Hi, I hope this isn't a silly question.
I've only very recently started using oil paint, within the last 4 months, to be exact. My painting instructor taught us how to mix our own medium using stand oil, distilled turpentine and cobalt drier. I've become very used to this but it can be expensive and a pain to mix.
I'm wondering if there are pre-made mediums that can be bought and if these are as good or better?