Am 09.04.2015 um 20:26 schrieb Mike Pucher:
I have a set of L*a*b* measurements of color charts that I created with a i1Pro2 spectrophotometer. The Xrite software exports L*a*b* values on a scale of L*:0-100 and *a*b*: -100 to +100*.
Is that really the case? It would surprise me, because the range of a* b* is not limited, and even less likely scaled.
I've written a script for Photoshop to automate the calculation of specific metrics of captures of those charts, but there's one snag: Photoshop displays L*a*b* values on a scale of L*:0-100 and *a*b*: -128 to +127*.
This is due to the ICC specification which defines an encodable range of a* and b* of -128 to 127. Values outside that range are not encodable in an ICC context, and I guess that's why it's like that in Photoshop. Florian.