Archive for October, 2009

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Varnished Paintings Solve Uneven Surface Shine

October 31, 2009

One of the reasons to varnish a painting is that it can unify the surface quality. In this image of a recent painting of mine shown below, when you look straight at the painting it appears fine, but at this angle of reflected light the surface shine is uneven from matte to glossy. This matte effect is sometimes described as “sunken in” and a number of factors can create it.

Patchy shine on painting

The chief issue is related to absorption. Any paint media can have this problem, whether it’s oils, acrylic, gouache, or casein. The main constant with all of them is the pigment in the paint, but that’s not the only cause. The surface itself might be absorbent, like raw paper or gesso, or if you’re painting in layers then that paint surface may have varying degrees of absorbency. Some paints may also contain additives like surfactants, driers, or wax that can alter their shine. Some oil mediums, like stand oil, are glossier than others.

There are a number of ways to deal with this patchy shine. The best solution with some media is to varnish the painting. Unfortunately, I don’t recommend varnishing watercolor or gouache, since it can alter or damage the painting and can’t be removed, and some exhibitions require anything on paper to be framed behind glass anyway. Since it only shows up opposite reflected light, one option is to just hang the unvarnished painting in a location where you can’t see any reflection. That’s not always possible, however, and sometimes you have no control over where it’ll hang in a show or someone’s home.

Even though this effect happens with acrylics also, it’s a simple solution to just rub acrylic medium over the dried paint to even out the shine. You shouldn’t really do that with oils since it isn’t intended to be used like a varnish. Varnishes should be removable, but mediums aren’t, and can cause yellowing problems as they age.

Another option is to manage what paints you use and when. This may mean your initial layers can have more absorbent pigments, and the top layers use less or none of those. That’s quite a bit of trouble to go through just to avoid a shiny surface, and forces you to restrict your choice of pigments. Personally, I’d rather not concern myself with that and resolve the issue when I’m finished. Nonetheless, it’s a good idea to be familiar with your paint’s surface quality. In the images below you can see an example of various commercial gouache paints. I painted them on glass so they wouldn’t be effected by the surface absorbency. I recommend doing this test with all your paints in whatever medium you use.

Gouache on glass

paintshine2

Paint swatches


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In the case of my casein painting, it will be possible to safely varnish it. Right now it will be too fragile for any wet treatment, so I need to wait several months for it to cure. What I then do is add an isolation coat of permanent acrylic medium, and then add a coat or two of removable spirit varnish on top of that. That is how acrylics are varnished. If the work has to leave my hands before then, I’m forced to treat it as I would a watercolor and frame it under glass, or ask the buyer to return it later for varnishing.

The best solution for an oil painting is to varnish it also. A temporary varnish (retouch) can be applied after the final layer has dried which may take a couple weeks, depending on how it was painted. A retouch may not completely restore an even shine, but will do in the short term. Once the oils have completely cured then a final varnish can be applied.

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Three New Drawings

October 26, 2009

Here are some more drawings. The Equestrian sketch is actually about a year old, but the other two are recent. The kitchen sketch may be worked into a new painting.

equestrian
watchgame
kitchen

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How to Make Gouache Paint

October 21, 2009

Many years ago I learned how to make my own gouache paint since all the commercial brands I could find at that time were in small tubes that I used up rather quickly. Raw pigment was a bit more difficult to find back then than it is now. Anyway, here’s a sample batch I made recently of some burnt umber gouache.

gouachepaint2

It’s one of the simplest paints you can make, short of egg tempera. The only issue is finding all the ingredients. Essentially you just mix it all together and start painting. This pre-mixed binder can keep for several years, as will the paint.

gouachepaint4

BINDER:
2 tablespoons gum arabic powder
4 tablespoons distilled water
Pour water in a blender and add powder slowly while blending. Let it sit @1 hour.  A faster method is to heat the water to boiling, add gum slowly while stirring, let cool to room temperature. The blender method tends to give me a clearer liquid. Strain liquid through a cheesecloth if it’s lumpy.

3 ounces honey and water (1:1) warmed into solution
3 ounces glycerin
1 teaspoon oxgall
3 teaspoons dextrin powder
Mix together in a warmed bowl and add in gum arabic solution slowly while stirring.

1-2 drops preservative: Oil of clove, Thymol, or even concentrated Lysol will work

gouachepaint1

PAINT:
2-4 tablespoons dry pigment
1-2 tablespoons Binder
1 teaspoon Calcium carbonate as an optional filler to help bulk up thin paint

Place pigment on a large glass or plexiglass plate. I usually dump out about 1 teaspoon of pigment at a time, as shown above.
Make an indentation in the pigment pile. Add a small amount of binder solution and mix together thoroughly. A good target is half as much binder as pigment (1:2) but some pigments require less. Keep adding just enough binder to make a smooth paint to your liking. Any pigment that is difficult to get wet can be helped along with a teaspoon of grain alcohol.

gouachepaint3

Rub a small swatch of fresh paint on a clean spot of the mixing plate. Let that air dry for several minutes COMPLETELY (this may take longer than you think – give it 20-30 minutes or so.) Rub the dried paint with a cloth. If paint completely lifts then the mixture is too weak or there’s not enough binder. If the dried paint has cracks then there’s too much binder. Those can be hairline cracks, so I like to make a high-res computer scan of the dried paint to be certain.

If you find yourself using up those tiny tubes of paint, making your own paint can be much more economical, especially for expensive or hard to find colors, and you have more control over paint quality.

Please remember that pigments have certain health hazards and require careful handling in powder form.

