Archive for the ‘Discoveries’ Category

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Paint Test on Tyvek Synthetic Fabric

June 11, 2018

Following up on the Tyvek fabric that I showed in my previous post, I wanted to show some paint tests on it using both oils and acrylic paints. In the photo above I painted a few sample swatches of each using different tools and methods. As a reminder, this is a 9×12 inch sheet of polyethylene fabric, “Tyvek” brand, mounted to mat board with acrylic gel.

For the oil paint on the left I used stiff a hog brush and soft sable, as well as a paint knife. Some areas were thinned with mineral spirits, or wiped down with a soaked rag. All of this worked out fine. There were a couple problems to point out, however. In the center yellow area, I used a stiff brush soaked with spirits, and scrubbed the surface hard. This caused the fabric to come unglued from the backing in that area (see the image below.) The other problem happened scraping lines with a metal paint knife. When I applied a lot of pressure it caused the thin fabric to tear. Although it is tear resistant, it’s not tear proof when using a metal tool. Otherwise, it works very well with oils. Since this surface is slightly porous, if your backing is a paper product I recommend sizing it properly if you will be using oil paint on this.


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In the acrylic paint section everything worked well with the range of tools I tested. This included the same type of brushes as used with the oil, a paint knife, a rag, and also acrylic paint markers (DecoColor & Molotow.)

Above are a couple things to point out about using acrylic paint. With a metal paint knife I was able to scratch through the paint surface rather easily after the paint had dried. It’s an interesting effect, but also shows that the adhesion is not perfect, but acceptable. This layer (left image above) of burnt umber was painted with a stiff brush in the top area, and again below it with water added. You can see how the water beaded up as it dried. When using a wet soft sable brush, this was less noticeable. The paint also takes a little longer to dry on this surface than it does on regular paper. After a minute or so I was able to wipe it off almost completely with a damp rag. In these closeups you can also see a small square grid pattern showing through from the fabric where the paint is thin. The square is only about 1 mm. It’s less noticeable in areas where the paint is more opaque.

Keeping these points in mind, I would still have no problem using this as a paint surface for oils or acrylics. Being synthetic, it wouldn’t have some of the aging or humidity problems that come with natural fiber canvas. It’s also very inexpensive, and comes in large size rolls. I may do another test using water-based paints of gouache and casein, as well as different drawing media, so stay tuned.

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Using Tyvek Polyethylene Fabric for Artwork

June 9, 2018

I recently purchased a large sheet of synthetic fabric that I wanted to experiment on as a painting surface. It’s called “Tyvek,” made by DuPont, and is a paper-like fabric made of polyethylene fibers. There are different brands out there that have different textures, and other features. The sheet I bought is 60×52 inches, and came folded in a letter sized envelope. I’ve seen rolls of it in larger sizes at hardware stores with “Tyvek” printed on it in large type. This was blank, and other brands in rolls may be also. This sheet is 43 GSM (grams per square meter) which is very thin, but it’s extremely tear resistant. Some other brands I’ve seen have a puffed up canvas-like texture, but this is smoother.

The folded sheet has creases, but I was able to mount it to a scrap piece of 9×12 inch mat board, and that removed the crease. In the picture above, the Tyvek board is on the left. I used an acrylic gel medium, and also painted the back of the mat board with a single coat to flatten it out when it dried, and then folded over the edges of the fabric to the back.

In this photo above you can see what looks like wrinkles, but it’s actually very smooth. These are fibers that leave wavy streaks of matte and sheen lines that looks something like wood grain. If you wanted to leave areas unpainted this would be seen, but an opaque coat of paint would hide it.

Here I’ve scribbled some ink lines to on the back to show an example of what that media looks like on this surface. Even though it’s soft to the touch, it does have a texture. You can see a grid of square lines running through it like a canvas weave. A thick paint layer would cover that, but thin washes would not. That’s not necessarily a bad thing, but something to keep in mind. I used sumi ink with a brush, a PITT brush pen, and a ZIG Millennium marker. Markers draw well on this in general, but water based inks may bead up some. Metal dip pens don’t work so well, tending to snag on the surface. Dry media, like charcoal or pastels work okay, but this is a little too smooth to be ideal for them. Hard leads of graphite or wax pencils don’t work very well either.

Once I figure out what to paint on this, I’ll show an example of how it performs with paints. I may just paint example swatches and nothing in particular, but I’ll still wait for a later posting.

