The basis for any and every piece of clothing lies in the fabric- the maker or breaker and ultimately the identity of the article. And, therefore, is important! Before this project, I was a very unruly and defiant seamstress. I never ever prewashed fabric. Turns out, it's actually important!
For those like me, who don't really know what to do to prepare the denim, I am happy to report a great finding! Back in the back of my mind, I just knew I'd seen an article about this very thing, and so I searched through all of my magazines 'till I finally found it!
-------The following information was learned from an article in the Q&A section of the March 2011 issue of Threads magazine, contributed by Jennifer Hasemann):
Denim is a very important fabric to prewash, as many changes occur in the fabric that need to be handled before construction begins. Dyes and chemicals are added to the fabric during manufacturing that become affected by the initial washings, which can result in a lighter and softer denim. (The extent of these changes depend on the individual denim. Mine didn't lighten very much after washing. Jennifer noted that some detergents can be harsher to the color that other detergents.) The denim will also shrink after washing. (Knowing this, I got a little bit more yardage than I thought I'd need, hoping to counteract the shrinkage).
The way to wash the denim depends on the composition of the fabric. 100% cotton denim (what I used) can be washed and then dried in the dryer. If the denim contains over 8% Lycra/Spandex, DO NOT use the dryer. The heat will kill the elasticity of the denim. (If the percentage is only 1-3 percent, a cool dryer setting is still recommended). To achieve the goal of prewashing denim, it should be washed about 3 times.
Something weird that can happen when washing denim for the first times are random markings caused by the dye fading abnormally in the creases of denim that wrinkled in the wash. This occurrence is random and uncontrollable when it happens, but using fabric softener is a possible preventative measure. (I used fabric softener, and I saw none of these markings. However, my fabric didn't fade very much in the first place).