Colour temperature of CFL bulbs

<p>What has anyone's experience been with the <em>true</em> colour temperature of those new "squiggly" compact fluorescent lamps (CFLs)? Most CFLs are sold with a "warm white" designation and a marked temperature of 2700 Kelvin on the package. The older fluorescent tubes had differing wavelengths present in a single output.</p>

<p>I remember many moons ago we used various CC filters, depending on the colour temperature of the various fluorescent tubes, e.g. cool white, daylight, warm white. It was dicey with slide film to get it just right, especially with mixed sources.</p>

<p>I'm thinking that a four-layer colour negative emulsion like Fuji markets may be better with these bulbs in available light than using a transparency film. I'm just not sure how faithful to either daylight or the old incandescent lamps the CFLs are.</p>

<p>CFLs don't produce a steady color temperature. The mercury vapor creates spectral spikes that, when combined, produce about 2700K apparent color temp. Fourth-layer color films will do better than normal films, but they will by no means produce excellent results. </p>

<p>Here's a color corrected version (PS autocolors)</p><div></div>

<p>Fluorescent light sources are always a problem because, as Nicholas says, their spectrums are full of spikes. In some ways these difficult light sources are like problem colors (heavenly blue morning glories that may reproduce magenta, azo green fabric dyes that may reproduce brown, etc.) All of these problems get better when a film has more accurate color reproduction. Accuracy in this case is defined by what the human eye sees. There are several ways to get film to reproduce color more like the human eye. Fuji uses a fourth layer in many of their products and achieves good results. Kodak films use a combination of spectral sensitizing dyes and DIR couplers that also produce accurate colors. IMHO, the Portra 160 and 400 films are unbeatable for color accuracy. They will do well with fluorescent lights.</p>

<p>I will experiment with different stock. I have a freezer loaded with bricks of Portra 160 and 400, plus loads of loose rolls of Fuji. I had used Fuji Pro 800Z at the NY auto show back in April and was satisfied with its rendition of mixed lighting situations. I haven't had the chance to experiment with the Portra yet.</p>

<p>Thanks for all of your comments and advice.</p>