Penerang baku

Sebuah penerang baku adalah sumber teoritis dari cahaya tampak dengan profil (persebaran daya spektrum) yang diterbitkan. Penerang baku memberikan dasar untuk membandingkan gambar atau warna yang terekam di bawah pencahayaan yang berbeda.

Penerang CIE sunting

Komisi Internasional Penerangan (biasanya disingkat CIE dalam nama Prancisnya) adalah badan yang bertanggung jawab untuk penerbitan semua penerang baku yang banyak diketahui orang. Masing-masing dari ini dikenal dengan campuran huruf dan angka.

Ada petunjuk tentang cara untuk menghasilkan sumber cahaya secara percobaan ("sumber baku") sesuai dengan yang penerang yang lebih tua. Untuk penerang yang relatif baru (seperti seri D), peneliti tersisakan untuk mengukur profil dari sumber-sumber mereka dan membandingkan mereka dengan spektrum terterbit.

Namun demikian, mereka tidak memberikan ukuran yang disebut Indeks metamerisme untuk menilai kualitas simulator siang.^[1]^[2] Indeks metamerisme menguji seberapa baik kesesuaian lima set percontoh metamerik di bawah uji dan penerang rujukan. Dalam cara yang mirip dengan indeks sesuaian warna, perbedaan rata-rata antara metamers dihitung.^[3]

Rujukam sunting

^ CIE Technical Report (1999). A Method for Assessing the Quality of Daylight Simulators for Colorimetry. 51.2-1999 (including Supplement 1-1999). Paris: Bureau central de la CIE. ISBN 92-9034-051-7. Diarsipkan dari versi asli tanggal 2008-04-16. A method is provided for evaluating the suitability of a test source as a simulator of CIE Standard Illuminants D55, D65, or D75. The Supplement, prepared in 1999, adds the CIE Illuminant D50 to the line of illuminants where the method can be applied to. For each of these standard illuminants, spectral radiance factor data are supplied for five pairs of nonfluorescent samples that are metameric matches. The colorimetric differences of the five pairs are computed for the test illuminant; the average of these differences is taken as the visible range metamerism index and is used as a measure of the quality of the test illuminant as a simulator for nonfluorescent samples. For fluorescent samples, the quality is further assessed in terms of an ultraviolet range metamerism index, defined as the average of the colorimetric differences computed with the test illuminant for three further pairs of samples, each pair consisting of a fluorescent and a nonfluorescent sample which are metameric under the standard illuminant.
^ CIE Standard (2004). Standard Method of Assessing the Spectral Quality of Daylight Simulators for Visual Appraisal and Measurement of Colour. S012/E:2004. Diarsipkan dari versi asli tanggal 2016-03-04. Diakses tanggal 2018-09-08. Prepared by TC 1-53 "A Standard Method for Assessing the Quality of Daylight Simulators". ISO Standard 23603:2005(E).
^ Lam, Yuk-Ming; Xin, John H. (August 2002). "Evaluation of the quality of different D65 simulators for visual assessment". Color Research & Application. 27 (4): 243–251. doi:10.1002/col.10061.

[1] CIE Technical Report (1999). A Method for Assessing the Quality of Daylight Simulators for Colorimetry. 51.2-1999 (including Supplement 1-1999). Paris: Bureau central de la CIE. ISBN 92-9034-051-7. Diarsipkan dari versi asli tanggal 2008-04-16. A method is provided for evaluating the suitability of a test source as a simulator of CIE Standard Illuminants D55, D65, or D75. The Supplement, prepared in 1999, adds the CIE Illuminant D50 to the line of illuminants where the method can be applied to. For each of these standard illuminants, spectral radiance factor data are supplied for five pairs of nonfluorescent samples that are metameric matches. The colorimetric differences of the five pairs are computed for the test illuminant; the average of these differences is taken as the visible range metamerism index and is used as a measure of the quality of the test illuminant as a simulator for nonfluorescent samples. For fluorescent samples, the quality is further assessed in terms of an ultraviolet range metamerism index, defined as the average of the colorimetric differences computed with the test illuminant for three further pairs of samples, each pair consisting of a fluorescent and a nonfluorescent sample which are metameric under the standard illuminant.

[2] CIE Standard (2004). Standard Method of Assessing the Spectral Quality of Daylight Simulators for Visual Appraisal and Measurement of Colour. S012/E:2004. Diarsipkan dari versi asli tanggal 2016-03-04. Diakses tanggal 2018-09-08. Prepared by TC 1-53 "A Standard Method for Assessing the Quality of Daylight Simulators". ISO Standard 23603:2005(E).

[3] Lam, Yuk-Ming; Xin, John H. (August 2002). "Evaluation of the quality of different D65 simulators for visual assessment". Color Research & Application. 27 (4): 243–251. doi:10.1002/col.10061.

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