Measuring fabric before and after washing it
 

I am definitely in the "if it's washable, wash it before cutting it" group. I want to wash the thread, too, but that has not seemed feasible!

Anyway, I have measured hundreds of pieces of fabric before and after washing. I was wondering if there actually was shrinkage - because a couple of pieces of cat print fabric were about 37 inches at the time I bought them - and were only 35 inches long when I wanted to sell them!

What I have found:

Most of the cotton woven fabrics shrink
Usually the shrinkage is in only one direction - I am unable to predict ahead of time which direction it will be
Brand name does not seem to matter - I have had shrinkage (and bleeding) from every line - including ones that I had "assumed" would be "better"
I have had shrinkage up to 2.5 inches in width on a 42 inch Michael Miller black (from three or four different bolts)
Even a Roc-Lon "pre-shrunk" muslin shrunk about two inches in length per yard when I washed it! That did surprise me.

It matters enough to me to bother with the soaking in hot water, then washing gently and drying "until done" before cutting the fabric.

these are the reasons I wash also. I used to wash general sewing fabrics, too, but don't do much general sewing anymore

I pre-washed 5.25 yards of backing for my current project. The edges were serged first and then trimmed so that was about an inch. Trimming off the serged ends lost another inch. Measured again and it was 4 inches shorter so there was some shrinkage.

A friend says her king sized quilt shrunk about 8 inches after washing. She doesn't pre-wash fabrics.

I would rather account for shrinkage before cutting the fabric and quilting so I will pre-wash. Plus I don't want to pay for quilting that is going to shrink away.

I prefer to preshrink for the above reasons, but mostly because I hate the feel/smell of all the sizing and chemicals that end up on the fabric during the processing. I also don't use starch for the same reason, I don't like the way it makes the fabric feel. I've been doing some swaps, and once in a while I'll get fabric that was starched. It sure reminds me of why I don't like starching my fabric.

I'm also in the pre-wash camp. Working with reds, I found that an inexpensive Walmart piece did not bleed at all, while a Moda Christmas fabric bled repeatedly through several washes.
Methinks you don't necessarily get what you pay for. I've read comments about Kona solids not all being the same quality depending on where they are sold.
Anyway, it all comes out in the wash, so I wash.

I always pre-wash. Flannels shrink a lot .... I mean, a lot.

I do not always pre-wash everything but I will pre-wash for swaps and some specific fabrics that seem to have a looser weave or heavy sizing. The heavier the sizing the more I feel it needs pre-washed. The only time I do not pre-wash for a swap is when it is stated "do not pre-wash".

I'm a prewasher but not a pre/post measurer. Sometimes I wish I was!

Between shrinkage and manufacturing issues, I only plan on 40" of usable fabric in a strip any more. I've noticed that they are starting to put on better/truer measurements on bolts than 44/45" that was the standard measurement. Around Y2K I did a lot of fabric swapping, we used pre-washed fabric and made 10" squares and sometimes we all had issues being able to get our squares cut.

I tried to get people riled up some 20 years ago about the discrepancy between the 44/45" inch listed and the actual sizes even pre-washed. The mills/manufacturers know they are skimping on the measurement, they get all sorts of extra yards of length when you short it 2" along the width. You have to register the printing process, you know the size of your print area. I wrote letters to US and State departments of weights and measures, posted on line. Just couldn't get any traction. Quilt fabric is a billions with a B industry, and they are cheating you just as surely as shorting you a cup per gallon of gasoline and charging you for a full gallon.

I do most of my initial sewing as strip piecing and it makes a big difference on whether or not I can get my count. In my current project I needed 42" and I have that exactly! Maybe 2 threads difference other than the very unusable selvedges. That's a little too close for comfort and I had extra fabric so I cut extra strips but that meant with 30 blocks I could only fit in 3 comfortably instead of 4, so had to cut 10 strips instead of 8.

Should have measured first or at least cut one test strip instead of all 6. Would have done better fabric-wise to cut a 10.5" strip of fabric and then cut the 2.5" widths from that, less waste.

I will have to make a point to read what the labels on the ends of the bolt say.

