I'm always look for ways to combine my two passions - lettering and sewing. I began playing around with world city names in a loose brush style with the intention of creating a fabric to print at Spoonflower.com. I used sumi ink and a fat brush to hand-letter a bunch of city names and then arranged them in Photoshop to create an all-over design. This fabric is available for purchase here if it speaks to you!
I own several books on pattern design. They all offer something unique and have given me a lot of confidence to design fabric. I love A Field Guide to Fabric Design by Kimberly Kight for excellent instruction in using Photoshop and Illustrator. I would also recommend Mastering the Art of Fabric Printing and Design by Laurie Wisbrun. It's beautifully photographed and has a wealth of information. Spoonflower has also published a book to help anyone design fabric. It's called The Spoonflower Handbook.
Once I had the fabric printed, I used my favorite self-drafted tee to construct this luscious organic cotton. At $25 per yard, I wanted to feel confident about the fit of the tee. Even though that's a pretty steep cost per yard, having a designer tee is worth it for me (and Spoonflower runs sales now and again).
Let me know if you have any questions about designing your own fabric. I'll answer as best I can.