I googled for a quality download of the USAF 1951 reslution test chart, but only found small or jpg files. This gif chart, small enough to post here, can be replicated to assemble a large chart for comparative testing of pinhole images. Print it without resizing to prevent introducing artifacts. The finest bars will not print perfectly due to dot spread. Actual line pairs per mm can be calculated. This was not included, as it would restrict the versatility of the chart. Feel free to post or publish it elsewhere. This is the information age, and knowledge should be as free as practical.