The golden mean, section or proportion as it is referred to is a mathematical ratio of design. The development of this is attributed to the ancient Greeks of about twenty four hundred years ago. The use of this system can be found in many architectural structures. One well known example is the Parthenon. The golden mean is still being used today in architecture, and also some artist some artists prefer to use it in their works.
To find the formula for the golden mean you will: 1. First need to make a perfect square. 2. Divide the square in half. 3. Draw a line from the mid point of the divided side to an opposing corner. 4. Use that line as the radius to strike an arc that will define the longer side of the rectangle.
So now, you will find the exact ratio of the rectangle to be 1 to 1.6180339887. But, who needs all those numbers? You can simplify this, just but multiplying the short by 1.618. The result hardly ever comes out to an even number. An example of this would be 18 x 1.618 = 29.124. If you are using regular store bought stretcher bars, you will need to round off to the nearest even size. So, you would consider making the canvas either 18×28 inches or 18×30 inches.
Finding The Area of Interest
To use the golden mean to divide the canvas and define the main area of interest, you will first need to draw diagonal lines from the opposing corners. Then strike a radius from each of the short sides to intersect with the opposing diagonals. The intersect points gives us the points of the inner rectangle. You will find this rectangle slightly smaller than that of the “thirds” Take note of the blue lines depicting the thirds rectangle
I find it much easier to use the “rule of the thirds”. And because the inner rectangle is larger, it makes for a more open composition. (Not so tight)