Archived posting to the Leica Users Group, 2001/07/30
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Fluorescent lights are rated by color temperature, degrees kelvin, and by color rendering index (CRI). Of course we know that 5,600 degrees kelvin is close to natural daylight and 3,200 K is incandescent. A CRI of 100 would mean that the lamp has a continuous spectrum. Common fluorescent lamps have a CRI of 60 or 70. That means that there are lumps and things like nasty green spikes in their spectrum. The best lamps have a CRI of 90 and above. The lamp manufacturers catalogs are online and if you are bored can make interesting reading. I have an old enlarger that I use for occasional MF work. It uses a circular flurorescent lamp. I found that with a halfway decent lamp of 3,200 K and mid 80's CRI I can print pretty effectively with variable contrast filters. Mike D - ----- Original Message ----- From: "Shel Belinkoff" <belinkoff@earthlink.net> To: <leica-users@mejac.palo-alto.ca.us> Sent: Monday, July 30, 2001 9:01 PM Subject: Re: [Leica] Light in the darkroom? > Bernard Cousineau wrote: > > > Verilux bulbs (http://www.verilux.net). > > [...] overpriced, longer lasting, and > > optically a few notches above. > > Could you explain how one light bulb can be optical superior to > another? What characteristic should we be looking for? Sounds like > nonsense to me. > -- > Shel Belinkoff > mailto:belinkoff@earthlink.net > "Why should I use a meter? What if the darn thing broke on me > when I was out making a photograph? Then what would I do?" >