Secret Ingredient 2

It is always a major topic of debate between oil painters that what the best recipe of the medium.
My recipe is here;
Stand oil - 2parts
Linseed oil -2parts
Poppy oil -5parts
Dammar vanish -1part
This is stock medium and you need to add 1 to 3 parts of turpentine to the stock when you paint.
My work has sometimes very light/pale colors, so I am very careful about yellowing and aging and therefore using larger amount of poppy oil.
I am interested in your recipe and how do you ended up with the ingredient.
Do you want to tell me that?