What's the evidence that the colors were added later?

[davidma]

I find it interesting that on You are not allowed to view links. Register or Login to view. there is a massive painting instruction that was obviously ignored. The most likely explanation to me seems that the painter simply forgot to paint it. However I think it does show, as others have said, that colors were added after the plants were drawn. If this was a week or a century after, I can't really tell. It does look like whoever painted it knew how to read the german/voynichese instructions, since they follow them elsewhere in the VM.