{"id":1682,"date":"2020-06-10T09:12:47","date_gmt":"2020-06-10T01:12:47","guid":{"rendered":"http:\/\/tg.zhongwei666.com\/?page_id=1682"},"modified":"2020-08-06T11:33:30","modified_gmt":"2020-08-06T03:33:30","slug":"color-grading","status":"publish","type":"page","link":"http:\/\/www.iga-laboratory.com\/?page_id=1682","title":{"rendered":"Color Grading"},"content":{"rendered":"\n\t

\n\t\t\t\t\tiga\n\t\t\t\t<\/h3>\n\t

\n\t\t\t\t\tcolor grading\n\t\t\t\t<\/h2>\n

\n\t\tcolor grading\n\t<\/h2>\n\t\t\t\t\t\t\t\t\tRuby Color Grading Standard\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\tSapphire Color Grading Standard\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\tEmerald Color Grading Standard\t\t\t<\/a>\n\t\t\t\tRuby Color Grading Standard\n\t\t\t\t\t\t\t

1.Color system<\/p>\n

The Grading Standard adopts Munsell color system to grade ruby colors.<\/p>\n

2.Terminology<\/p>\n

2.1 Munsell color system<\/b><\/strong><\/p>\n

Munsell color system\u00a0is a color calibration system based on visual perception characteristics of colors from the perspective of psychology. At present, the color system is universally adopted to categorize and calibrate colors around the globe. The Munsell color system is an approach to describe colors through a combination of hue, value, and chroma in colorimetry (or colorimetric method).<\/p>\n

\"\"<\/p>\n

2.2 Hue<\/b><\/strong><\/p>\n

The base color of hue is a color that can form equally-spaced visual intervals, including red (R), yellow (Y), green (G), blue (B), and purple (P), which constitute the base hues of ten colors when being inserted yellow-red (YR), yellow-green (YG), blue-green (BG), purple-blue (PB), and red-purple (RP). Each of the ten base hues can be further broken down to 10 equal portions, constituting 100 hues and then evenly distributed in a 360\u00b0circle. The Standard categorizes ruby colors as red (R), purple-red (pR), and orange-red (oR) for grading.<\/p>\n

2.3 Value<\/b><\/strong><\/p>\n

Value is based on the achromatic color scale. There are an altogether of 11 value scales measured by the decimal system when ideal black with zero reflectivity is set as 0 and ideal white with 100% reflectivity as 10 and the middle and the middle is divided in equidistance. The value of the color of each hue\u2019s highest chroma varies depending on hue.<\/p>\n

2.4 Chroma<\/b><\/strong><\/p>\n

Chroma represents tone\u2019s chroma. Its values go from the middle (0) and outward, increasing with the chroma of tones without an upper limit in a theoretical sense (the actual upper limit of ordinary colors is about 10 meters while that of reflective and florescent materials can reach as high as 30). As human eyes have different sensitivity to various colors, chroma does not necessarily match with each combination of tone and value.<\/p>\n

3.Standard materials<\/p>\n

The Grading Standard adopts the Munsell Book of Color-Glossy Collection for grading.<\/p>\n

4.Color grading<\/p>\n

Based on ruby\u2019s hue, value, and chroma, its colors are divided into five grades, i.e. Red, Intense Red, Vivid Red, Pigeon\u2019s Blood, and Deep Red, among which Pigeon\u2019s Blood is a special grading in-between Vivid Red and Deep Red. Please refer to Table 1 below:<\/p>\n

Table 1. Characteristics of different value & chroma grades of ruby by naked eyes<\/p>\n\n\n\n\n\n\n\n\n
Value & chroma grade<\/td>\nCharacteristics observed by naked eyes<\/td>\n<\/tr>\n
Red<\/td>\nRed<\/td>\nAppears red in reflective light, medium color<\/td>\n<\/tr>\n
Intense Red<\/td>\nIntense Red<\/td>\nAppears relatively intense red in reflective light<\/td>\n<\/tr>\n
Vivid Red<\/td>\nVivid Red<\/td>\nAppears vivid red in reflective light<\/td>\n<\/tr>\n
Pigeon\u2019s Blood<\/td>\nPigeon\u2019s Blood<\/td>\nAppears vivid and bright red like pigeon\u2019s eyes in reflective light<\/td>\n<\/tr>\n
Deep Red<\/td>\nDeep Red<\/td>\nAppears deep red in reflective light, relatively dark color<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

