When I do my "Accurate Rotary Cutting" lectures, I'm often asked this question. This is definitely a personal preference. It also depends on if you usually buy more fabric than you need for a project.
Some reasons to pre-wash:
- Check for colorfastness of fabrics
- Allow it to shrink before putting it into a quilt
- Get rid of chemicals from the dying process
- Fusible applique works better when the sizing has been washed out of the fabric
Some reasons not to pre-wash:
- Like working with the crisp fabric
- Don't want to press wrinkles out of fabric that has gone through the dryer (if you take it out when it is slightly damp it is easier to get those wrinkles out)
- The quilt will never be washed so bleeding dyes aren't an issue
- The fabric isn't for a quilt, it's for an embroidery piece that I'm going to frame.
My personal philosophy is that you either always wash or you never pre-wash. Here is why. If I have washed everything in my stash, I know that everything has been shrunk and excess dyes have been removed. I used to work in a shop with someone who said if she was making a quilt that is meant to be washed, like a bed quilt, she pre-washed the fabrics for that project. If it was going into a wall hanging, there was no need to pre-wash them since you don't normally wash that type of quilt.
The problem I see with that is that leftover fabric from one project ends up in my stash. It is hard to remember what has been washed and what hasn't. So when that perfect fabric that was intended for a wall hanging will work in my scrappy bed quilt sometime in the future, now I am mixing fabrics that have been washed and shrunk with others that haven't. What will happen when the unwashed fabric shrinks after it goes in my quilt? What if that same quilt has a light background and one of the fabrics bleeds?
If you are working with hand dyed fabrics, they have already been washed in the dying process. So you should always wash any other fabrics that are going into that project.
Sometimes when I'm doing an embroidery project, I don't pre-wash that fabric. However, any extra fabric I may have, goes into the washer and dryer. So if I use it for something else later, it has been washed and dried.
If you don't like to pre-wash your fabric and are a little concerned that one of the fabrics might bleed if and when it is washed, there is something you can do to try to prevent that problem. Add one or two dye magnets to the washer when you wash the quilt. An example is Shout Color Catchers. These will absorb excess dye. The are found in the laundry aisle.
I use these when I'm pre-washing suspicious fabrics. They are also great when you buy a new outfit and don't want to wash that item separately. If you do stitching or quilting with rayon thread, you might want to use them if you wash that project. Rayon is not a colorfast material so it can bleed when washed. I have heard of many cases where red thread bled onto a white background which then became pink in places.
Whatever your decision, consistency is the key to a great finished project.