Painting canvas labyrinths is within the reach of any steady-handed person, given a few hints. Here is a concise summary of the considerations involved. This is based on our experience at Labyrinth Enterprises, LLC, where we have painted some 980 canvas labyrinths.

We use #12 cotton duck, a very densely woven canvas weighing 11.4 ounces per square yard. In fact, the paint rarely seeps through the canvas unless it is thinned considerably or concentrated in one spot. These same procedures may be used for other kinds of materials; however, it may be necessary to protect the surface beneath the fabric, as the paint may bleed through. Such a situation could be problematic if you use a method of painting such as a paint table, that involves moving the canvas, as the back of the canvas would also have wet paint. Thinner materials, such as muslin or nylon, usually require ink rather than paint, in order to maintain their flexibility. Such inks are often highly toxic, and require heat-treatment to make them colorfast. We are experimenting with an acrylic material on thinner fabrics, but don't yet have the final result that we are seeking.

Use indoor, flat, latex house paint, like you would use to paint a room inside your home. We get ours at Home Depot. Flat is important because semi-gloss or high-gloss paints get the gloss by having harder surfaces, which would be more brittle and prone to crack. Indoor is better than outdoor paint, as the latter has extra chemicals and is designed to flake slightly to endure weather.
To paint a 35-foot Chartres pattern we use about one and one-half gallons of paint. For a 24-foot canvas, two to three quarts. Smaller labyrinths obviously take less paint - our 12-foot personal labyrinths require less than a quart. This may not seem like very much paint, but remember that you are painting the lines, not the paths, and giving them only one coat. Therefore, you want to paint carefully and make sure you are covering the canvas evenly, without holidays (missed spots) or streaks.
If the paint seems thick and it is hard to get a straight and accurate edge, consider adding some Flowtrol. This is a paint additive used for spray painting latex paint. Latex cannot be thinned with water. Use Flowtrol instead. It breaks down the surface tension and allows the paint to flow more smoothly. At Home Depot it is found on a shelf underneath the spray painting equipment, or at least nearby. We sometimes use twice the amount recommended on the container. When I was painting ivy leaves and wanted the paint to have a more transparent appearance, I used half latex and half Flowtrol.
The color that you choose can also have an effect on the ease of painting. For some reason, we have always found red to be a difficult color. In general, the darker the color the better. Light colors not only don't cover as well, they increase the noticeable appearance of lapping. Lapping occurs when you stop painting long enough for the paint to dry. When you resume, taking up where you left off, you are obliged to overlap the dry paint slightly with the new, wet paint, so there is no gap. This gives that small area of overlap two coats of paint, which has a slightly different color or appearance than a single coat. Flowtrol helps retard the drying time a little.
Most of all, when you stop painting, stop in a line rather than in the middle of a petal or labrys (the wider area around a turn). This will minimize the lapping as much as possible. When stopping, put a piece of masking tape across the line and paint up to it. When you return, remove the tape, exposing the straight line at the end of your painted area. Use another piece of tape and tape across the dry paint leaving only the tiniest bit of overlap. This also helps to avoid lapping.

I have tried every imaginable painting tool, both mechanical and power-operated. Ultimately I decided that the best tool is . . . the paint brush. It holds the most paint, is easiest to control, gives a good line. I found that a piece of sponge gives a very nice edge, but doesn't hold or distribute the paint very well. I am told that Carl de Silva, who paints the labyrinths for Veriditas at Grace Cathedral, uses a foam brush. (It's not really a brush, is it? We should call it a foam paddle.) I sure don't know how he does it.
I tried power equipment to supply paint to the brush or roller, but was too difficult to control. So, I use a 1½-inch, slanted, good quality brush. At Home Depot I usually buy the Purdy brand. Go ahead, spend eight bucks for a paintbrush. You will also need some small artist's brushes to get into the fine corners.
Remember that a line has width to it. When we draw a canvas labyrinth, each line on the pattern is drawn with two pencil lines, parallel to each other, from two to three inches apart, depending on the design. Painting between these two pencil lines gives the ultimate line of the pattern. Having learned to paint with both my left and right hand, I paint along the edge of one pencil line, and then switch hands to do the same thing along the facing pencil line. When finished, these two painting strokes usually already meet in the middle of the line, so there is little filling in to do. However, I do usually make a last stroke with my brush to make sure the paint is smooth and evenly distributed.
The only other tool to compare with the paintbrush is the small, yellow, foam roller. This has a well defined edge (as opposed to wall rollers, which are ill-defined). My painter Judy Hopen is a master of the foam roller. She even does circles with them. I can't bear to watch her, it is too terrifying. However, she has found that many of the rollers come with a wobble to them. They just aren't made for this kind of precision. We used to throw away more than we used. Now Judy has a method of using an electric drill and razor to trim the edge and make it even.

