Marking a quilt

About a month ago I was marking a quilt for my son w/ bright blue, bright yellow, and tire fabric w/ black, white, and gray. Well, white worked on the blue but not the yellow. Blue worked on the yellow but not the blue. And, I needed both for the tires b/c that fabric was black and white. Dizzy yet?

Let me explain, I'm new to machine quilting, esp free motion quilting. I'm feeling more confident w/ every quilt but I must mark. I cannot sit down and start quilting w/out some line to follow.

Between finding the right marking pen/pencil and old ones running out, I spent about $20 on marking pens in a week. I bought a pack of 3 Clover pencils but their leads are too thick for the stencils and I kept wearing the tips off and had to stop and sharpen them a lot, while wasting more of the pencils. It was a shame b/c they marked very well.

Then I tried the Fons & Porter mechanical pencil and love the white - the graphite really didn't show up too well on the bright yellow. Those are the only colors F&P make. So, I went in search of the Sewline pencils that I've seen in the online shops. Finally found one 50 miles away. No blue but got white (b/c that was the only pencil tis shop carried) and both yellow and pink refill leads. Guess I'll have to order the blue pencil from the Fat Quarter Shop.