Hi I just wanted to know, if I have been using a majiblonde 900s colour on my hair as full head, would putting majireal 7.4 as low light give it a nice copper tone and would it hold for long?

If your hair is a level 8 (blonde) and you apply Loreal Mjirel level 7.4 (copper blonde), it will make you hair a copperish blonde color.