Image Transfer Techniques for Murals
One of the most important steps in painting a mural is getting your image transferred accurately onto the wall. This can be very tricky since it’s impossible to paint a large scale image the same way one would paint a smaller piece.
Image transfer techniques are an essential skill when tackling a mural project. Traditionally there were two methods for transferring an image, pouncing and gridding. These techniques are still used today along with a few new digital ones.
1. Grid — This is the most rudimentary where you put a grid on your picture. You then take that same size grid, put it up on the wall, and go square-by-square to transfer your image. The smaller the squares in the grid, the more accurate of a transfer you’ll get of the image.
2. Scribble Grid — This method became popularized once artists started using Photoshop. It begins by painting unique looking scribbles over the entire wall. Then you have to get far back and take a very straight photo of the wall, called an orthogonal angle. It’s important to get far enough away that none of the lens distortion is causing any distortion in the image of the wall.
Once you have your photo you superimpose it on top of the mural image that you're trying to transfer with a program like Photoshop or Procreate. Then you essentially use the individual scribbles like a grid. The advantage of a scribble grid is that it's easier to put up than a traditional grid because you don't have to have a chalk line or a tape measure. You're literally just drawing whatever comes into your head, as long as the scribbles don't look exactly the same across the piece.
3. Pouncing or Electro Pouncing — Essentially you're using paper to transfer your image. This is the technique used by all Renaissance muralists and it’s the oldest way of transferring murals that we know of.
For example, let’s use Michelangelo’s, The Creation of Adam. Michelangelo knows, for instance, that the figure of Adam is nine feet tall. So, what he'll do is take a finished sketch of the section that he wants to work on, and put a grid on it, and then draw that image full size on a piece of paper.
He might have three pieces of paper that are all attached together to create the figure of Adam. So he's now got a full size line drawing of Adam that's called a cartoon. (The original term for cartoon stemmed from line drawings that were used for murals.) From there his assistant would put the drawing on a piece of felt and take a needle and poke holes along each line in the cartoon. When finished he’d put the piece of paper in its place on the mural. Then he’d take a bag of charcoal dust and pat the lines. Which is why it's called pouncing. The dust goes through the dotted lines and when he takes off the piece of paper, a dotted image outline of what he needs to paint is left behind.
In modern times we have what’s called an electro pouncing machine. Instead of trying to draw a full size cartoon based on a grid, mount a piece of sheet metal to a wall. Then using magnets, put a piece of blank paper on top of the sheet metal, and project the image onto it at full size. Using an electro pouncing stylus you draw the projected image onto the piece of paper. Because the paper is mounted to a piece of sheet metal, the stylus causes an electric arc that punches thousands of tiny holes into the paper as you draw.
Once you've drawn the entire image, say it's 10 pieces of paper that you've done section by section, number them and roll them up. Transfer the paper to the mural in order, and then use graphite powder to pat along the lines, essentially using the same technique from Renaissance days.
4. Projection — Straight projecting is the fastest and the easiest method. It requires the least amount of work but it does require you to either have a super high end short throw projector or have enough distance from the wall in order to get the full image projected onto it.
With a lower end projector it's important to have enough distance from the wall in order to get the full image projected. With a bigger wall it helps to separate the wall into quadrants and then project each section so that you don't have to have enough distance for the full 40 foot image. Instead you’re projecting four 20 foot images.
That covers the four main ways to transfer an image onto a wall in preparation for painting a mural. There are some artists who still freehand their pieces but it’s not recommended for speed or accuracy. It’s important to remember that these techniques were invented to address the unique problems involved in painting oversized images since they can’t be done as accurately or quickly with freehand drawing.
What’s your favorite technique to use? Let us know in the comments.