Blonde to Brown

Ash browns can tend towards green over a blonde base and warm browns can tend towards pink or orange so I'd be careful either way, also over pre-lightened hair you might struggle to get a semi permanent out, if this is something you eventually want to fade you would be better using an Adore direct dye as they don't use any developers and the colours come out truer to the shade you choose even over lightened hair (though some can have a greenish fade! You can counteract this with warmer shades though as they are all intermixable and can be used frequently without causing damage!)

Ash browns can tend towards green over a blonde base and warm browns can tend towards pink or orange so I'd be careful either way, also over pre-lightened hair you might struggle to get a semi permanent out, if this is something you eventually want to fade you would be better using an Adore direct dye as they don't use any developers and the colours come out truer to the shade you choose even over lightened hair (though some can have a greenish fade! You can counteract this with warmer shades though as they are all intermixable and can be used frequently without causing damage!)

Ok, thank you! I'll look at Adore and see what shades of brunette they have. What about a color filler? I've read about using a red color filler before adding a brown shade (I'm not sure if the filler would make your hair red for a while or if you use the semi-permanent brown right after - I'm looking into that right now). Thank you for the help by the way!

I've not used colour fillers myself sorry, I went from a lightish orangey shade (which was bleached under that!) to a dark mahogany brown by first using Adore (I used Cajun Spice at first then eventually moved on to Mahogany) then after a while I dyed it with Wella Koleston 5.5  which faded fairly quickly to a lightish brown with golden tones where the hair was previously bleached so I keep this topped up with Adore Mahogany now to avoid further damage and just do my roots with the permanent as needed.

If you are thinking you may go back to your natural blonde after a while I would just stick to the Adore as you should be able to fade that by using dandruff or clarifying shampoos. It is hard to say whether your hair would fade evenly though, that depends on its porosity and condition really, everyone's is different!

Edited to add: the Adore dye will more than likely last longer where your hair has dye on it, rather than on your natural roots.

I've never used fillers either, but you can use adore dyes as a filler.