To Wash or Not to Wash: That is the Question
I am a proponent of not washing my fabric prior to working with it in most cases. It was how I was initially taught, and I haven't yet been adequately convinced to pre-wash my fabric in most instances. That being said, there are proponents of both. The decision is yours.
Pre-washing
Pros: Proponents of pre-washing fabric say the main reason they do it is to get rid of all the chemicals in the fabric that make it stiff. Additionally, washing pre-shrinks the fabric so that any subsequent washings won't change substantially in size. Fabrics, especially lower quality fabrics, can bleed colors. Pre-washing allows for the bleeding to take place independent from the final project. Even proponents of pre-washing say, though, that pre-cut pieces should not be washed, so you are combining washed with unwashed, which to me is problematic.
Cons: Pre-washing your fabrics makes a mess. Pulling apart the bits and pieces of shredded fabrics, untangling them, cutting off all the shredding, and ironing the fabric before starting my project is not my idea of fun. With the amount of shrinkage and raveling, the half yard that you purchased is no longer a half yard. If you pre-wash, get more than the required fabric to allow for this which means more money. Pre-washing washes out all the sizing in the fabric that actually helps make your cutting more accurate. The fibers in the fabric become loose and are more difficult to cut without reintroducing a sizing, which for me is a waste of money. Why take out the sizing only to put it back in? Finally, if you pre-wash, then you must pre-wash everything. If you dig from your stash, make sure that all those pieces have been pre-washed. Combining washed with unwashed fabric could have disastrous results because in the first washing, some fabrics are shrinking while others are not. This could drastically distort your project.
Have you ever gone to a class or retreat and bought new fabric for a project you are working on? Well, if all the other fabric you are using has been pre-washed, you shouldn't be using unwashed fabric with it unless you plan to pack a portable washing machine. They do make them, and I do have one. But I'm not going to pack it with the mountains of supplies I am already schlepping in.
Not Washing
Pros: Not washing your fabric means you can just dive in and get going. It is a sure way of knowing that all your fabric is equal. Color bleeding? if you purchase good, quality fabric from a LQS, bleeding is less an issue. Fabric manufacturers have perfected their processes over the years and the fabric maintains its colors. If you are concerned, color catchers are a good solution if you wash the final project. By not pre-washing, the half yard you purchased is actually a half yard. And those chemicals? Well, they actually help with cutting the fabric. I still add more starch, but it is less than what I would have to add if I had washed it all out first.
Cons: By not pre-washing your fabrics, your quilt will pucker and shrink a bit when you wash the quilt. This gives the quilt a puffy appearance that some like and others don't.
Suzy Quilts helps us see the difference with these two pictures taken from her website.
The quilt on the left used pre-washed fabric. The quilt on the right did not.
Keep It Simple
When considering whether to pre-wash, think about the end result. You needn't be a purist. Your final project will dictate what you need to do. If your project is going to be loved and used and washed frequently, you may want to pre-wash your fabric. If your final project is not likely to be washed, you don't need to pre-wash it. Garment sewing requires pre-washed fabrics. Any project that requires the final product be a specific size requires pre-washing if it is going to be washed. That is the pure and simple answer.