Digital BW, The Print

Hi,

I am attempting to calibrate my printer output using a calibrated X-Rite 810 densitometer.  I am using MIS FS inks through an Epson 1160 onto PhotoRag 308 paper; I am on a Mac computer.  I realize that this question has come up in the past, but practical elements of technique were omitted.  Below you will find the reflective densitometer (visual) output vs a 21 step stepwedge.  I did measurements using both the Randall and Piezography workflows.  If you look at the numbers carefully, you will conclude as to how shockingly non-linear they are.  I would have expected, for example that the 50 % reading would have been close to 1.7/2 = .85.  The Measured value of around 0.6 is WAY off!

Has anyone else had this experience? I would not think that my paper choice would have that much effect.  Are there subtle differences in using a reflective densitometer as opposed to a spectrophotometer to do the measurements? It would seem that for grayscale work that a densitometer should be fine.  Please advise.

Thanks!

-John Chervinsky



STEPWEDGE  CONE      RANDALL
100.0     	1.71     	1.77
95.00     	1.54     	1.66
90.00	     1.40     	1.57
85.00	     1.26     	1.45
80.00	     1.15     	1.33
75.00	     1.05	     1.20
70.00     	0.96     	1.07
65.00	     0.86     	0.95
60.00     	0.78	     0.83
55.00     	0.69      0.76
50.00	     0.61     	0.66
45.00	     0.54     	0.58
40.00	     0.48	     0.48
35.00	     0.42     	0.39
30.00     	0.36	     0.32
25.00     	0.29      0.27
20.00	     0.24     	0.21
15.00	     0.19	     0.17
10.00      0.14      0.13
5.00	      0.09	     0.09
0.00	      0.05	     0.05