yellow mask

Here is a sentence said about F.S. Fitzgerald:

"He wrote about his world and himself, and covered it all in gauzy yellow masks."

Is yellow mask an idiom? What does it mean? Why is yellow chosen out of all colors?

Below is the context:

"You also seem to be asking that the book be more inspirational -- you would rather not have to face these "morons" -- but Fitzgerald did feel that he had to face them -- and himself in them. He wrote about his world and himself, and covered it all in gauzy yellow masks. There are, indeed, more than one or two lyrical and beautifully written passages here -- but there is as well a supreme feeling of emptiness, and the story ends with the narrator still looking for some meaningful truth -- something to make sense of the whole thing. Its a book that has always felt to me like the last vestiges of nineteenth century romanticism trying to stand up nobly upon a pair of drunken legs and falling down in its own vomit instead. No, it's not inspirational -- but meaningless and insipid. Not hardly."

Let me guess- Yellow mask is not an idiom but the writer's invention. Am I right?

Thanks.