Use a plastic shoe box or similar container to hold your paint can and brush. I put the paint into empty plastic sorbet cans, which have tight-fitting lids (holding about a cup of paint). A Tupperware container or refrigerator storage container would also work well. Put that container inside the shoe box. Thus, if you drip or spill, it will be inside the shoe box. You can also put your paint brush down inside the box.
Never, I say NEVER balance your brush across the top of your paint can when you want to stop painting for a moment. It is easily knocked off, perhaps onto the canvas. Just stand it up in the corner of the plastic shoe box. When you are finished painting, you can wash out the plastic shoe box with no difficulty. If using a foam roller, use a small half-size tray for paint, resting on a larger, flat serving tray. Be sure to avoid getting paint on the bottom of your container by getting too close to the line you are painting, which would make a mess.

If you have some small little drips or bobbles, leave them alone until they dry. If you try to remove them you will spread the paint and push it into the canvas. Once it is dry, scrape the off of the canvas with the point of a razor knife and use an eraser on what is left. For really big mistakes, get some canvas-colored paint and paint over them. It isn't a perfect solution, because matching the color of canvas is impossible. But it helps.

After practicing on paper or scrap canvas, start in an obscure place on the labyrinth, such as the fifth or sixth line on the upper right-hand side, away from the entrance. As you gain expertise, work your way to the more visible areas. You can paint the Chartres labyrinth in a smaller room by painting one section at a time. In order for the labyrinth to line up correctly when you assemble it, be sure to stay within the lines at the edge of the canvas (which is somewhat difficult, due to the bump made by the Velcro). If you have several people working, you can start with the fifth or sixth circle and have one person work outward while another works inward. Doing this in each quadrant, you can get as many as eight people painting at the same time without interfering with each other. Four or five people might be more manageable, however.

We have a painting counter, 13 feet wide, which allows us to stand while we paint. Each section of canvas is rolled up on a long piece of four-inch plastic PVC pipe. This sits at the bottom of the counter. The canvas is unrolled and pulled up over the counter. As we complete one counter's worth of lines, we then pull the canvas forward, exposing a new set of lines to paint. We use clamps to hold the canvas tightly in place. If the room isn't 36 feet long, that's OK, too. Just keep pulling the canvas as far as you can, then stop for the night while it dries. In the morning, roll up the dry section and repeat the process until the whole piece is completed. This is the system we use in our paint room, which explains why it usually takes six days to paint a three-section labyrinth.
Our Santa Rosa labyrinths are a single piece of material, 24 feet wide. For them, we line up four eight-foot tables, end to end, and pull the canvas across them, just as with the painting counter (see photo). Yes, three eight-foot tables would be just wide enough, but using four tables gives space at each end to hold lights, tools, boom box, etc.

During labyrinth walks, we like to use a runner at the entrance to the labyrinth, along which we place chairs on each side. People can sit there, remove their shoes, and then walk to the entrance. Labyrinths are often carried in canvas bags. You can paint patterns on the runner or the bags or other items used with the labyrinth to match the color(s) being used in the labyrinth itself.

In my experience, the volunteer with the least talent usually rushes right to the middle petals or the entrance to begin working. That's why I suggest starting in more obscure areas until you know who your best painters are. Assign them to the most visible areas.
We create a meditative space with soft music, asking the volunteers to minimize conversation. Not only does this help people's concentration, it makes the whole process a spiritual process rather than a gossip fest. If someone is a really bad painter, don't hesitate to stop them and assign them other duties (slicing the oranges . . .). Alternatively, you could have people put masking tape on both sides of the lines. This is time consuming but if done right can give good results for the less than steady-handed.

Make a ritual out of every step of painting and using your labyrinth. Bless the unpacking of the canvas, bless your paint and brushes, bless your hands that they may be steady. When the painting is finished, celebrate your work, dedicate the labyrinth, give people gifts or certificates marking their accomplishment.

Then, organize a dedication service before putting the labyrinth into use. Most of all, enjoy the result of your efforts. One of the greatest benefits of making labyrinths is the satisfaction that so many people will use them for their well-being.