Pastello bianco literally translates to "white crayon". It's a seemingly simple phrase that holds a deep, nostalgic, and somewhat melancholic meaning in the song.
The singer talks about writing all his secrets with a white crayon on his diary, hoping someone would come and color them in. This metaphor beautifully conveys hidden feelings, unspoken desires, and the longing for someone to truly see and understand his inner world, making it a unique and evocative choice.
The whole song hangs on one image. "E scrivevo tutti i miei segreti / Col pastello bianco sul diario" (And I used to write all my secrets with a white crayon in my diary): white on white, invisible, written for someone who never came to read it. The line right after it explains everything else, "Speravo che venissi a colorarli" (Hoping you'd come and color them in). This is a friendship that ran from the first year of school onward on one rule, which was to never say anything out loud. "Il nostro vecchio gioco era di non parlare mai / Come due serial killer interrogati all'FBI" (Our old game was to never talk, like two serial killers interrogated by the FBI). The joke is funny, and then it isn't.
Every other feeling here gets smuggled inside something smaller. Crying is demoted to an optical illusion, "Stavo solo togliendo il mare dai miei occhi" (I was just taking the sea out of my eyes). The two of them sit in a bar and argue about the bill instead of about the thing they are actually losing. Even the ending is too heavy to name, because "un addio suona troppo serio" (a goodbye sounds too serious), so what comes out is "bye bye". What he kept from the whole friendship is absurdly small and exact: "Tu mi hai insegnato la differenza / Tra le ciliegie e le amarene" (You taught me the difference between cherries and sour cherries). The other person is still stored away somewhere, "la mia password del Wi-Fi" (my Wi-Fi password), and he signs off with something generous and a little wounded, "E ti auguro il meglio, i cieli stellati" (And I wish you the best, the starry skies).