When you color using Stampin' Up! Blender pens and inks you can use watercolour paper or Stampin' Up! Shimmery White - it holds up better to ink then regular Whisper White so it doesn't bobble as easily as you work - allowing you to get a deeper colour on your image :)
Remember you need to use Stazon - or another permanent ink as the blender pen and inks are water based - so the black ink will run unless it's a permanent one:)
Don't be afraid of Stazon - you can use it on your stamps - the main issue is that it requires Stazon REMOVER to remove the ink - and that can be harmful to your stamps.
Just clean the stamp with stazon remover then thoroughly clean that off with regular Stampin' Mist cleaner - you are then good to stamp again!