1. Let’s do the math first. If you will be framing your finished work, determine your frame size, tile size and space between tiles. This will let you know if you need a custom frame or if you need to trim the design, add a border of blank mat around the design, and/or choose a different tile size to fit into a standard frame. In the case of this 9" x 12" design, we made our tiles 1 1/2" square (equally divisible into 9" and 12") with a “gutter” space of 1/8". That gives us a new size of 9 5/8" x 12 7/8". Use a ruler and pencil to lightly draw small tick marks along the 4 sides of the painted design to use for cutting. Do not draw connecting lines between them.
2. Protect your work table and use a thick, durable cutting surface to cut your design. Use your metal ruler to line up the tick marks, press firmly, and slowly cut from edge to edge with the craft knife. Working with a metal ruler is best because the knife can sometimes get caught in a plastic one. Move your hand positions along the ruler if necessary and do so cautiously to avoid shifting the ruler. As you complete your cuts in one direction, set the strips aside in order to avoid confusion.
3. Use your ruler and pencil to again make tick marks on the strips for cutting into the squares. When all cuts are complete, you can gently erase any pencil marks that show. Assemble your pieces in order.
4. Cut your piece of black matboard to the new size of the tiled design you will assemble. With the pencil, lightly mark the grid on the matboard of how the design pieces will be assembled. Then just follow the grid to glue the pieces in place.
5. If desired, you can paint a coat of thick clear acrylic over the tiles to protect them.