Dave -- I'm not trying to be pedantic, just clarify the terms. The term 'varnish' refers to a broad category of film finishes, not to a specific chemical type of finish. That is, lacquer, shellac, and polyurethane are all types of 'varnish'. Here's what Wikipedia has to say on the subject: "
The term 'varnish' refers to the finished appearance of the product. It is not a term for any single or specific chemical composition or formula. There are many different compositions that achieve a varnish effect when applied. A distinction between spirit-drying (and generally removable) 'lacquers' and chemical-cure 'varnishes' (generally thermosets containing 'drying' oils) is common, but varnish is a broad term historically and the distinction is not strict." (I quote Wikipedia because we all know there's nothing but truth on the internet.)
Thus, referring to Danish oil as an oil/varnish blend is not inaccurate. That's what it is. Of course, the description, while accurate, isn't all that useful. Each manufacturer has its own formula for Danish oil and there is a wide variety of combinations of oils and varnishes that are used in differing proportions. So,
Watco Danish Oil might build far less quickly than another brand, but that doesn't make one a true Danish oil and the other something else. Again, quoting Wikipedia:
"Danish oil is a wood finishing oil, often made of tung oil or polymerized linseed oil, although there is no defined formulation so its composition varies among manufacturers.
Danish oil is a hard drying oil, meaning it can polymerize into a solid form when it reacts with oxygen in the atmosphere. It can provide a hard-wearing, often water-resistant satin finish, or serve as a primer on bare wood before applying paint or varnish. It is a "long oil" finish, a mixture of oil and varnish, typically around one-third varnish and the rest oil." [Emphasis added.]
I am NOT saying ArmRSeal is or is not a Danish oil. I've not looked at its formulation. But, to the extent it is a blend of oil and a film finish, it's a Danish oil. It's also a varnish.