Jim Elwell wrote ""nit", which is one candela per square meter (cd/m^2)".
Yes, we need to define such units to make words shorter for the people to use. Definitely a term for square meter should be defined first. If people were forced to use '1000 cubic centimeters' instead of '1 liter', then metric system should have flopped long time back. As for 'inch' vs 'centimeter', people are free to use 'cm' instead which is much shorter and also universal. Madan --- Jim Elwell <[EMAIL PROTECTED]> wrote: > Date: Fri, 15 Mar 2002 12:21:13 -0700 > To: "U.S. Metric Association" <[EMAIL PROTECTED]> > From: Jim Elwell <[EMAIL PROTECTED]> > Subject: [USMA:18773] Short unit names > Reply-to: [EMAIL PROTECTED] > > Engineers who work with human-readable displays are > familiar with the unit > "nit", which is one candela per square meter > (cd/m^2). It is used to > specify how bright a display is (either directly for > some types, or via > backlighting for others). For example, a 150-nit > display will be readable > in roomlight, but washed out in sunlight, whereas a > 600-nit display will be > readable in sunlight, but too bright for viewing in > a darkened room. > > The unit "nit" is used for two reasons: displays are > a distributed light > source rather than a point source (so lux is not > appropriate), and, used > properly, it is a photonic unit, which means it > takes into account the > response of the human eye. > > There clearly is no directly equivalent SI unit > here, due to the photonic > nature. But I think engineers use it for another > reason: it is a short, one > syllable word. It is a heck of a lot easier than > saying "photonic-weighted > candela per square meter." > > I bring this all up to make two points: (a) SI does > *not* cover all > necessary uses of measurement systems, so there are > going to be new units > "invented," although we hope they are based on SI > (as nit is) and (b) > people inherently like short words, which I think is > one thing that turns > people off about the metric system (e.g., inch vs. > centimeter). > > I doubt anything can be done about (b), but I bet > that words like "klick" > (for kilometer) are not going to be eradicated even > in all-metric countries. > > Jim Elwell > __________________________________________________ Do You Yahoo!? Yahoo! Sports - live college hoops coverage http://sports.yahoo.com/
