Clarification of differences between variable achromatic color and variable chromatic color methods in the Helmholtz–Kohlrausch effect

2007

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An important finding in the present study is that ''zero-grayness luminance'' proposed by Evans gives approximately the same perceived brightness for spectrum colors irrespective of hues. The luminance values with the same perceived brightness for spectrum colors are directly derived on the basis of VCC method proposed by the senior author. It corresponds to the spectral luminosity function V b2 (k;VCC). In the study process, we had some doubts on the luminosity function CIE V b2 (k) on the heterochromatic brightness match. In other words, CIE V b2 (k) may not be used for scientific study. The problem is discussed in Appendix briefly.

Section: Information Already Confirmed On Perceived Brightness or Ligmentioning

confidence: 84%

Section: G 0 Luminance Proposed By Evans Has Approximatelymentioning

confidence: 98%

Section: Information Already Confirmed On Perceived Brightness or Ligmentioning

confidence: 98%

See 1 more Smart Citation

A relationship between zero‐grayness luminance by Evans and perceived brightness of spectrum colors

Nayatani

2007

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“…In this case, the constancy of perceived lightness at a specified W-Bk and Chroma automatically holds approximately irrespective of hue. [16][17][18][19][20] This means that the H-K effect is already taken into account in the observations, although its theoretical prediction is very difficult with the present colorimetry. The difficulties are discussed in the next section in detail.…”

Section: By Hering)mentioning

confidence: 91%

Proposal of a new concept for color‐appearance modeling

Nayatani¹,

2007

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A new type of color-appearance model (CAM) is proposed together with its concept and flow of formulations. The topics described are: (1) The existence of two kinds of color-appearance models, CAMs previously used and CAMs newly proposed. (2) All the CAMs, previously developed and used, do not predict color-appearance attribute of perceived lightness of object colors under any illuminations. They may be adequately called ''the model for predicting color-appearance match between object colors under different adapting conditions.'' (3) Newly improved CAMs take the HelmholtzKohlrausch effect in the VCC method into account. They can determine object colors with the same Tone (equi-perceived lightness, equi-whiteness-blackness, and equi-perceived chroma) irrespective of hues under reference illuminant. The newly improved models can be named Integrated CAMs. Their applicable fields are described in detail.

“…It must be recognized that variable achromatic color (VAC) method does not specify the condition of equality on perceived brightness or perceived lightness. 11,12 A proposed ''integrated photometric system'' has the following features:…”

Section: A Proposal Of Expected Photometric Systemmentioning

confidence: 99%

A tentative proposal for integrated photometric system, and its application to luminous colors

Nayatani¹,

2007

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A new proposal tentatively called ''integrated photometric system'' is given together with a detailed explanation of its structure. The proposal gives the following procedures: step 1 can determine CIE photometric quantities, step 2 can determine their perceived-photometric correlates by applying the correction to the quantities derived in step 1. The present proposal solves the problem of coexistence of the two kinds of expected requirements in photometry suggested by Judd. In the present article, the formulas used in the step 2 are given only for luminous colors. The formulas for object colors will be given in a future article. Five applications of luminous colors are given for the step 2 of the proposed system. These applications will make it possible to promote the use of the proposed photometric system.