Used for some years to give good protection to antique (oil) paintings on metal but
meant to use on new acrylic paintings really, although I would use a thinner varnish on canvas as this is a very thick product like treacle rather than usual thin varnishes,
I found the best way to use this is a soft flat brush and quickly dab onto an area,
then brush out smooth before it goes sticky, it then tends to level itself out
& is touch dry in under 1 hour. I wash brush in white spirit.