Photometric assessment of skin colour and lightness using a tristimulus colorimeter: reliability of inter and intra-investigator observations in healthy adult volunteers

Trujillo, O.; Vanezis, Peter; Cermignani, Monica

doi:10.1016/0379-0738(96)01939-1

Cited by 47 publications

(34 citation statements)

References 20 publications

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“…Many poikilothermic animals have the ability to adjust the hue (observable colour; Trujillo et al, 1996) of their skin to the colour of their background by a combination of swift (physiological) and longer term (morphological) pigmentation changes (Bagnara and Hadley, 1973). Pigment cells, or chromatophores, can undergo changes in cell number, cell size, pigment content, pigment dispersion within the cell, cell migration and any combination of the former.…”

Section: Introductionmentioning

confidence: 99%

Background adaptation and water acidification affect pigmentation and stress physiology of tilapia, Oreochromis mossambicus

Salm

Spanings

Gresnigt

et al. 2005

General and Comparative Endocrinology

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The ability to adjust skin darkness to the background is a common phenomenon in fish. The hormone a-melanophore stimulating hormone (aMSH) enhances skin darkening. In Mozambique tilapia, Oreochromis mossambicus L., aMSH acts as a corticotropic hormone during adaptation to water with a low pH, in addition to its role in skin colouration. In the current study, we investigated the responses of this fish to these two environmental challenges when it is exposed to both simultaneously. The skin darkening of tilapia on a black background and the lightening on grey and white backgrounds is compromised in water with a low pH, indicating that the two vastly different processes both rely on aMSH -regulatory mechanisms.If the water is acidified after 25 days of undisturbed background adaptation, fish showed a transient pigmentation change but recovered after two days and continued the adaptation of their skin darkness to match the background. Black backgrounds are experienced by tilapia as more stressful than grey or white backgrounds both in neutral and in low pH water. A decrease of water pH from 7.8 to 4.5 applied over a twoday period was not experienced as stressful when combined with background adaptation, based on unchanged plasma pH and plasma aMSH and Na levels. However, when water pH was lowered after 25 days of undisturbed background adaptation, particularly aMSH levels increased chronically. In these fish, plasma pH and Na levels had decreased, indicating a reduced capacity to maintain ion-homeostasis, implicating that the fish indeed experience stress. We conclude that simultaneous exposure to these two types of stressor has a lower impact on the physiology of tilapia than subsequent exposure to the stressors. * Cover Letter

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Section: Introductionmentioning

confidence: 99%

Background adaptation and water acidification affect pigmentation and stress physiology of tilapia, Oreochromis mossambicus

Salm

Spanings

Gresnigt

et al. 2005

General and Comparative Endocrinology

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“…A colorimeter can be used to calculate the relative luminosity and hues of a surface, such as skin, thus allowing a more accurate, non-subjective assessment of color than by visual assessment [18,19]. Colorimetry has been used to evaluate skin color and postmortem hypostasis [15,[20][21][22][23]. For the purpose of this study, yellowness was measured using the calculated b* value and by using two specific measures of yellow: the American Society for Testing Materials (ASTM) E313 and D1925 values [24].…”

Section: Introductionmentioning

confidence: 99%

Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises

Hughes¹,

Langlois

2010

Forensic Sci Med Pathol

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Bruises can have medicolegal significance such that the age of a bruise may be an important issue. This study sought to determine if colorimetry or reflectance spectrophotometry could be employed to objectively estimate the age of bruises. Based on a previously described method, reflectance spectrophotometric scans were obtained from bruises using a Cary 100 Bio spectrophotometer fitted with a fibre-optic reflectance probe. Measurements were taken from the bruise and a control area. Software was used to calculate the first derivative at 490 and 480 nm; the proportion of oxygenated hemoglobin was calculated using an isobestic point method and a software application converted the scan data into colorimetry data. In addition, data on factors that might be associated with the determination of the age of a bruise: subject age, subject sex, degree of trauma, bruise size, skin color, body build, and depth of bruise were recorded. From 147 subjects, 233 reflectance spectrophotometry scans were obtained for analysis. The age of the bruises ranged from 0.5 to 231.5 h. A General Linear Model analysis method was used. This revealed that colorimetric measurement of the yellowness of a bruise accounted for 13% of the bruise age. By incorporation of the other recorded data (as above), yellowness could predict up to 32% of the age of a bruise-implying that 68% of the variation was dependent on other factors. However, critical appraisal of the model revealed that the colorimetry method of determining the age of a bruise was affected by skin tone and required a measure of the proportion of oxygenated hemoglobin, which is obtained by spectrophotometric methods. Using spectrophotometry, the first derivative at 490 nm alone accounted for 18% of the bruise age estimate. When additional factors (subject sex, bruise depth and oxygenation of hemoglobin) were included in the General Linear Model this increased to 31%-implying that 69% of the variation was dependent on other factors. This indicates that spectrophotometry would be of more use that colorimetry for assessing the age of bruises, but the spectrophotometric method used needs to be refined to provide useful data regarding the estimated age of a bruise. Such refinements might include the use of multiple readings or utilizing a comprehensive mathematical model of the optics of skin.

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“…Two different objective approaches can be employed in the colour changes estimation: the use of a colorimeter or spectrophotometer [14][15][16][17][18] or an image processor, which evaluates the object's image from a digital camera. The image analysis of the object's picture obtained by a digital camera was used for the purposes of this study.…”

Section: Introductionmentioning

confidence: 99%

“…One of such changes is the colour. In forensic medicine, colour changes were studied for different purposes [14][15][16][17][18] and for age estimation [19][20][21][22][23]. One of the causes of colour changes is the glycation of proteins, which gives advanced glycation end products (AGEs).…”

Section: Introductionmentioning

confidence: 99%

Changes in colour of different human tissues as a marker of age

2006

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This study deals with age estimation based on colour changes of human tissue from the intervertebral discs, Achilles tendon and rib cartilage. The investigated colour changes are the result of the accumulation of non-enzymatic browning products in the tissue. Samples of excised tissues were photographed with a digital camera and the pictures were evaluated using the image analysis processor Lucia G 4.11 processor. The values of the intensities of the RGB channels (MeanRed, Mean Green, MeanBlue) and parameters from the IHS system (MeanSaturation, HueTypical, HueVariation, BrightVariation and MeanBrightness) were evaluated. The results confirm that colour changes of some tissues depend on ageing and are a good tool for age estimation.

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Photometric assessment of skin colour and lightness using a tristimulus colorimeter: reliability of inter and intra-investigator observations in healthy adult volunteers

Cited by 47 publications

References 20 publications

Background adaptation and water acidification affect pigmentation and stress physiology of tilapia, Oreochromis mossambicus

Background adaptation and water acidification affect pigmentation and stress physiology of tilapia, Oreochromis mossambicus

Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises

Changes in colour of different human tissues as a marker of age

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