I use acryllic paint all the time. On wallhangings, be sure to use the fabric medium, heat set, and wash in cold water.

It will effect the fabric feel if you put the paint on too thick, it gets stiff.

I would suggest you do a test piece so you feel how it is to be sure you want that on a bed quilt.
Also prewash the fabric, the finish that is often in fabric will keep the paint from settinng into the fibers

Almost forgot. When painting fabric use a fabric painting brush, the ones I use have a blue handle with white bristles. The bristles are stiffer than a regular brush. The stiffer brush pushes the paint into the fabric.

Thank you for all your replies, very useful!

sewgull:
Re stiff brushes - do you tape your fabric down when you paint it? I painted a line on fabric the other day and tried a stiffer brush than normal, but it seemed to distort the fabric too much. Maybe just a matter of practice.

dotcomdtcm:
Aren't Procion dyes transparent? There are a couple of darker/patterned fabrics that I'd like to paint on and I was under the belief that thickened dyes would disappear on colours that are darker or like in value. If I'm mistaken, great! I've wanted to try Procions for ages.

Salmonsweet,
Brushes for fabric are not real stiff, there is a brush just for fabric painting. Check local craft or art store, I will be glad to send brushes to you. I use regular acrylic paint adding fabric medium. About half and half of paint and medium.
Tape does hold fabric in place. I like cardboard as a backing support when painting. Cardboard can be a box, they are strong and don't bend easily.
Hope this helps. Please let me know how I can help.
Have a blessed day.

Oh thank you! Never thought of backing the fabric with cardboard, that should be really good. Will definitely give that a go next time. I think I can probably find fabric brushes online, my local shops don't seem to know about them (even though one sells setacolors!).

And thank you so much for offering further help. it's sooo good to know I can come back with more questions. :)

In fact I have another question!

I'm never too sure how to know when I've pressed a painted fabric enough to properly heat set it. (Scary moments when I've washed what I made...)

Is there a way to see or feel the paint change, or do I just keep going over it again and again and again until I reckon every spot has had several minutes? Or?

I don't know what type fabric paints you have in mind but I was given some dish towels that were painted with Tri-Chem paints 45 years ago. They were washed often and in hot water, sometimes with bleach. The fabric is wearing thin and the paints have faded but you can still see the design.

Use cotten setting setting. Be sure all paint is heated. Needs to be hot to the touch. Not necessary to press minutes.
There is slight different feel to fabric while sitll hot, not enought to notice.

Tri-Chem paints were great.

Thank you! :)

That sounds like some amazing paints. If the paint kind of lasts longer than the fibre.... well that's just amazing!

Just googled it, Tri-Chem have a website in the UK but only mail order, no online shop. I hadn't come across them before, do you happen to know why they don't seem to be around much? (I'm kind of assuming probably more difficult to apply or more toxic than modern fabric paints like setacolor or acrylics with medium, but what do I know...)