Artists often need to enlarge drawings to paint a large picture or create a mural. Many people find it more difficult to work on a large scale, so they start with a small sketch and transform it into a larger piece. Keeping the same proportions while enlarging a drawing is difficult freehand, but there are tools to help you do so both manually and electronically.
A slide projector takes an image from a slide and enlarges it on a screen or wall. Take a drawing to an office supply store or print shop that makes slides or scan the image onto your computer and send the image to an online slide business. The slide will be ready in about a week. Project the image on a wall or canvas.
An overhead projector also projects a drawing on a wall or canvas. Have an office supply or print shop copy your drawing on a transparency. This method works best for simple outline drawings. The lines must be of medium thickness and in black and white. An overhead projector picture is not as detailed as that produced by a slide projector.
Use a scanner to enlarge your drawing on your computer. Some scanners have an enlargement option before the image is sent to the computer. Edit the size of the image in a photo editing program. If the size you desire is larger than your printer can handle, take the job to a professional print shop. After you print the drawing, use the image as is or trace it onto a wall or canvas.
The grid technique to enlarge drawings does not require any equipment other than a ruler. Divide the smaller drawing into small and even squares. Draw a larger grid with the same number of squares on the wall. Copy the drawing, square by square. This technique makes copying the proportion of the smaller drawing in freeform enlargement easier.
Use a copy machine to enlarge the drawing if you do not need the enlarged picture bigger than what the copy machine can produce. Scan the image into the copier and select the image size option. Pick the percentage you want to use to enlarge the drawing. Most copiers also have a color or black-and-white option. Print the drawing and trace it onto a canvas or use it as is.
A pantograph is a simple machine used to enlarge drawings or maps. It is made of several parallelograms that move together so that when you trace one line, it moves a pencil on the opposite end of the pantograph. Set the pantograph to enlarge the drawing by changing the position of the pencil and the pointer. Pantographs can also reduce pictures.