I can’t seem to get the reply button to work, but I’m replying to Clare Bureau post … “It is called Molotow Grafx Masking Fluid, and it comes as a pen-like applicator so you can draw fine-ish lines easily (mine is the 2mm size)”
I’ve been looking hard at these. Currently, I use the slanted end of some of my plastic paint brushes, which works well because I have several different sizes. I like Pebeo Drawing Gum masking fluid because it dries very quickly and peels off easily. So far, I haven’t had any problem with it on any paper I’ve tried (even non-watercolor paper) and even if I leave it on for days.
Still, the Molotow Grafix pen looks awfully handy. *sigh* I’m such a glutton for art products!