I love my slick writers! I've used them on photos but also on the Heidi Swapp ghost shapes. They dry very quickly. The colors aren't incredibly vibrant, but I think that'd be hard to achieve against any slick surface. They're a definite must have if you like to write on photos. I have also used them to "touch up" photos. For example, I had a photo where it got nicked in a spot. That part of the photo was black. I just took my slick writer to it and unless you look really, really closely, you can't even tell. Cool!
The Slick Writers pens will add an entire new element to your scrapbooking layouts and card making. The pens can write ON photos! Are you surprised? I sure was!
They write on slick surfaces (I said photos, you could also use it on vellum, etc) without risk of smudging.
The Slick Writers will soon become one of your most used products. :)
Medium point is my most used size. When you use them, it dries fast enought that it doesn't smudge. Work great on all slick surfaces. I like to use them on CD's also. Doesn't come off like a sharpie can.