Have you looked at
http://stonerosephotos.com/blog/zone-system/density/
http://stonerosephotos.com/blog/2012/01/ink-density-reflectance-and-l/comment-page-1/
I don't know the topic but that seems to allow computing reflection and
density from Y values.
Normand
Le 2020-01-11 à 21 h 16, Brown, James William a écrit :
In a previous email I was trying to use chartread but I now think spotread is
more appropriate.
I have read a 10-step target with the following values.
Result is XYZ: 88.589951 92.284256 75.495405, D50 Lab: 96.936379 -0.713697
0.538958
Result is XYZ: 76.341950 79.881033 66.063419, D50 Lab: 91.631455 -1.368469
-0.158627
Result is XYZ: 57.279109 59.837903 50.099307, D50 Lab: 81.750003 -1.016969
-0.836566
Result is XYZ: 42.619616 44.417210 37.347080, D50 Lab: 72.506483 -0.617372
-0.975367
Result is XYZ: 29.469258 30.859874 25.531908, D50 Lab: 62.389165 -1.085745
-0.133362
Result is XYZ: 20.185150 21.047218 17.720048, D50 Lab: 53.001133 -0.531669
-0.812328
Result is XYZ: 12.398663 12.970320 10.733602, D50 Lab: 42.718490 -0.726310
-0.108117
Result is XYZ: 7.139078 7.530363 6.128490, D50 Lab: 32.985021 -1.186517 0.379436
Result is XYZ: 2.711866 2.817359 2.173525, D50 Lab: 19.297074 -0.086656 1.343337
Result is XYZ: 0.291114 0.308121 0.238760, D50 Lab: 2.783247 -0.241378 0.290949
I am trying to get to reflection density. The formula I have depends on a value
of %Reflectance.
Is there a formula to get to %R from any of the values read by spotread?
Thank you,
Jim
