Are these opks +?

Sal • One 💙, one 👼🏻, one 🌈 🎀, by ovulation induction after 2 failed IVF cycles 🤯 | Hypothyroidism & lean pcos 🤨

Do the opks get darker as the LH surge increases or is it all or nothing (like it's either positive or negative?). Wondering if I am headed to surge, I am very due for O!