5.Grading environment<\/p>\n

5.1 Grading light source<\/b><\/strong><\/p>\n

A light source with a 4500K-5500K color temperature and no less than 90 in CRI should be\u00a0adopted.<\/p>\n

5.2 Grading environment<\/b><\/strong><\/p>\n

Color grading should be conducted in an indoor environment without direct sunlight. The tone of grading environment should be white or grey and a white background should be used under the grading light source.<\/p>\n

6.Grading method<\/p>\n

6.1 Value and chroma grading principles<\/b><\/strong><\/p>\n

6.1.1 When the to-be-graded ruby\u2019s value and chroma are the same as a certain standard sample, then the grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded ruby\u2019s value and chroma.<\/p>\n

6.1.2 Whne the to-be-graded ruby\u2019s value and chroma are in-between two successive standard samples, then the lower grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded ruby\u2019s value and chroma.<\/p>\n

6.1.3 When the to-be-graded ruby\u2019s value and chroma are higher than the highest grade of the standard sample, then the highest grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded ruby\u2019s value and chroma.<\/p>\n

6.1.4 When the to-be-graded ruby\u2019s value and chroma are lower than the lowest grade of the standard sample, then the lowest grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded ruby\u2019s value and chroma.<\/p>\n

6.2 Observation method<\/b><\/strong><\/p>\n

In the defined observation environment, gems are placed about 25cm away from the light source, the same parts of which as the standard sample are observed from the direction of worktable and compared with the Munsell Book of Color-Glossy Collection, and graded according to the color of gems against reflection color. Gems can be tilted\u00a0by an angle of about 30o<\/sup>.<\/p>\n\t\t\t\tSapphire Color Grading Standard\n\t\t\t\t\t\t\t

1.Color system<\/p>\n

The Grading Standard adopts Munsell color system to grade sapphire colors.<\/p>\n

2.Terminology<\/p>\n

2.1 Munsell color system<\/b><\/strong><\/p>\n

Munsell color system\u00a0is a color calibration system based on visual perception characteristics of colors from the perspective of psychology. At present, the color system is universally adopted to categorize and calibrate colors around the globe. The Munsell color system is an approach to describe colors through a combination of hue, value, and chroma in colorimetry (or colorimetric method).<\/p>\n

\"\"<\/p>\n

2.2 Hue<\/b><\/strong><\/p>\n

The base color of hue is a color that can form equally-spaced visual intervals, including red (R), yellow (Y), green (G), blue (B), and purple (P), which constitute the base hues of ten colors when being inserted yellow-red (YR), yellow-green (YG), blue-green (BG), purple-blue (PB), and red-purple (RP). Each of the ten base hues can be further broken down to 10 equal portions, constituting 100 hues and then evenly distributed in a 360\u00b0circle. The Standard categorizes ruby colors as red (R), purple-red (pR), and orange-red (oR) for grading.<\/p>\n

2.3 Value<\/b><\/strong><\/p>\n

Value is based on the achromatic color scale. There are an altogether of 11 value scales measured by the decimal system when ideal black with zero reflectivity is set as 0 and ideal white with 100% reflectivity as 10 and the middle and the middle is divided in equidistance. The value of the color of each hue\u2019s highest chroma varies depending on hue.<\/p>\n

2.4 Chroma<\/b><\/strong><\/p>\n

Chroma represents tone\u2019s chroma. Its values go from the middle (0) and outward, increasing with the chroma of tones without an upper limit in a theoretical sense (the actual upper limit of ordinary colors is about 10 meters while that of reflective and florescent materials can reach as high as 30). As human eyes have different sensitivity to various colors, chroma does not necessarily match with each combination of tone and value.<\/p>\n

3.Standard materials<\/p>\n

The Grading Standard adopts the Munsell Book of Color-Glossy Collection for grading.<\/p>\n

4.Color grading<\/p>\n

Based on sapphire\u2019s hue, value, and chroma, its colors are divided into seven grades, i.e. Light Blue, Blue, Intense Blue, Vivid Blue, Royal Blue, Cornflower Blue, and Deep Blue, among which Royal Blue is a special grading in-between Vivid Blue and Deep Blue and Cornflower Blue is a special grading in-between Intense Blue and Vivid Blue. Please refer to Table 1 below:<\/p>\n

