A measure of how ugly fluorescents are is CRI. A technical measure of the quality of light is the Co​ lor-rendering index (CRI). A black body (for our purposes, a heated object, like the sun or an incandescent light) emits a particular spectrum of color, depending on its temperature (hotter bodies given bluer light; cooler bodies like candles given redder light). Fluorescents emit a line spectrum (only a few wavelengths), instead of the continuous spectrum (blend) of all visible wavelengths that the sun and incandescents emit, which is why they are ugly and which is roughly measured by CRI.

loki:

Which is why they use incandescent bulbs when they review graphic proofs? Nope, its 5000k fluorescents or natural light. Fluorescents cover the blue range that incandescents seem to miss and hit the red range that natural lighting diminishes. The idea is to reproduce the colors as close to the established color range for the graphics as possible. Blues come out crisper in definable shades under fluorescents.

People seem to love that yellow flickering fire place glow which an incandescent delivers in an unflickering manner. Fluorescents at 5000k typify noon day sun. Following a safe protocol with disposal is necessary and the unroar is overblown when one takes into account how most people handle chemical cleaners, bleach, fertilizers, and pesticides. One danger worth noting has to do with the blueness of the light from fluorescent lighting, children should not be allowed to look into it as it can damage the eyes over time.

Loki is correct: fluorescent lamps do not produce the spectrum of visible light in the even distribution of the sun, or a glowing filament. This is why the CRI is significantly below 100. A CRI of 100 shows colors like natural light: incandescents are basically CRI 100. The mercury vapor of a CFL produces ultra-violet light, and the fluorescent power converts it to visible light. Usually a mix of three powders is used, each powder producing a different color of visible light, but this mix only approximates natural light. More powders can be used in the mix, but then the energy efficiency drops and the cost goes up. However, CFLs can at least easily change the color temperature, making a bluer (colder) or redder (warmer) average. But the CRI is stuck at around 80.

"white" LEDs also rely on fluorescent powders, so they have a similar problem.

tim:

which is why we use incandescents to proof graphics? You can not get an incandescent bulb that will approximate natural lighting and reveal all of the colors in graphics the same as natural light. So we have a choice, either we go outside in natural lighting or we use 5000k fluorescents. No one grabs an incandescent for this purpose.

You proof graphics under fluorescents to see what they look like under fluorescents. If you expect people to view your graphics under fluorescent, you proof under those -- same reason that some audio engineers master with reference speakers that approximate what their listeners will use.

Unless specially manufactured, objects and dyes look different under different light: if you care about how something will look in daylight, use a light with high CRI and the appropriate color temperature. If you want to see what something looks like under fluorescent (say, what a graphic will look like when a reader reads in under their fluorescent reading light), you have to use fluorescent.
With the exception of carefully formulated dyes (specifically designed to have the same response under fluorescent and a given temperature of daylight), you cannot tell what something will look like in a different light, and need to proof under the appropriate light.

loki:

Incandescent has a yellow or reddish cast to it which softens colors. A quick test is to take a series of different hues of blues and try to pick out the different ones. It is damn near impossible to do so. We proof graphics under 5000k fluorescent as it brings out the colors sharply, more so than incandescent, and approximates the noon day sun which is the better of the two.

As far as inks, do you know the difference between flexographic, lithographic, and rotogravure printing? In the processes of the last two there is an overlay of dot patterns (of varying patterns), at varying printing stations, to achieve the final color and look. While you can darken or lighten a color; it is the dot pattern and the size of the dot which will determine the crispness of the image and the sharpness of the color. Misalign the dots and the color may be muted and the image blurred. Much of what is seen in stores today is rotogravure printing.

I will give you this . . . most stores are lit using fluorescent lighting.