I have a book, THE ARTIST'S HANDBOOK OF MATERIALS AND TECHNIQUES, by Ralph Meyer, left over from my art school days. In it Mr. Meyer devotes several pages to the history and different types of linseed oil, including boiled and stand oil. He evaluates their drying and aging properties and how they pertain to painting but much of the info would be useful here, such as color changes due to age and elasticity.
Much like olive oil, the best linseed oil (which is pressed from the ripe seeds of the flax plant) is what is termed "cold pressed", lower yield but vastly superior quality. Hot pressed is subjected to extreme pressure & heat, inferior quality.
Google "cold pressed linseed" and many art supply stores now carry it.
According to Mr. Meyer, boiled linseed is a misnomer, it is simply heated with driers to thicken it.
Stand oil is linseed heated to 525˚- 575˚ and held there for several hours. An internal change takes place, a polymerization, which thickens it Nothing is added to or lost from the oil. It yellows less with age than raw linseed. I imagine the quality of stand oil would depend on the quality of the original linseed from which it was made.
BTW, the copy of THE ARTIST'S HANDBOOK OF MATERIALS AND TECHNIQUES I own is the 5th Ed., it's still the latest edition. Earlier editions are available on Abebooks for as low as $1.