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Testing Gesso Made from Cellulose Gel

October 1, 2017

A few days ago I was scanning the internet looking for raw art supply materials, and I came across a site that sold a gesso mix using methyl cellulose. This was “Eco Gesso” sold by Natural Earth Paint. I was surprised, but intrigued. I’ve used methyl cellulose (MC) and Carboxymethyl cellulose (CMC) as art mediums before, but not in this manner. (Here’s a link to a previous post using MC mixed with oils.) I’ve made gesso before using rabbit skin glue (RSG) or casein for many years. My first reaction to one of this type was that MC or CMC would be too weak by comparison to serve as an effective foundation for painting; however, being naturally curious, I decided to try to make some of my own, and test it out. A $30 kit from Natural Earth sounded like too much to pay for experimenting.

I’ve read that CMC has a stronger bond than MC, so I took a teaspoon of CMC powder, and converted it into a gel by adding eight teaspoons of distilled water.

Next I added water to thin this out, and solids to make the gesso. That’s the gesso in the metal bowl.

I took a scrap panel I had, 8 x 10 inches, patched it up a bit, and applied the first thin coat.

Here’s the finished panel with 8 coats.

I had to make 3 different attempts at this. The first batch of gesso I made, using the same ratios of CMC gel that I use with either RSG or casein was too thick, and the end result on the dry panel was dusting off too much, leading me to believe the glue was too weak to hold that much gypsum. This panel is the second attempt, which had 25% less solids, but the same glue strength. It went down very smoothly, and although it didn’t powder off as badly as the first one, it still was rather weak. I could wipe the surface and get a powdery residue. I made a third attempt by using less water in the glue, and it didn’t brush on as smoothly, but still dusted off.

In summary, this gesso is much weaker than those made using RSG or casein, just as I first suspected. However, it’s not completely unusable. It’s like painting a fresco. Wet paint will turn pastel from mixing with the surface powder, but still hold. You can see the difference of this burnt umber paint on the CMC gesso panel compared to the same paint on a scrap piece of watercolor paper. If one doesn’t mind that desaturation of color, then it can work acceptably with either water based or oil based paints. The CMC powder can be found online very easily. I bought mine at a local ceramic supply store. It doesn’t have to be heated or refrigerated like the other glues, but can grow mold. A drop of preservative, like thymol, will prevent that. Personally, I’ll stick to the other glues. They make a stronger surface and are more versatile, but it’s good to know there’s an alternative.

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Casein Glue Made from Instant Milk Powder

September 23, 2017

I was at a friend’s house recently, and as we were talking about my experiments with making casein, she complained that she had some dry “instant” milk powder she had bought for her young son, but he didn’t like the taste. She let me take it home to experiment with, since I had never tried making casein from a dry powdered milk before.

This particular brand from Saco Foods is like other commercial milk powders I’ve seen at grocery stores “fortified” with vitamin A & D (and sometimes E) so I’ve always avoided using them, but there are other brands on the market that don’t have anything else added. It could be convenient and more economical to make casein from this if it works out well. It did. Here’s how I made it:

I followed the instructions to re-hydrate the powder by adding 3 3/4 cup of water (distilled) to one package, 3.2 ounces, of powder. This made about 4 cups of milk. I used a blender to mix it well, and set it in the refrigerator for 24 hours. The next morning, I poured the milk into a pot, and heated it on the stove to @150 degrees, turned off the heat, and added 1/2 cup of distilled white vinegar. Stirring for a couple minutes it congealed into a ball of casein. So far so good. I removed the ball of casein and filtered the liquid through cheesecloth to catch as much extra casein as possible, and then tore up all the casein into small pieces so it would dissolve more easily. In the picture below is a bowl of about 2.5 ounces of casein from the 4 cups of instant milk.

I rinsed the casein in clean water a couple times to remove as much of the vinegar as possible. Next I placed it in a 12 ounce jar, and I diluted 2 teaspoons of borax in 1/2 cup of distilled water that I heated in the microwave for about 20 seconds, and then added to the casein. This will turn the casein into a glue gel.

After about 6 hours or so the casein had started to transform into a gel, but was still a little lumpy. At this point I stirred in a drop of thymol to act as a preservative, and let it sit for awhile longer. After about 12 hours it had transformed into a very thick and stiff gel, about 1/2 cup.

Comparing this to other casein glue I’ve made I would say the gel from raw milk is more opaque, and gel made from dry casein powder is has a slightly darker amber tone. It does feel slightly sticky, so I would guess it will work just fine for my needs in making paint, gesso, or fixative. Very encouraging.

