Gorgeous. But I could NOT get my Canon D60 to get it right. And one of the best gem photographers doesn't seem to be able to do it with film either if any past photos I've seen are evidence. Photoshop at 16 bits couldn't get it right either, holding the stone up to the computer screen. The color is simply outside the gamut of any photographic process I have access to. >> The trouble is that most chemical and electronic color processes use only three fixed colors to form an image. They are all based on the Young-Helmholtz theory of color vision that specifies that a minimum of three colors are necessary to specify colors. But there are some colors that the eye can visualize that lie outside the range embodied by the three primary colors incorporated in film layers or digital sensors. The human eye uses more than three types of color sensors - but then nature is not constrained by accountants or production engineers. Larry Z - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html