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Two New Drawings

October 19, 2009

I’m showing two recent drawings, one in pencil, one ink. Both started as quick sketches and then finished later. Each on 8×10″ paper.

windowshopgirlbench

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Oil Paint on Drafting Film Test

October 17, 2009

To follow up some on an older post that explored using drafting film as a painting surface, I thought I’d test out a sheet of it for further oil paint tests. The results are mixed, but less than ideal.

Oil swatches on film

Oil swatches on film

Colors used: Grumbacher MAX ivory black, Lukas Berlin warm gray, Winsor Newton Artisan cerulean blue, MAX ultramarine blue, Holbein DUO red, Lefranc orange, W&N Artists naples yellow, Lefranc raw umber, W&N cremnitz white, Lefranc titanium white, W&N van dyke brown, DUO lemon, Artisan titanium, Artisan burnt sienna, Berlin primary yellow.

I took a piece of matte polyester drafting film made by Grafix, and painted swatches on it of various types of oil paints I had available. These colors have a range of vehicles from refined linseed oil, safflower, soya, and modified water-miscible oils. I painted both a masstone layer (right out of the tube) and a layer slightly diluted with odorless mineral spirits about 1 x 2 inches square for each color. I then let that dry for about 3 weeks.

Close up section

Close up section

In the end, all the oil types behaved about the same; although, some of the them, especially the Van Dyke brown, stained out very quickly after being diluted. The smooth surface of the film caused the thin paint to spread out quickly. I noticed very soon that all the swatches, even the faster drying pigments, took longer to become touch dry on this surface than they would on canvas or wood panels, probably due to lack of absorbancy. In fact, even now, the MAX black and Ultramarine blue are still slightly tacky several weeks later.

To test the adhesion, I first did a “tape” test where I rubbed some strong adhesive tape on the top of several swatches, and then cut through the tape and the paint film below. When I lifted off the tape, no paint was removed. Generally I would say that is very good adhesion, except that I then took a metal palette knife and lightly scraped the surface of each swatch, and it was extremely easy to remove paint this way all the way to the film surface. You can see this in the close up image above. That would not happen on a traditional surface like canvas or wood, or even paper.

I also tried some acrylic primer on this, and although I was able to scrape that off as well, it wasn’t quite as easily removed as the oils. It improved the oil paint adhesion slightly but not dramatically. Commercially available polyester canvas sold for artist’s use has a special acrylic primed surface that is heat-set and permanent (see for example Fredrix Polyflax,) but I don’t know how that’s done (possibly similar to BEVA.) I’m not much of a fan of acrylic primers for oil use anyway since I find the surface unpleasant to work on and rough on brushes. It also defeats the idea of having a surface that won’t be damaged by oils so it doesn’t need any protection.

The conclusion I’m making here is, compared to other surfaces, drafting film is less than satisfactory for painting with oils. It certainly will work, and the film itself is a much stronger and stable surface than the others. As long as it doesn’t get accidently scraped, it might hold up very well, but the permanent adhesion of the paint film is questionable. If that problem can be improved, I’ll reconsider using it.

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Gouache Painting: Asleep at the Beach

October 16, 2009

Here’s a recent painting I made in gouache media. It’s based on an old pencil sketch I had made of the main figure several years ago. The surface is Canson Montval paper that I’ve coated with shellac primer (still playing around with that.) On the left is a photo of the painting in progress.

In process

In process

Final painting scan

Final painting scan










I began the piece with a light colored (raw sienna) watercolor pencil sketch, applied a wash for the sand, and then worked out each figure.

It’s been awhile since I last worked in gouache, a lovely medium. I found I had to buy a few new colors that I didn’t have on hand, and one shortcoming of commercial gouache is it’s only available in small sized tubes. The largest size brand I’ve found is Da Vinci, which comes in 37ml tubes. Most of the others are much smaller, which can be a drag if you like to use lots of paint. Turner and Lukas make decent sized tubes also, and their paint handles well.

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Toned Grounds For Paintings

October 1, 2009
This subject of toned grounds came up recently in a discussion I was having with other painters, and I thought I’d make a post here about it. Many painters like to use a ground that has a different tone or color applied to it rather than the typical white ground that primer coats leave behind.
In the discussion I was having, an artist was wondering about the possibility of using a black primer instead of white. My reply was that doing so would tone down (lower the value) of most pigments. The only way to reach full intensity in that case is to use pigments that are very opaque. Conversely, transparent or semi-transparent pigments, which most paint pigments are, will take on a brighter tone as they optically mix with a bright or higher value ground. However, fully opaque pigments will appear slightly darker than they do naturally when surrounded by brighter values. Please study this graphic below for example:

Same red circles

Same red circles

All the reds in this graphic are duplicates of each other, and the larger outer ring is 50% transparent. Compare the two small circles on the left, however, and the two small circles on the right with each other. The red circles on a brighter value ground appear darker than the circle on a darker ground. In that discussion I was having, a comment was made that the dark ground intensifies the color. Actually, the color on darker value grounds appears with its natural tone. It isn’t made MORE bright; that IS its brightness. You can’t brighten a color in this way, but you can make it appear darker using this effect of surrounding it with brighter values. A color complement, in this case green, will add vibrancy to the color, but not change its brightness in the way that value will.

 

Greyscale & Complement

Greyscale & Complement

An interesting painter who used dark value grounds and outlines was George Rouault. It’s a dynamic effect and worth exploring. Something to bear in mind, however, is that as oil paintings age and the paint naturally looses volume, the pigments appear even more transparent as the oil looses its refractive properties. It may take some time for that to occur, but it’s a reason why many old oil paintings seem too dark now. (P.S. Yes, I considered posting a velvet Elvis example, but couldn’t bring myself to do it.)

Rouault "Old King"

Rouault "Old King"