Even 20 years ago, some of the bolt ends said Width: 42-43 inches.

I prewash my fabrics most of the time. This way if there is any bleeding or fading then it will be usually taken care of at that washing.

I used to wash everything...but hey! I got piecing to do....now I am selective when I prewash....quilt shop fabric I generally do not wash....unless it is red or black...and then I sometimes do a bit of testing by rubbing a white tissue over it and seeing if there is a color transfer...or sometimes, if it is going to be a lot of red or black, I toss it in the washer with a couple of color catchers...one red batik I have, has deeply colored color catchers during three washes...don't know what I am going to do with this one...I also will prewash flannel used for a backing...unless I want a puckered quilt which sometimes I do for flannel quilts....and IF I am using a cheaper quality backing flannel as it will shrink and I want to minimize that if I have pieced the top with good quality flannel...just did that for some scrap quilts I made. I also will prewash if I am using a lot of fabric from a lot of different lines and manufacturers...yep, some shrink more than others. I used to measure my tops before quilting, after quilting, and then again after washing....yep...I could lose a couple of inches after quilting and a couple more after washing....

I'm not a pre-washer, but this has gotten me to think that maybe I should be.

I was taught to prewash and so I did. Along came precuts and that didn't make sense to me to prewash them so I didn't. Then I decided, I'm not going to prewash at all! I have made at least 50 quilts probably more, numerous table runners, lap quilts, placemats etc. I have not had any issues at all. Once I am finished, I wash the quilt in warm water, perm press cycle and throw it in the dryer. I love the crinkly look the dryer gives it. Reading prior posts, it makes sense there had to have been some shrinkage but it didn't affect the quilt much. Since I did not measure before or after, I honestly can't say how much shrinkage there was. I really love the look and feel of the quilt straight from the dryer, and so I'm sure I 'll continue on with not prewashing. Except for garments - that fabric will get prewashed!

When I first started washing fabric, I did not bother to measure it before and after - until I started to sell some of the fabrics -

Even though I knew I had purchased a yard of whatever - and I usually brought home 37-38 inches of length - I thought I should verify the length before I posted it for sale. I was not very happy to find that most of my "yards" were now less than 36 inches in length.

I usually buy a bit more than the pattern lists - if it says 1/2 yard, I usually get 5/8 yard to allow for shrinkage and if it is cut crooked/off-grain.

I prewash all my cotton quilting fabric and the cotton I buy also make my husbands shirts. I hate the smell of the chemicals and the feel of the fabric. I even soak to preshrink 5" and all precuts before I use them. Don't want any surprises in my hand applique.

I prewash every piece of fabric that comes into my house.

At considerable expense, we had square dance outfits made by a professional seamstress but the group that was in charge did not prewash the cotton fabric before taking it to her. Brought them home, washed the outfits and they shrunk. I had to let them out as much as was possible from the seam allowances. Lots of unhappy square dancers. From then on, I made our outfits myself.

I'm a pre-washer also.

Surprised- I had a Wal-Mart red bleed so bad I had to wash 3 times.

I have also had Moda reds bleed.

My one bad story about bleeding fabric was a name brand fabric but I don't remember the brand bought at a quilt shop. I also used a blue from the same collection and had no problems. The red dye was just not set, and even though I had prewashed when I washed the quilt it came out not as I expected with blue, grey, maroon and twinkles of white it came out with bits of baby pink! I found another piece of the red from the same line (it is the same design I used in the blue) at a thrift shop and picked it up to use as comparison. The two fabrics below started out the same color (maroon). The one that is now orange-ish has been washed about 6 times and still bleeds...

So now in addition to prewashing I do a transfer test if I have any doubt. Before fabric goes into my stash and ready for scrap quilting I am sure of it.

Karen Brown of Just Get it Done Quits on YouTube has a great video on prewashing or now. https://www.youtube.com/watch?v=7f0HCDygUeI

She makes three small quilts for comparison. Imagine the difference it would make on larger quilts?

I wash fabric, for health reasons. I react to the chemicals in the fabrics. I get eczema which is very painful, so I wash the fabric.

But I found the information in Karen's video to be useful for other reasons.