English to French Other Cinema, Film, TV, Drama technique du cinema

Au cinéma, je sais que "Blue screen" signifie un fond bleu, mais que signifie "Blue board", voire "Blue cardboard" ?
Je suppose qu'il s'agit aussi d'un décor bleu en vue d'être remplacé par des effets spéciaux, mais j'aimerais savoir comme traduire cette expression.
Deux petits exemples :
"And in these shots as well, the only thing in this frame with Gwyneth [Paltrow] was the phone, which was sort of nailed to a blue board. And there's nothing else in the scene with her. It's all blue that surrounds her. So we added the phone booth around her as well as other reflections inside of it."

"This shot here, we actually shot Giovanni [Ribisi] through-- We cut a hole through a piece of just blue cardboard, essentially to kind of conceal some light, so Eric could actually create a lighting effect on Giovanni. And in this shot here, again, there's nothing there."

Merci !