
Paper grade definitions
I was wondering what the definition is of particular paper grades (grade 0, grade 1, etc.). The reason is that I've been using tables of filtration values to paper grades for my color head (a Philips PCS150; Philips published two, one for Kodak papers and one for Ilford papers) for some time, and although these tables work well for rough approximations, they don't seem to be quite perfect for the papers I use. I use the "constant exposure time" tables, but the exposure bobs up and down a bit as I adjust the contrast using these tables. I'd therefore like to construct my own table, but to do this I need to know how paper grades are defined or measured. I've got a Stouffer step wedge. Would I make prints from this, adjusting filtration until a particular number of steps are distinguishable, and call that grade n? If so, what's the mapping of number of steps to paper grade? If this is the wrong track, could you point me to the right one? Thanks.