I'm a dedicated pre-washer ... especially with batiks, especially dark and or vibrant colored batiks. I'll wash all deep colored batiks at least twice in HOT water. Beginning with the 2nd pre-wash I'll toss in a color catcher, then just keep washing until the color catcher is clear.
For me, it's worth the extra effort as I love working with batiks. The weave is nice and tight, little fray, and if you are using it for paper piecing or applique you don't have to reverse patterns because both sides of the batik are pretty much identical.