Well, this drawing was sort of special, since there's no visible lineart layer. Of course I used one during my process, which simply was the original pencil drawing. I used to make ink linearts in Photoshop, but lately, I found it more satisfying to just use the scanned picture I drew.
Thanks by the way:) And if you need any help with layers, feel free to ask, even you don't work with PS. I believe Sai's layers work the same way as well.
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Pfft, I named them because it was weird to call them "purple-haired-giant" and such :D