I’ll check out a few local grocery stores to see if I can find some instant milk powder that is unfortified. If not there are plenty of brands on the internet I could order. Here is one from Bob’s Red Mill, for example. The label says it has 0% vitamin A, so no Palm oil is added, and no vitamins D or E. The vitamin C is a natural milk component. From that 22 ounce packet I should get about 4 cups (32 ounces) of casein gel. If I remember correctly, I can get about 16 ounces of gel from a gallon of fresh milk. In powder form, the milk can be stored up to 2 years.

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Shiva Casein Paint Test Update

July 24, 2017

To follow up on my previous post, I had found that one of my Richeson/Shiva paints, Cadmium Green, transferred to a dry paper towel with just some light rubbing after the paint had dried. Now I wanted to see if other tubes I owned had this same problem. They do.

This picture shows a sheet of paper on which I painted 1 inch swatches of all the different tubes of Shiva paints I have. The paper towel at the bottom shows pigment from each swatch that transferred over. I did not dilute the paint at all with water, and did not apply the paint too thickly. All of the paints smeared easily when rubbed, some more than others, with the sole exception of the Raw Sienna. The ivory black in particular smeared very badly, and even after a day of drying felt to have a weak paint film.

Since all of the paints are old, in some cases decades old, I asked around to other people who used these paints if they could test any tubes they might have that are newer, and see if they had the same problem. I heard back from a couple people. One person had some Richeson caseins that were only months old, and found they had the exact same pigment transfer problem. The other artist rubbed the surface of paintings he had made that were at least 3 months old, and said no paint at all rubbed off. What this tells me is it might be possible that if the paint is allowed to cure for awhile longer, the pigment will adhere better and not rub off. This strikes me as a strong possibility. So, I think I’ll do a new test on paint swatches that sat undisturbed for a month or more, and then see if any pigment rubs off.

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Comparing My Casein Paint to Shiva Brand

July 22, 2017

I wanted to follow up on my previous post where I made my own casein white paint, and see how well it compares to tubes of the Shiva paint I had, and discovered something interesting. I used the paint swatch I made testing my paint on a sheet of Strathmore textured “Art Paper” 65lb.

I painted a small swatch of the Shiva titanium white, undiluted, next to the swatch of mine I had made. It may be hard to tell in this photo, but I noticed their white has a slight off-white yellowish tint to it that mine does not. I let this dry for a day, and came back and gave both a buffing with some colored fabric, and saw no transfer of pigment from either swatch. Next I placed a small piece of cellophane tape over each one, rubbed it, and removed the tape. Both transferred some paint, but more paint came off the Shiva swatch, lifting almost all the paint from the paper. The casein binder I used to make my paint was over a year old, so later I’ll see if a fresher batch performs better.

Since that tube of Shiva white is many years old, I thought I’d test a newer tube of Cadmium Green that I had to see if it performed any better. Rather surprisingly the pigment adhesion was worse. I let that paint swatch dry for about 3 hours, and rubbed the surface with a paper towel. You can see quite a bit of pigment rubbed off. The tape test pulled off quite a bit of pigment also, and the way the pigment transferred was not in sections of paint, but powdery like what I saw on the paper towel. This tells me that the adhesion on this tube of Shiva paint is poor. Granted, it’s about 5 years old or so, but it shouldn’t come off this easily. I have commercial tubes of gouache that adhere better than this. I hope the newer Richeson brand of Shiva adheres better. Now I want to test the rest of the Shiva paints I have. This is not terrible, but surprising. This paint adhesion is not much better than soft pastel.

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Plaster Coated Paper for Gouache Paint

May 4, 2017

As I get ready to prepare the surface for my new painting, I wanted to test out a ground to use especially for the grass area I’ll be painting. I’ll be using a large sheet of illustration board, and coating it with a thin ground made with spackling compound.

Spackling is a paste made out of (typically) calcium carbonate, silica, and glycol. You can find it at hardware stores, and it’s used for filling small holes and cracks in walls prior to painting. It can be thinned with water. I’ve added a small amount of acrylic medium to improve the adhesion and make it more flexible. In the picture above, I’ve drawn an area in pencil to show the rough texture it makes. It feels like a fine grit sandpaper. I applied just one coat. It creates a nice paint ground, but can lift if you use a very wet wash. Adding acrylic medium helps prevent that.

The main reason I’m using this particular ground is to allow me to lightly scrape away paint layers. You can see the marks I’ve made on the small test area of gouache paint in the picture. It will help me create a more convincing grass texture. The tools I used here are a bamboo pen and a solder scraping brush. The bamboo doesn’t dig too deeply into the plaster, and the steel brush gives a fuzzy, random scratch. I’m using various commercial gouache paint, as well as a couple of my own. This should work well for me.

UPDATE:
I’m adding a closeup of the painted area to show the scratch marks better.