Alternative printers have been testing their materials for decades with step wedges. We were using the wedges long before any of us had any idea that there were actually densitometers that could measure the UV stain. Or could afford them!
Originally Posted by gainer
This method of testing is essential because the range of exposure scale that people get in practice with altternative processes is much greater than the range people get printing different brands of silver papers. The pH of the papers, sensitizing mix, method of coating, and type of developer combine to create a much more variable scenario than silver printers see.