Standard Viewing for what purpose?
If you are setting up a vewing environment for the purpose of print eval, the viewing should be able to mimic where the prints will end up. If in a gallery, the odds are it'll be about 2850K as most track lighting in galleries are NOT 3200K.
If you are trying to setup an environment for viewing proofs intended for halftone repro, that's a different animal. There is a very specific ISO standard covering that. See: ISO 3664:2000 - Viewing conditions -- Graphic technology and photography. Since it's a copyrighted work, you'll need to buy the PDF to get the specifics. It's availabel on the ISO web site ISO 3664:2000 PDF
. It covers things such as color temp, luminance requirements and backgrounds...it can get technical.
Generally though, you aim for a neutral field in the background and a luminosity that can match the luminosity of the white of a computer display. Ideally at 90 degrees to each other so you must swivel your head to see one than the other. The ideal situation would be a dual spectral output, one for D50 and one to match or simulate that of the final viewing conditions of the hung print.
If you want to get REAL SERIOUS, you can also research another new ISO Standard, ISO 12646:2004 Graphic technology -- Displays for colour proofing -- Characteristics and viewing conditions. Also available on the ISO site.