Colorization - what was it's purpose?

[Aga Tentakulus]

       
And once again.
When the red ink (text) was added, the author drew extra lines. You can see that more vertical space was allowed for the red text. The reason it’s larger and red is because it was important.
No one would draw lines for someone 200 years later.
Since the other writing ink is the same as the one in the circle, it allows for only one author (same ink).
Therefore, everything was done at the same time, and that also applies to the same red in the drawing next to it. Whether the book was bound or not.
So why not the blue at the same time as well?
Is everything clear now?

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