Table 1.Characteristics of different value & chroma grades of emerald by naked eyes<\/p>\n\n\n\n\n\n\n\n\n\n\n
Value & chroma grade<\/td>\nCharacteristics observed by naked eyes<\/td>\n<\/tr>\n
Light Blue<\/td>\nLight Blue<\/td>\nAppears light blue in reflective light, light color<\/td>\n<\/tr>\n
Blue<\/td>\nBlue<\/td>\nAppears blue in reflective light, medium color<\/td>\n<\/tr>\n
Intense Blue<\/td>\nIntense Blue<\/td>\nAppears relatively intense blue in reflective light<\/td>\n<\/tr>\n
Vivid Blue<\/td>\nVivid Blue<\/td>\nAppears vivid blue in reflective light<\/td>\n<\/tr>\n
Royal Blue<\/td>\nRoyal Blue<\/td>\nAppears vivid and bright blue in reflective light<\/td>\n<\/tr>\n
Cornflower Blue<\/td>\nCornflower Blue<\/td>\nAppears relatively rich blue to vivid blue with a velvety and dreamy gloss<\/td>\n<\/tr>\n
Deep Blue<\/td>\nDeep Blue<\/td>\nAppears deep blue in reflective light, relatively dark color<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n5.Grading environment
\n<\/b><\/strong>\n

5.1 Grading light source<\/b><\/strong><\/p>\n

A light source with a 4500K-5500K color temperature and no less than 90 in CRI should be\u00a0adopted.<\/p>\n

5.2 Grading environment<\/b><\/strong><\/p>\n

Color grading should be conducted in an indoor environment without direct sunlight. The tone of grading environment should be white or grey and a white background should be used under the grading light source.<\/p>\n

6.Grading method<\/p>\n

6.1 Value and chroma grading principles<\/b><\/strong><\/p>\n

6.1.1When the to-be-graded sapphire’s value and chroma are the same as a certain standard sample, then the grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded sapphire’s value and chroma.<\/p>\n

6.1.2When the to-be-graded sapphire’s value and chroma are in-between two successive standard samples, then the lower grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded sapphire’s value and chroma.<\/p>\n

6.1.3When the to-be-graded sapphire’s value and chroma are higher than the highest grade of the standard sample, then the highest grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded sapphire’s value and chroma.<\/p>\n

6.1.4When the to-be-graded sapphire’s value and chroma are lower than the lowest grade of the standard sample, then the lowest grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded sapphire’s value and chroma.<\/p>\n

6.2 Observation method<\/b><\/strong><\/p>\n

In the defined observation environment, gems are placed about 25cm away from the light source, the same parts of which as the standard sample are observed from the direction of worktable and compared with the Munsell Book of Color-Glossy Collection, and graded according to the color of gems against reflection color. Gems can be tilted\u00a0by an angle of about 30o<\/sup>.<\/p>\n\t\t\t\tEmerald Color Grading Standard\n\t\t\t\t\t\t\t

1.Color system<\/p>\n

The Grading Standard adopts Munsell color system to grade emerald colors.<\/p>\n

2.Terminology<\/p>\n

2.1 Munsell color system<\/b><\/strong><\/p>\n

Munsell color system\u00a0is a color calibration system based on visual perception characteristics of colors from the perspective of psychology. At present, the color system is universally adopted to categorize and calibrate colors around the globe. The Munsell color system is an approach to describe colors through a combination of hue, value, and chroma in colorimetry (or colorimetric method).<\/p>\n

\"\"<\/p>\n

2.2 Hue<\/b><\/strong><\/p>\n

The base color of hue is a color that can form equally-spaced visual intervals, including red (R), yellow (Y), green (G), blue (B), and purple (P), which constitute the base hues of ten colors when being inserted yellow-red (YR), yellow-green (YG), blue-green (BG), purple-blue (PB), and red-purple (RP). Each of the ten base hues can be further broken down to 10 equal portions, constituting 100 hues and then evenly distributed in a 360\u00b0circle. The Standard categorizes ruby colors as red (R), purple-red (pR), and orange-red (oR) for grading.<\/p>\n

2.3 Value<\/b><\/strong><\/p>\n

Value is based on the achromatic color scale. There are an altogether of 11 value scales measured by the decimal system when ideal black with zero reflectivity is set as 0 and ideal white with 100% reflectivity as 10 and the middle and the middle is divided in equidistance. The value of the color of each hue\u2019s highest chroma varies depending on hue.<\/p>\n

