Black and white have been the colors used for most reading materials in the history of English speakers. This color combination helps us to read (and comprehend) more quickly. The expression "It's all there in black and white" can mean that something is very easy to see, that it should have been noticed, and / or that it should be easily understood. It's often used in reference to some sort of dispute, perhaps indicating that one party should have noticed or understood something that they claim to have missed. I hope this helps!

It means that it is very obvious or apparent.

Another word, it's clear as a day.

I got it. Thank you, everyone.

意味は「とても分かりやすい」