How to Scale Up an Image

In this video, This Old House senior technical editor Mark Powers walks you through the steps involved in scaling up an image on graph paper to create a cutting template or paint stencil.

Steps for Scaling Up an Image

1. Place the image you’d like to scale beneath a sheet of ¼-inch graph paper. Trace the image onto the grid.
2. Count the number of ¼-inch squares your image occupies from top to bottom.
3. Decide on a finished height for your image. To calculate a ratio, divide that height by the number of squares. Convert your ratio from a decimal to a percentage by moving the decimal point over two spaces.
4. Find 1-inch graph paper online. Select “Print” from your Web browser’s drop-down menu. In the print dialogue box, change the number in the “Scale” box from 100 to the ratio you arrive at from Step 3. Print the graph paper.
5. Cut the borders off your graph paper and tape the pages together to form a sheet large enough to cover your scaled image.
6. Copy your image, square for square, onto the scaled graph paper.
7. Cut out your scaled image. Now you can lay it on plywood to cut out a router template or cut the pattern from acetate to make a paint stencil.

Tools