Covino Glaze Medium over Liquin for portraits?

[Steven Sweeney]

I can't speak to Covino medium, which I haven't used, but I'd offer a few comments, some anecdotal, about other things you mentioned. More-experienced contributors can correct me if I'm out in left field. (Not that there's anything wrong with that.)

I've never encountered any two oil artists who use the same formulas for or methodologies in employing mediums, but I find that an almost universal attitude is "less is better". It is the obvious characteristic of oil paints that they already have oil in them (!!), and you should be able to create paintings with complete molecular integrity using no additional oils or solvents at all. Mediums have various uses -- such as increasing or decreasing drying time, or their obvious necessity in glaze applications -- but they're most often used simply -- and sparingly -- to enhance the "spreadability" of the paint. Manufacturers don't carefully formulate their paints with the intention that those formulations necessarily be altered prior to use. It's important to remember that anything you add to paint changes the ratio of pigment to binder (oil or resin); to the point, it dilutes the pigment.

It sounds to me like you're using a very great deal of solvent and medium in your paintings. Indeed you say you coat the canvas with medium before you even start painting. Yikes! Sounds like you handicap your efforts by beginning with an oily, slippery surface. Also, medium (oil) is "fat", and "fat" belongs on top of, not under "lean" (paint to which no oil, or in the case of a toned underpainting only solvent, has been added.)

Most painters I've worked around do use turps in their pigments to tone a canvas or possibly to lay in an underpainting, but I don't think turpentine has any use or place on its own in a painting after that. (I realize that some medium formulas require addition of "some" solvent.) As a solvent, turpentine returns paint to its premanufactured forms, most notably separating the oil binder from the pigment, which was powder before and, according to some, will become powder again under such conditions. One instructor even takes somewhat perverse competitive delight in the fact that other painters use turpentine in their paintings, which, he says, means that those paintings will self-destruct in a few decades or less, while his own will still be sound and viewable. I don't know if that's true and I don't know if that instructor knows, and I won't be around long enough to discover the truth.

You refer to the use of medium for "opaque" passages. I wonder if you mean "transparent". Opacity would be compromised at least to some degree by use of medium or solvent.

As for what you "lose" by not using retouch varnishes, I would say "nothing", unless you're confronted with one of these narrow situations: the color in some areas has "sunken in", become matted in appearance and difficult to assess in relation to other areas of the painting; or, a layer of paint has dried, in which case, for subsequent layers to adhere, retouch varnish can add some "tooth" to the surface. Otherwise, I'm aware of no sound reason to introduce that additional material into your paint surface. I've sometimes read that painters will apply a coat of retouch varnish before delivering a piece, because it's too early to apply straight varnish. Personally, I would be disinclined to send a painting out with a fresh coat of a solvent-based compound. I have trouble understanding how that can "protect" the painting in any significant way.

Lastly, Liquin. Mostly as a matter of convenience, I use Liquin exclusively when doing plein air landscape sketches. I just prefer not to use valuable time and space schlepping a bunch of solvents and oils around in my French easel, which is already full and heavy enough. Indoors, I tend not to use it, though many wonderful painters use it exclusively for everything. I would note that Daniel Greene, aware that many of his vocational compatriots use Liquin, nonetheless has chosen not to (at least up until about a year ago), simply because the formula for it is proprietary and secret, and Greene says he's not comfortable putting something into his paint if he doesn't know what it is.

No doubt others have their own experiences and observations.

Steven