So i let my friend practice using wella colour i wanted a natural dirty blonde thats close to my hair colour but is lighter. We chose wella illumina 7.81 and she mixed it with 9.0 to lighten the tone with 1.9% developer (i had ligjt golden blonde colour treated hair) The colour seemed to turn out well but now the next day in more light it looks too dark and turned rather ashy. I suit a more warmer and ligher tone and was wondering if anyone can advice on fixing the colour. Going to the salon isnt an option at the moment for me due to covid. i read that some people use lemon and conditioner. is this a safe bet? i also have 9.0 wella illumina left over (like 1/3, is it a good idea to use that as toner on top to make it lighter)? I attached photos of the hair and a photo of what the tone aim was