How should I treat my new batiks before sewing? TIA

If the final product will be washed, then you need to treat them before sewing to avoid problems later.

What should I use to treat them?

Prewash - I do this with a white piece of calico in the washer to check they don't run. Then press and stach. I use a fine thread - YLI 60 wt and a 70/10 needle - a bigger needle leaves a hole. I adore working with batiks, I find they behave so nicely compared to regular cotton fabric, due to their higher thread count. Plus both sides are up, so I don't have to worry about that either! LOL Besides that, the same as regular cotton.

Sorry Marie, we were posting at the same time - I've read lots of stories about batiks bleeding - including on here - but I've only ever had one bleed on me, years ago, a dark blue. I washed and rinsed a couple of times more and then it was fine. There are products Retayne I think it's called but I've never had to use it so can't comment.

I snip a bit off, and check them for color fastness in hot water. That determines whether I use Retayne or not :D:D:D

Yes, Retayne is the product that will set the color if it is bleeding. I have a blog post that explains the difference between Retayne and Synthrapol:

http://andicrafts.wordpress.com/2010...hich-is-which/

Most lines of batik do not bleed at all. I test anything I am suspicious about by snipping a small piece and dropping in a clear glass of water. Should be no color drifting off the piece. Also rub it against white fabric to make sure there is no "crocking". Although most batiks do not bleed, that will not be any comfort to you if one does bleed and you don't catch it before it is in the quilt!

I'm a confirmed pre-washer of all fabric, batiks especially. I wash most of my batik colors in the machine (in hot water), but my reds, blues, purples and blacks I wash by hand in hot water in the kitchen sink so that I can see when they've stopped bleeding. I've had these colors bleed through 2-3 hot water washes. After that I dry them and either fold and store, or starch iron and use.

Batiks and starch are great companions. If I use a good amount of starch on a batik I find that 'finger pressing' seams take and hold really well. I also like a well starched batik to prevent slippage in the machine and nice crisp cutting.

separate lights & darks and wash them- then dry them-
then press them- then cut them up and create something beautiful!