Why Fluorescent Lamps are Sometimes Dimmer than Expected?

"I recently replaced a kitchen overhead fixture with two 75 watt bulbs with a fluorescent one having two 20 W bulbs. Guess what? Not enough light!" Somehow I was under the impression that a watt of fluorescent lighting produced many more candles than a watt of incandescent lighting, but obviously, I overestimated the ratio." A 20 watt fluorescent bulb of a higher light output color should make as much light as a 75 watt incandescent (1170 to 1210 lumens), BUT: • A few fluorescent lamp colors are dimmer, such as Deluxe versions of cool white and warm white, and a few others. • Fluorescent lamps only make full light output in a somewhat narrow temperature range. The fluorescents will probably not make full light when they first get started. They typically make more light after warming up for a few minutes, then may lose a bit of light output if they warm up past optimum temperature. • Some ballasts do not make fluorescent lamps produce full light. Some 20 watt fixtures use a multi- ...  more