I know “How to Grid a Photo”. I have used the technique many times to enlarge a photo to a larger-sized canvas or paper. The finished results are usually acceptable and contain a lot of detail. The drawback is this method is tedious and chews up a lot of time. I work in watercolors and often don’t need a lot of detail in the initial sketch. For me, a quicker way to get results is to enlarge a reference photograph in a photo editor, remove the color, and filter with a “find edges” application. After I print this out, it becomes easy to trace over the found edges by taping the print to a window allowing the light to reveal the outline for tracing. A lightbox also works, but they can be expensive, and become one more piece of equipment I must store.
This method provides me with a basic sketch, saving hours of time, and allows me to add any detail or adjustment I need. This technique will work for journaling, poster making, lettering, any type of artwork that needs to be traced.