Watercolor Supplies, Tools and Surface...

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PICKING A PALETTE
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escoda travel or kolinski series 7 sable
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BEST: STRATHMORE HEAVYWEIGHT ILLUSTRATION BOARD PLATE & VELLUM
To the Left are examples of masking fluid often used in Watercolor to seal an area before washes then remove to reveal white paper.
I firmly don't recommend the blue ones, as they can leave a tint on your paper---actually I don't use Masking Fluid at all. I opt to control my whites if using only watercolor. If using Mixed Media, I will use an acryla-gouache white for specular highlights. 

Toned Paper for Gouache

Gouache

ACRYLICS

The two main brands that come to mind are Golden and Liquitex. Both brands carry a variety of Thin to Heavy Body for your preference in working. Golden is highly regarded for color and steadfastness but both brands are more then sufficient.