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United States Department of Agriculture

Agricultural Research Service

Title: Evaluation of flower color using a colorimeter and the Royal Horticultural Society charts

Authors
item Ayala-Silva, Tomas
item Meerow, Alan

Submitted to: Interamerican Society of Tropical Horticulture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 27, 2006
Publication Date: July 1, 2007
Citation: Ayala Silva, T., Meerow, A.W. 2007. Evaluation of flower color using a colorimeter and the Royal Horticultural Society charts. Interamerican Society of Tropical Horticulture Proceedings.

Interpretive Summary: The appearance of flowers, fresh fruits and vegetables is one of the first quality determinants made by the consumer. Regularly the appearance of the product is the most critical factor in the initial sale. The flower color of Amaryllis (Amaryllis Hippeastrum) cultivars at the U. S. National Germplasm Repository, Miami, FL was documented using a Minolta CR-400 colorimeter and the Royal Horticultural Society Color Charts (RHSCC). Amaryllis color was measured with a Minolta Chroma Meter CR-400 portable colorimeter and flower chromaticity was recorded in Commission Internationale d’Eclairage L*, a* and b* color space coordinates. In this system of color representation the values L*, a* and b* describe a uniform three-dimensional color space, where the L* value corresponds to a dark-bright scale, a* is negative for green and positive for red, whereas b* is negative for blue and positive for yellow. The colorimeter was calibrated using a standard white plate under normal light conditions. The RHSCC charts did not agreed with visual analysis shown between cultivars that were distinguishable by eye. The colorimeter, however, allowed the description of colors that were between color charts, and had the ability to compare the specific color characteristics of different cultivars of similar color. The ability to interpose colors with the colorimeter could accept a greater precision in documentation and identification of flower color.

Technical Abstract: The visual appearance of flowers, fresh fruits and vegetables is one of the first quality determinants made by the consumer. Often the appearance of the commodity is the most critical factor in the initial sale. The flower color of Amaryllis (Amaryllis Hippeastrum) cultivars at the U. S. National Germplasm Repository, Miami, FL was documented using a Minolta CR-400 colorimeter and the Royal Horticultural Society Color Charts (RHSCC). Amaryllis color was measured with a Minolta Chroma Meter CR-400 portable tristimulus colorimeter and flower chromaticity was recorded in Commission Internationale d’Eclairage L*, a* and b* color space coordinates. In this system of color representation the values L*, a* and b* describe a uniform three-dimensional color space, where the L* value corresponds to a dark-bright scale, a* is negative for green and positive for red, whereas b* is negative for blue and positive for yellow. The colorimeter was calibrated against a standard white plate (L = 97.79, a = -0.43 and b = +2.25) under normal lighting conditions. The RHSCC descriptions did not allow discrimination between cultivars that were distinguishable by eye. The colorimeter, however, allowed the description of colors that fell between color charts, and had the ability to compare the specific color attributes of different cultivars of similar color. The ability to interpolate colors with the colorimeter could tolerate a greater precision in documentation and discrimination of flower color. Keywords: germplasm, color descriptions, Hippeastrum, colorimeter.

Last Modified: 10/24/2014
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