Whiter whites, brighter brights, cleaner dirt!

I do not have a fleet of washing machines in which to conduct my tests. I don't have a radiation spectrometer for measuring the whiteness of whites the way Consumer Reports does. But I do have tools formidable in their own right at my service in my search for the best laundry detergent.

I have a laundromat right across the street from my apartment. I have skin sensitive to the faintest of soapy residues and an equally sensitive nose. But my biggest asset is New York City at my doorstep. The dirt, grime, spit, and fouler substances that regularly adhere to one's clothing here make this fine metropolis a veritable fantasia of filth.

But first let me rule out a few of the myths and scams of the laundry world.

Laundry Balls/Rings: Strange, hard balls or rings--$30 to $90 apiece--that purport to wash clothes without detergent by means of generating ions, or an undefined substance called "structured water." An apparently bogus product: Both Good Housekeeping and Dateline NBC have suggested that they wash clothes no better than plain water, and one manufacturer was sued for false advertising.

Ultra Concentrates: Remember how 10 years ago laundry detergent came in huge boxes? Don't they seem small these days? This was no technological advance. Under pressure from environmentalists, detergent manufacturers simply removed the fillers with which they'd been bulking up detergents to give an illusion of value. (The same thing happened with liquids--they just eliminated the water.)

Powder vs. Liquid: In 1995, a Consumer Reports study showed that powders outperformed liquids on all fronts. (The one exception: Tide With Bleach Alternative.) Conventional wisdom (as doled out on laundry Web sites and detergent hotlines) has it that powders are better in hard water and for ground-in dirt, while liquids are good for grease, but this was not backed up by CR's study.

Here's the dirt on detergent. There are two key ingredients: surfactants and builders. Surfactants reduce the surface tension of the water and increase its ability to rinse and wash. Whimsical chemists say they make water wetter. Builders create the proper pH balance and deactivate elements in the water that would reduce the effectiveness of surfactants. Detergents differ in the way they balance these two elements, and in their varying use of added ingredients such as bleach, enzymes, fluorescent whiteners, perfumes, foam control products, or fabric softeners.

This all presents an analytical conundrum. If each brand merely offers the same basic ingredients in different proportions, plus or minus a few bells and whistles, how was I to determine which was the best? I decided I'd take each detergent on its own terms. The most common label claims boasted of keeping colors bright, removing stains, eliminating odors, and being free of skin-irritating perfumes and dyes.

To the laundromat!

C olor Fastness Test: Since the arrival of detergents with bleach and bleach alternatives, color fading has been a concern of many launderers; various brands have accordingly begun to claim "color hold" bleaching or even that they "brighten brights while whitening whites." Normal chlorine bleach removes color indiscriminately: It attacks stains and dyes alike and converts them into particles that your detergent can easily wash away. It can also damage fabrics (especially protein-based materials such as silk and wool). In general, "color-safe" bleach just means oxygen bleach, which is much milder than chlorine bleach. It works by releasing hydrogen peroxide to break up or remove the color from organic materials but is gentle enough that it won't affect most fabric dyes. That stuff about brightening brights generally just means the detergent has some dye-transfer inhibitors, which help to stop bleeding dyes from staining other clothes. There's nothing in detergent that can make your clothes brighter, other that its inherent ability to get dirt out of them.