Tip: Scaling An Image Using Grids

There are two different ways to scale a reference drawing or photograph. Each is briefly described below. In the examples provided the references are scaled-up but the same principles can be applied to scale-down a reference as well.

Note: It is suggested to use a photocopy or electronic image of your reference so as not to ruin the original. In addition, there are several graphics software that can be used to quickly overlay a grid on an image.

Method 1 - Equally Spaced Squares

• Draw a grid over your reference copy with an EQUAL distribution of squares.
• Draw a grid of EXACTLY THE SAME PROPORTION on your drawing surface. This time make the squares larger or smaller than the original to make the resulting drawing larger or smaller.
• Label the rows by letter (such as, A, B, C) and the columns by number (such as, 1, 2, 3). Do this on both grids so that each square so that the associated squares can be easily identified (for example, A1, A2, A3).
• Then transfer the image square by square from the reference copy to the drawing surface. Start by marking key intersection points between the image and the grid lines (for example, mark the point where the mouthpiece of the saxophone falls on the intersection of row 9 and column 4). Then connect the points by tracing the remainder of the image within each square.
• When the overall image has been transferred to the drawing surface, carefully remove the grid lines by erasing them or covering them.

Method 2 - Proportional Expansion

This method is particularly good for scaling up to large drawings (sizes A1, A0, or larger).

• Start with the material you want to transfer the image to (see Step 1).
• Place your reference copy in the lower left-hand corner of the drawing surface and draw the edges around the image onto the drawing surface (see Step 2).
• Draw a diagonal line through the copied shape and extend the line to the opposite corner of the drawing surface (see Step 3).
• Where the extended line meets the top or right edge of the paper draw a vertical or horizontal line respectively. This will give you the correct proportions for the expanded image. Remove any waste on the top or right of your drawing surface (see Step 4).
• Next grid both the original reference copy and the larger paper by drawing diagonal lines through the other corners (see Step 5).
• Draw horizontal and vertical lines through the intersection of the diagonal lines on the reference grid and on the drawing surface (see Step 6).
• Subdivide the grid again into smaller portions, if needed (see Step 7).
• Then transfer your drawing from the reference copy to the drawing surface as described in Method 1 (see Step 8).