Quote Originally Posted by lhalcong View Post
note: I was not sure if this forum is the right place for this question but I didnt know where else to post.

Expecting to emulate the Zone System Steps using the help of Photoshop, I created a stepwedge of 11 Zones in aRGB space. The steps used were:

0 - I - II III IV V - VI VII VIII - IX - X
0 33 51 72 94 126 143 169 197 224 255


Having printed this on Matte finish Cold Press Natural Epson professional paper using an Epson R2880 Pro printer from Photoshop Managing color and the right paper profile from Epson, I went outside under very even ilumination overcast sky, I spot mettered each of the steps with a Sekonik Light meter in reflective mode. To my dissapointment, the steps do not equal into a one stop difference between one step and the other. For some steps the difference was 1/2 stop or less, particularly towards highlights area. Also there seem to be a big jump in tones from Zone 9 to Zone 10 in retrospect to traditional darkroom. I don't think there is enough room in between steps to vary the tones in such a way that would accomodate the 1 stop difference.

My idea was to shoot this with Film to study expansion and contraction all in one frame. In other words, I would shoot several frames of the same card, then develop them first Normal, then +15% time, +30% etc with the idea of arriving to my N+1, N+2 , N-1, N-2 times. I came up with this, first because I dont have a densitomer, neither do I want a super exact science, and I thought it would be good to be able to do this all in one frame.

Thank you for any ideas regarding the steps in the wedge and zone system, or on why this will not work ?
if everyone agrees that this will not work, what is a practical way to arrive at my N+1 N+2, etc times, without a densitometer.
Is there a formula to calculate the resulting print density? Is the 126 is about 0.75 density?