Frames mark the boxes in which check mark will be examined. Generally, it is a rectangle with external dimension within the limits of 4-10 mm. Inside the frame, there is a free area for possible check mark. The size of this area must be selected with regard to resolution with which the forms will be scanned. In the scanned document, dimensions of the inner area must be at least 25 x 25 points and thickness of the frame at least 8 points (1 mm).