These Art Spectrum boards look great so I have explored them, to see how they stand up to wet media. This post has the results on the white As board. I will post the blue board results later.
Photo 1. Collaged papers applied on the boards, one “White” board and one “Blue Haze”. The boards are acid-free and archival, with a thin layer of aluminium inside for sturdiness. They are light in weight.

Photo 2. I placed an acrylic wash with Atelier “Red Gold”.

Photo 3. Terracotta AS soft pastel pushed in with water and a brush.

Photo 4. When dry, the first layer of AS soft pastels are applied.

Photo 5. This detail shows how easily the pastel goes over the texture. I did not apply any further pastel primer over the collage before continuing to work with the soft pastel sticks.

Photo 6. Detail photo showing how beautifully the acrylic wash dried over the collaged paper, and how flat the collage element dried on this board.

Photo 7. “Mountain Pass” Pastel on collaged board. 16 by 20 inches (40 w by 51 h cms). The board is great to work on; didn’t buckle under the water/collage mediums; and took over four layers of pastel in the sky and foreground grass areas. These boards come wrapped in their own individual acid-free Krystal seal bag for transport and protection. They are sturdy enough to eliminate the need for a backing board.