There may not be an answer ... because all libraries (especially primary schools) prefer to use all white.
In this way, the library will not obviously give people a certain kind of books.
My company is a publishing house.
Information provided by Education and Manpower Bureau.
First of all, I don't know which library the color classification you asked belongs to, so I can only personally decide that basically many libraries use the same color on the book labels, while the Macao Civil Affairs Department Library will use ten colors to classify them: 000 light yellow 100 pink 200 blue 300 green apple color 400 orange 500 gray 600 dark yellow 700 pink purple 800 green 900 purple.