Using a white gell pen can give irregular and disappointing results.
Time to try something different....
Using a Japanese screw punch/book binders punch with a tiny hole attachment, I randomly punched tiny holes all over the background, then mounted the image onto white card stock and Hey Presto!!! Regular shape, white snowflakes showing through the blue background and no blue ink bleeding into the white gell pen. I also added a little glue and glitter into each holes for sparkle.
