When you need to add a pattern onto fabric for a costume to make it screen accurate, you have so many options. Oberyn Martell’s robes from Game of Thrones come to mind. You can embroider patterns on, use appliques, or paint directly on the fabric. I often choose the latter because it’s less of a pain and works on just about any kind of fabric. Caffeinated Crafting recently posted an overview showing how different painting methods – airbrush, paint brush, and sponge – work on cotton fabrics using a freezer paper stencil. His notes on using a paint brush (my go-to):
Paint Brush – Start outside the stencil and drag the paint in toward the middle, this will prevent paint from getting under the stencil
Cheapest and most intuitive
Can do tiny details if a smaller brush is used, also works well for free-hand
Can leave a heavy paint layer if you aren’t careful
Have to be careful around the edges to not push paint under the stencil
Can be labor intensive
Read the complete tutorial at Tumblr.