Well, it CAN'T be that I'm expanding...

I admit it, when it comes to clothes, I really just don't care. While I might like or dislike the color or pattern on a shirt, if it's the right size and it doesn't make my eyes bleed, I'll call it wearable as long as it fits and doesn't have any holes, and occasionally beyond that. One of the benefeits of this laissez-faire attitude toward my clothing is, I really don't spend much on clothes, since I only decide I need more shirts or pants when I find myself having to recycle the few I have left so often I start getting funny looks.

One of the downsides to keeping a shirt for a few years though, I've found, is that the darn things shrink. Suuuuuure, you say, it's all the shirt's fault. Then you'll wink, because you're being clever. Stop that. I know I'm right about my shirts shrinking, because they only shrink in one direction.

One day I've got a perfectly nice shirt and two or three wearings later, I'm showing more belly than Cristina Aguilera... umm... has. But that's not the point. I'm 6 foot 3 (1.90m), so there's a fair amount of shirt length there, and it just vanishes in big chunks sometimes. After going through my closet a few weeks ago and finding several shirts that had somehow become wider than they are tall, I decided to toss them out. But the mystery remained: why are they only shrinking lengthwise?

It all has to do with scales. Most fibers (silk is an exception) have microscopic scales on them. When a fabric is woven, a bunch of strands of the fiber are pulled lengthwise next to each other, these are called the "warp." Then, other strands of the fiber are woven through the warp fibers, these are called the "weft" (you can remember this because they go from right to weft. [rimshot] Thanks, I'll be here all week.)

Anyway, when the weft strands have been woven through the warp strands, you have a piece of fabric, and due to the scales, the strands tend not to move much after that, which is a good thing for people who like plaid. Everything's hunky dorey and this is how you buy the shirt... the warp going up and down your torso (and down your sleeves generally) and the weft going across your chest. I assume this is because the shirt or sleeves getting shorter isn't as much of an issue as the whole thing getting tighter.

After you wear your new piece of adornment, you toss it in the wash and drier. What happens when the shirt gets hot is that like almost all hot things, the fibers expand a little. As they cool off and start to contract, the scales aren't in such close contact any more, and there's room for some slippage, and this is where the shrinkage can make its move.

Okay, but why only in one way? Remember how it was woven in the first place? The warp fibers were stretched to make it easier to weave the weft fibers -- and those weft fibers weren't. They were just drawn through with relatively little strain. So the warp fibers sieze the opportunity and start to revert to their original length. The process is called "relaxation shrink" since the warp fibers are relaxing toward their original length.

According to clothing industry standards, the stanard for relaxation shrink is around 2-3% over the life of the garment, but they define "life" as 2 years or about 40 wearings. If you wear things like I do, more often than that, for longer, or both, the shrinkage will continue. Their answer? Buy more clothes!

Hello, planned obsolescence, my old friend. Washing things in cold and not machine drying will also help. Or wear all silk, I can think of worse fates. One more mystery solved, see you Monday.