I have been using a Datacolor SpyderPrint for the last two months. I’m following Keith Schreiber’s instructions for using the SpyderPrint to read calibration targets for digital negatives. In Keith’s method, you use the Spyder in manual mode to measure Lab* values on a target, and you use the L* values to make your curves. I decided to test the accuracy of the L* values with the following experiment.
I made a series of 20 measurements of the same sample (what I actually did was to place the spyder back in its cradle and click 20 times). Here are the results:
minimum L* value = 88.05
maximum L* value = 88.67
average L* value = 88.37
standard deviation = 0.21
Given that the Spyder measures L* values to two decimal places of precision, the lack of accuracy is shocking. Has anyone else noticed this? Or is it possible that my Spyder is defective?