Notice the images to the left, the "NOT Ott" produces a warm yellowish tone whereas the OTT produces a cleaner white tone. It is more like natural sunlight. The two light bases are each the same white color, but the one on the left picks up the warm tones from the "Not Ott" and looks yellow.

It is achieved because the OTT has a color temperature of 5000 °K. Fluorescent lights with color temperatures as high as (or higher) than 5000°K will produce photos with minimal color correction needed.

Compact fluorescents (screw-in base) are now available with color temperatures between 5000°K and 6500°K. Any of these work well for digital photography. They are sometimes marketed as "DAYLIGHT", but NOT "warm white", "soft white". or "cool white".

These non daylight bulbs tend to have color temperatures between 2900K -- 4100K.