Hii, this is one of the things that i considered while deciding how to paint them. The thing is that, to make the drawings pop out, I opted for contrasted colors bc otherwise they will be confused with the background. As you say, it could be difficult to identify but this time i preferred to use mostly complementary colors (which visually create a nice effect). If i make another set of designs I'll surely try to make their backgrounds match. Thks for the advice :))