2.4 Chroma<\/b><\/strong><\/p>\n

Chroma represents tone\u2019s chroma. Its values go from the middle (0) and outward, increasing with the chroma of tones without an upper limit in a theoretical sense (the actual upper limit of ordinary colors is about 10 meters while that of reflective and florescent materials can reach as high as 30). As human eyes have different sensitivity to various colors, chroma does not necessarily match with each combination of tone and value.<\/p>\n

3.Standard materials<\/p>\n

The Grading Standard adopts the Munsell Book of Color-Glossy Collection for grading.<\/p>\n

4.Color grading<\/p>\n

Based on emerald\u2019s hue, value, and chroma, its colors are divided into six grades, i.e. Light Green, Green, Intense Green, Vivid Green, Muzo Green, and Deep Green, among which Muzo Green is a part of Vivid Green. Please refer to Table 1 below:<\/p>\n

Table 1. Characteristics of different value & chroma grades of emerald by naked eye<\/p>\n\n\n\n\n\n\n\n\n\n
Value & chroma grade<\/td>\nCharacteristics observed by naked eye<\/td>\n<\/tr>\n
Light Green<\/td>\nLight Green<\/td>\nAppears light green in reflective light, light color<\/td>\n<\/tr>\n
Green<\/td>\nGreen<\/td>\nAppears green in reflective light, medium color<\/td>\n<\/tr>\n
Intense Green<\/td>\nIntense Green<\/td>\nAppears relatively intense green in reflective light<\/td>\n<\/tr>\n
Vivid Green<\/td>\nVivid Green<\/td>\nAppears vivid green in reflective light<\/td>\n<\/tr>\n
Muzo Green<\/td>\nMuzo Green<\/td>\nAppears vivid and bright green in reflective light<\/td>\n<\/tr>\n
Deep Green<\/td>\nDeep Green<\/td>\nAppears deep green in reflective light, relatively dark color<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

5.Grading environment<\/p>\n

5.1 Grading light source<\/b><\/strong><\/p>\n

A light source with a 4500K-5500K color temperature and no less than 90 in CRI should be\u00a0adopted.<\/p>\n

5.2 Grading environment<\/b><\/strong><\/p>\n

Color grading should be conducted in an indoor environment without direct sunlight. The tone of grading environment should be white or grey and a white background should be used under the grading light source.<\/p>\n

6.Grading method<\/p>\n

6.1 Value and chroma grading principles<\/b><\/strong><\/p>\n

6.1.1When the to-be-graded emerald’s value and chroma are the same as a certain standard sample, then the grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded emerald’s value and chroma.<\/p>\n

6.1.2When the to-be-graded emerald’s value and chroma are in-between two successive standard samples, then the lower grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded emerald’s value and chroma.<\/p>\n

6.1.3When the to-be-graded emerald’s value and chroma are higher than the highest grade of the standard sample, then the highest grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded emerald’s value and chroma.<\/p>\n

6.1.4When the to-be-graded emerald’s value and chroma are lower than the lowest grade of the standard sample, then the lowest grade of the standard sample\u2019s value and chroma should be the grade of the to-be-graded emerald’s value and chroma.<\/p>\n

6.2 Observation method<\/b><\/strong><\/p>\n

In the defined observation environment, gems are placed about 25cm away from the light source, the same parts of which as the standard sample are observed from the direction of worktable and compared with the Munsell Book of Color-Glossy Collection, and graded according to the color of gems against reflection color. Gems can be tilted\u00a0by an angle of about 30o<\/sup>.<\/p>\n","protected":false},"excerpt":{"rendered":"

iga color grading color grading Ruby Color Grading Stan …<\/p>\n

Color Grading<\/span> \u67e5\u770b\u5168\u6587 »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"no-sidebar","site-content-layout":"page-builder","ast-global-header-display":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":""},"_links":{"self":[{"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=\/wp\/v2\/pages\/1682"}],"collection":[{"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1682"}],"version-history":[{"count":7,"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=\/wp\/v2\/pages\/1682\/revisions"}],"predecessor-version":[{"id":2316,"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=\/wp\/v2\/pages\/1682\/revisions\/2316"}],"wp:attachment":[{"href":"http:\/\/www.iga-laboratory.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1682"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}