User blog comment:Mmpratt99 deviantart/In Need of Some Advice Once Again...And it Isn't a Creepypasta One/@comment-26399604-20170202140441

I also have a graphic novel in the works (first-timer as well ^ ^). I like how you have both. If the color shift is part of the story, then I don't see a problem with including both even if you're first timer.

How you want to relay that 'change' to the reader is up to you - there's a number of ways you can do it: you can directly tell us through some form narrative exposition, have the character themselves inform us through their dialogue/thoughts or interactions, or you could just have the reader figure it out every time you swap back and forth between color and B & W. It depends on your story and your style of conveying that information.

Personally, I don't think there is a right or wrong way as long you have your method and keep it consistent that way the reader can pick up your style and understand when and how they'll be receiving certain types of information.

There's a lot of nice free articles out there too that might help: +1

Some not so free: +1

+2

Hope this helps!