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Jiangen PAN, Haiping SHEN, Yuqin Zong, Yoshi Ohno


The mismatch of spectral responsivity to the CIE V(lambda) function, i. e., the f1' index, is the most critical characteristic of photometers and tristimulus colorimeters. The f1' value varies with measurement conditions, which is often omitted in the f1' evaluation. We investigated the variations of the f1' value with different measurement conditions such as angle of incidence, spatial uniformity, and ambient temperature, by measuring eight high-grade commercial photometer heads from four manufacturers. The f1' values measured by three different facilities as well as manufacturers' data were compared. The results indicate that f1' value can change considerably under different measurement conditions depending on the design of photometers.
Proceedings Title
The CIE Expert Symposium 2008 on Advances in Photometry and Colorimetry, Turin, Italy
CIE x033:2008
Conference Dates
July 7-11, 2008
Conference Location
Turin, 1, IT


f1’ index, measurement condition, photometer heads, photometry, spectral responsivity.


PAN, J. , SHEN, H. , Zong, Y. and Ohno, Y. (2008), f1’ EVALUATION AND MEASUREMENT COMPARISON, The CIE Expert Symposium 2008 on Advances in Photometry and Colorimetry, Turin, Italy, Turin, 1, IT, [online], (Accessed June 25, 2024)


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Created September 30, 2008, Updated October 12, 2021