Batik fabrics pieced with regular quilting cotton fabrics ?
 

I will be making a quilt with batik fat quarters and regular quilting cotton fat quarters. I have never mixed the 2 types of fabrics in a quilt block. My question is will the fabrics shrink about the same? I was not going to wash the fabrics before making the blocks. Thank you!

Batiks ( at times) are a tighter weave then some other quilting fabrics, so tend to seldom shrink. If they are deeply saturated colors they may however bleed. I mix fabrics all the time- including washed and not washed fabrics. I do however check/ test hand dyes and batiks to make sure they won't bleed- if they do I wash them until they do not.

I also mix them. So far had not had any of my batiks run.

I have not had any issues, but I wash all fabric first. Batiks can bleed (and pre washing gets out any left over resist), and cottons shrink.

I just made a Falling charm quilt from batiks fat quarters and Kona cotton for the background. Batiks are a tighter weave.

I too have mixed fabrics in a quilt. Using batiks and regular.
I wash the batiks first, just because they can bleed. Then, once the quilt is finished, I use a "color catcher" in the wash. So far, so good.

Your question is whether the fabrics will shrink about the same. The batiks will shrink less than the other fabrics, and as others have said they might bleed, but the difference in shrinkage may not be significant enough to cause a problem after the quilt is quilted. (I pre-wash everything, like PaperPrincess.)

I mix all the time but I also use color catchers in the wash. Batiks design wise work as tone on tones.

Why not be safe and wash them first? I hate the stress of worrying.

Fabrics shrink differently when washed on their own. Once they are in a quilt with moderate quilting, the quilting "ties" the fabric layers to the batting layer. This moderates any shrinkage. In other words, a fabric that might shrink quite a bit will not be able to shrink more than the batting allows. That is why mixing batik fabric with other quilting cottons is not an issue provided the quilt will be quilted. Differing shrinkage rates can be a problem in tied quilts and quilts that have the quilting lines far apart (say, the 10" apart max that Warm and Natural allows).

Bleeds are a different issue. I do not prewash fabrics, but to make sure I don't get any unwanted bleeds in my quilt I always do the first wash in the largest front-loader at the laundromat (the more water, the more any dye bleed becomes diluted) and use Synthrapol which helps keep any loose dye particles in the water so they don't settle in fabrics.