Library hidden room

[Tomek 18]

I have been trying to get to the hidden room, even watched some videos, but I cant seem to understand the trick. Can someone explain how to open that room?

[Walpurgis 501]

-"Light's End"

-Read?

-[Yes/No]

>Yes.

-"So kind was light to show us mercy,

That in its shade we festered heresy.

Twixt three stones, each shaded void,

Six pillars shone, their truth deployed:

Emerald, Crimson, Violet, Gold, 

Azure and Ivory seal as told.

Take heed of its prison, o ye foolish men,

For the blackest beast lies at light's end."

[Imperial 19]

Go to the sanctum where you saved Luna in 7th street. In the library where you found the codes to reach Luna there's a book (bottom left one I think) that starts with a list of colors. Or if you have the sanctum key you can go to the room on the left side of the sanctum and see a series of colored statues. In both cases, remember the order of the colors. Then go back to Beryl library in the room with colored books and activate them in the good order to open the door to the secret room