Yet almost every quilter who does not wash her fabric before cutting and sewing will have a story to tell about fabrics bleeding, dyes migrating to other fabrics, and uneven shrinkage.
Reasons to wash fabric before making a quilt:
1. Washing removes sizing and other chemicals left in the fabric during manufacturer. Some may have allergies to new fabric.
2. Washing shrinks the fabric so the quilt won't shrink unevenly in later washings. Each fabric will shrink at a different rate and this could cause lumps and unevenness in the quilt.
3. Washing insures colorfastness. If a fabric bleeds too much it can be treated with a salt or vinegar rinse or discarded before using it in a quilt. After a fabric is sewn in a quilt it can easily bleed onto other fabrics.
I personally have had many experiences with unpredictable fabric. Following are a few examples of some recent experiences with new high quality quilting fabric.
Bleeding -- We all know what a red sweatshirt does in the laundry when mistakenly put in a load of whites. Everything turns pink. The same thing can happen to your beautiful quilt with hours of work invested in it.
Recently, I have had two different red and black printed cuts of fabric bleed extensively. I simply placed the new fabric in a basin of warm water. Within two minutes the water was the color of black cherry gelatin. I continued to rinse this fabric in fresh water. I put it through at least ten water baths in the basin before the water ran "clear" so I could rinse and dry the fabric. The same process was repeated with the second piece of fabric. The actual color in the fabric is still very strong so it did not loose needed dye, it simply lost excess dye. If I had not pre-washed this fabric the white fabrics in my red, black, and white quilt would have turned pink.
Salt or vinegar in the rinse water to "set the color" is recommended by some and thought useless by others. Neither product will harm the fabric so use them if you wish.
There is a product available called Shout Color Catcher. It "absorbs and traps loose dyes to help keep colors vibrant". They are small sheets that can be tossed in the wash and rinse cycle to trap and absorb dyes. They are safe to go though the dryer. The sheets are only good for one use and should be discarded. A box of 24 Shout Color Catcher sheets is available in the laundry section of your grocery store for less than four dollars.
Fading -- I have had fabric fade so much that the new color no longer coordinated with the remainder of the quilt. The same fabric also showed signs of crocking and when the sizing was washed out, the fabric was very loosely woven and flimsy. I would not want that fabric in my quilt.
Crocking -- Crocking is when the color actually rubs off in the laundering so there are light streaks where the fabric was folded in the spin cycle.
Shrinking -- In the past we have been instructed to wash our fabric because it usually shrinks in length. And while this may be true, I have had first quality cotton fabric shrink as much as four inches in width! This is a good reason to purchase a little extra fabric. When fabric is only 38" wide after shrinking, extra fabric may be needed to cut the required number of pieces.
After similar experiences over many years of quilting I find that by washing my fabric before cutting I am avoiding many problems that would come later in laundering.
How I handle my new fabric
I wash all my fabric before it enters my quilting studio. When I purchase new fabric, I take it to the laundry room where I have a pinking rotary cutter, mat and ruler available. I trim all cut edges with the pinking blade. This keeps all those strings from forming along the cut edge of the fabric.
There is an even easier and quicker way to keep your fabrics from "stringing". Just cut a corner off on each side of the cut ends. Only takes a second and really works.
I always pre-test dark fabrics in a small basin of water for bleeding. Fabrics in the red family tend to bleed the most, followed by black and other very dark fabrics. Once I see a fabric is not bleeding, I place them in the washing machine on a gentle cycle and cool water. I always wash dark fabrics separate from light fabrics.
If I plan to press my new fabrics, I dry them in the dryer on low until slightly damp. Then press them as needed. If I don't dry more than 5-6 yards of fabric at one time they come out of the dryer with less wrinkles. I seldom press the larger pieces until I am ready to cut them.
If the fabric pieces are very small such as fat quarters or fat eighths, I either wash them by hand or place them in mesh bags to keep them from twisting and tangling. If they are in mesh bags, I wash them in the washer and dry in the dryer. I find smaller pieces sometimes need more pressing than larger pieces. I almost always press my fat quarters and fat eights.
Always make sure your fabric is completely dry before putting it in any type of storage container. I usually leave mine out on a table for several days to be sure. Then I add it to my stash.
If I purchase a kit of very small pieces of uncut fabric such as for a block of the month I wash them by hand in a basin and hang them to dry. Press as needed.
Pre-cut kits would be more difficult to pre-wash. I would hesitate to pre-wash a precut kit. Definitely do not wash pre-cut pieces in the washing machine. If you do not wash a pre-cut kit, remember to use a dry iron when pressing your seam allowances. If you use a steam iron, once moisture and heat comes in contact with these fabrics they will shrink unevenly. The lengthwise grain shrinks at a different rate than the crosswise grain. It is also recommended that if you don't pre-shrink fabrics for the top you should not pre-shrink the batting or backing.
Flannel fabric will shrink even more than regular quilting cottons so it should be pre-washed. If flannel fabric becomes too soft from washing and drying, a light spray of spray sizing or spray starch when ironing would renew the body or stiffness of new fabric.
Cotton batting will shrink quite a lot and will give your quilt the "antique" look. If this is the look you wish to have, do not pre-shrink your cotton or cotton blend batting. If you don't want this shrinkage to occur, you would need to pre-shrink your cotton and blend battings. You do not need to preshrink 100% polyester batting.
Most brands of batting will have pre-shrinking instructions on the package. If not, simply fill your washing machine with warm water. Unroll and place cotton batting in water. Turn washing machine off and let the batting soak for at least thirty minutes. Do not agitate. Spin water out on a very short spin cycle and dry the batting in the dryer on low temperature.
Pre-shrinking fabric is a necessary and important step to quality quilt making. If you wish your quilt to be flat and smooth you don't want your fabric to be shrinking at uneven rates.
If you do not pre-shrink any of your quilt fabrics or batting you will have some shrinkage after it is washed the first time. This is what causes the crinkly look of the antique type quilts that are so popular now.