In watercolour painting the whites are not generally added as paint but are reserved areas of the paper that are not painted on.
Top 17 Art Tools And Materials for Drawing And Painting And Their Functions - Artful Haven
masking fluid — Lorraine Watry Watercolor Blog, Instagram, and - All things watercolor — Lorraine Watry Studio
Pour Painting Supplies Guide by Olga Soby I Fluid Art Supplies – Olga Soby Shop
My Favorite Watercolor Painting Supplies — Forest Culture Design
Supplies You Need to Get Started With Acrylic Pouring (Beginner Checklist)
MASKING LIQUID REFILL - easy and clean masking!
Pour Painting Supplies Guide by Olga Soby I Fluid Art Supplies – Olga Soby Shop
Spotlight on Gesso Primer - Art Supplies materials and equipment
Watercolour Painting for Beginners: What You Need to Get Started - Jackson's Art Blog
Pebeo Drawing Gum, White Drawing Fluid
Using masking fluid - Jackson's Art Blog
Pour Painting Supplies Guide by Olga Soby I Fluid Art Supplies – Olga Soby Shop
Watercolor Masking Fluid - DANIEL SMITH Artists' Materials