Guillaume Fesquet is a French artist who works in visual development on animation productions. He currently works at Illumination Mac Guff in Paris, but in 2012, he worked as a trainee at Walt Disney Animation Studios. He posted some of the work that he made there such as these early Frozen concepts:
Here is Fesquet’s 2011 demo reel:
Guillaume’s studies have a strong sense of atmosphere. With simple digital brush strokes and savvy color choices, light appears to filter through murky particles and focuses attention on objects while dark areas frame the composition. Everything is done in service of strengthening the mood.