My first batik quilt blocks seemed to be stretching. When I had the quilt longarm quilted, she seemed to have the same problem. I was using all Robert Kaufman batiks. Any suggestions?

Did you use starch? Also she could have pulled them a but taunt I have never long armed but when I have quilter on my own it seems to be fine.

I work with batiks a lot and I've never had a problem with stretching. In fact, that's why I work with them. I never starch batiks either. Were they cut on the straight of grain? Were they all the same type of batiks? I've found I can't mix ConnectingThreads batiks with others because CT batiks are a thinner weight; I noticed they didn't press as crisp or hold the triangle shape as well.
Guess I'm not much help--just offering some thoughts.

I love batiks, a sharp sewing needle is a huge help due to the thread count a dull needle can cause problems such as a dull blade on a rotary cutter.

Must have been on the bias, because batiks are very very stable along the grain.

what kind of blocks did you make? were there alot of bias edges? batiks are generally a very tight weave-stable fabric- they don't tend to stretch much-unless cut on the bias-which gives the most stretch on any fabric.
for next time around-if you have bias edges on the outside of the quilt- before sending to the long-arm quilter it is best to run a stablizing stitch all the way around the outside edge of the quilt- this will stablize it and keep it from stretching out of shape as it is quilted- it is also a good idea to do if you have alot of seam edges on the outside of the quilt instead of straight borders (keeps the stitches from being pulled apart as it is rolled on the frame.
i did one time buy some batiks from joannes that stretched if you looked at them wrong- they were horrible to work with- and i wound up saving them for some other project-not a quilt- but normal batiks are very stable - tight weaved fabric- have you talked to the quilter-to find out what she thinks caused the problem?

just like mine I HATE THEM, a dear quilter on here suggested wash again in water ,towel dry and don't iron ------it worked ,the fabric went back but had PREVIOUSLY stretched inches ,I was disbelieving------------HORRID.