I know this is splitting hairs, and that the assignment of red lettering is not an exact science.
I have read Red-Letter King James Version: Who is speaking in Revelation 21:5–6?
and Why would the speaker in Rev 21 not be considered Jesus?
Rev1:8 in particular refers to the speaker as "The Lord God". (Yes, I know it does not refer to "LORD GOD", how sure are we of this?).
To hard line attribute one utterance of this phrase to Jesus and the other to The Father would surely break the very fibre of the Holy Trinity, or introduce an inconsistency or contradiction. If we treat them as separate beings, one is surely a liar! If we treat them as a Trinity (single entity), there is no problem.
Is there an accepted difference of opinion on these interpretations?
Can we honestly, as humans, distinguish the members of the Holy Trinity in this way unless the Bible gives us an exact word?
I accept that the original Greek may differ from my NIV translation. To me, this simply and strongly confirms the closeness of the Trinity that I, as human, cannot fully comprehend. I would see no reason to have these texts either in red, black or any other color.