The expression BIBLE-BLACK

I read the article “start or begin?” and I found the expression BIBLE-BLACK.

«To begin at the beginning: It is spring, moonless night in the small town, starless and bible-black…»

I would like knowing the meaning of such an expression.

Regards.

The words were written by Welsh poet/author/playwright Dylan Thomas. At the time when he was writing all Welsh chapels and churches, and many Welsh homes, had a big leather bound Holy Bible. The leather was usually black in colour.
Use of this expression likens the colour of the sky to the perfect black colour of those leather bound Bibles.

Dear Beeesneees:

Thank you for this cultural explanation which was very interesting.

Regards.