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PubMed1997

Color from motion: separate contributions of chromaticity and luminance.

'Color from motion' describes the perception of a spread of subjective color over achromatic regions seen as moving. The effect is produced with a stimulus display consisting of colored dots, randomly placed upon a white field, with dots in the test region differing in both chromaticity and luminance from those in the surround. Evidence is presented suggesting that color from motion may be regulated by mechanisms different from those for contour formation and color contrast. (1) Results based on ratings show that, in the absence of luminance differences between the dots in the test and those in the surround regions, chromaticity differences alone are sufficient to produce color spread from motion. As the equiluminance point is approached, subjective color spread is seen despite a reduction in the strength of the subjective contour. Thus, contour formation is not likely to be a prerequisite for color from motion. (2) Color matches show that the hue and saturation of the subjective color spread are determined largely by the chromaticity and the luminance of the dots in the test region, not by those of the dots in the surround for the values explored. This suggests that color from motion may arise in sites distinct from those responsible for the regulation of color contrast.

Color↗

PubMed2006

Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans.

This study investigated whether 12 participants with color-vision deficiency had superior visual discrimination of color-camouflaged stimuli shown on a computer screen compared with 12 participants with normal trichromatic vision. Participants were asked to distinguish a circular pattern from other patterns in which textural elements differed from the background in orientation and thickness. In one condition, stimuli were single-colored, green or red; in the other condition, stimuli were color camouflaged with a green and red mosaic overlaid onto the pattern. Color-vision deficient participants selected the correct stimuli in the color-camouflaged condition as quickly as they did in the single-colored condition. However, normal color-vision participants took longer to select the correct choice in the color-camouflaged condition than in the single-colored condition. These results suggest that participants with color-vision deficiency may have a superior visual ability to discriminate the color-camouflaged stimuli.

Adult↗

PubMed2002

Color vision in 42 Congolese patients with tuberculosis receiving ethambutol treatment.

PURPOSE: To study color vision in Congolese patients with tuberculosis receiving ethambutol therapy. METHODS: A prospective, descriptive study of color vision test in patients with systemic tuberculosis receiving ethambutol was performed between April 1995 and January 1998 at the Department of Ophthalmology, University of Kinshasa. Color vision tests were assessed with pseudoisochromatic plates (the Ishihara Pseudo-isochromatic Plates), the AO-HRR (American Optical Handy Rand Rittler), the Bölle and Kastel anomaloscope, Farnsworth-Munsell test (the D-15 and the FM-100). RESULTS: There were 42 patients with a mean age of 33 years (range, 14 to 75 years). The color vision of all the patients was found to be normal as measured by the Ishihara pseudoisochromatic plates. One (2%) patient showed color vision defect (anarchic axis] with the OA-HRR test. Three (7%) of 42 patients displayed blue-yellow color axis or anarchic axis color vision test on the D-15 test. Fifteen (36%) of 42 patients had high total error scores at the Farnsworth-Munsell 100 test. The color axis was as follows: anarchic axis (13.1%), red-green-color and blue-yellow-color combined axis (13.1%), blue-yellow color axis (7.5%). Results of the Bölle and Kastel anomaloscope were normal in all patients. CONCLUSION: Our results confirm the importance of color vision examinations in the detection of the complications of ethambutol treatment.

Adolescent↗

PubMed1998

Effects of color on perceptual and conceptual tests of implicit memory.

Two experiments are reported that explore why recent investigations of implicit memory failed to find any effects of color information on test performance. In the first experiment, participants studied colored pictures as well as words printed in colored ink without any memory instructions. During the test phase, a verbal and a pictorial version of a color-choice task (a conceptual priming test) were compared to two perceptual tests (word-stem completion and picture-fragment identification). Similar and significant amounts of priming to color occurred in both color-choice tasks. The perceptual tests were found to be sensitive to changes in the stimulus-presentation mode from study to test, but stimuli remaining the same color and those changed to black-and-white did not differ in the priming scores. In the second experiment, a mild division of attention was introduced in the study phase. Once again, priming to color was observed only in the verbal version of a color-choice test and not in the word-stem completion test. Dividing attention did not decrease performance on both implicit tests, whereas an explicit test of color recall for studied pictures suffered from dividing attention at encoding. It is concluded that a perceptual attribute such as color may be represented and coded by conceptual processing. Furthermore, automatic (or not attention-demanding) encoding processes may suffice for later conceptual tests of implicit memory. Previous failures to find any effects of color information on implicit performance are attributed to the use of perceptual priming tests.

Color Perception↗

PubMed2006

Usefulness of electronic radial endoscopic color Doppler ultrasonography in esophageal varices: comparison with convex type.

BACKGROUND: Endoscopic color Doppler ultrasonography (ECDUS) is a method for detecting color flow images in blood vessels. We previously reported on the usefulness of ECDUS (convex-type scanning instruments with forward--oblique viewing) for evaluating the hemodynamics of esophageal varices. In the present study, we report the usefulness of new electronic radial ECDUS in cases of esophageal varices by comparison with convex-type ECDUS. METHODS: Twenty-six patients with esophageal varices were identified and studied. The underlying pathologies of portal hypertension included liver cirrhosis (15 patients) and cirrhosis associated with hepatocellular carcinoma (11 patients). Endoscopic findings of esophageal varices were as follows: Cb, F3, and Ls varices in four patients; Cb, F2, and Lm varices in 21 patients; and Cb, Lm, and F1 varices in one patient. RC1 was observed in the esophagus in 14 of the 26 patients. RC2 was noted in 11 cases, and RC0 was seen in one patient. ECDUS was performed using a Pentax EG-3630UR (forward view) with a distal tip diameter of 12 mm. The instrument (electronic radial array) has a curved array scanning transducer with variable frequency (5.0, 7.5, 10.0 MHz). A Hitachi EUB 6500,8500 was used for the display, providing 270 degrees images. We monitored the color flow images of esophageal varices, paraesophageal veins, palisade veins, perforating veins, and pulsatile waves using this technique. As a control, 110 patients were examined by convex-type ECDUS. RESULTS: (1) Color flow images of esophageal varices and paraesophageal veins were obtained in 26 of the 26 patients, whereas color flow images of perforating veins were obtained in 18 of the 26 patients (69.2%). Color flow images of palisade veins were obtained in 12 of the 26 patients (46.2%). (2) Color flow images of pulsatile waves were obtained in 10 of the 26 patients (38.5%). Color flow images of pulsatile waves were detected in zero (0%) of the 4 F3 varices, in nine (42.9%) of the 21 F2 varices, and in the 1 (100%) case of F1 varices. Also, color flow images of pulsatile waves were detected in seven (50.0%) of the 14 RC1 varices, in two (18.2%) of the 11 RC2 varices, and in the 1 (100%) case of RC0 varices. (3) As a control, 110 patients were examined by convex-type ECDUS. Color flow images of esophageal varices and paraesophageal veins were obtained in 110 of the 110 patients, whereas color flow images of perforating veins were obtained in 74 of 110 (67.3%) with convex-type ECDUS. The detection rate of palisade veins with electronic radial ECDUS (12 of the 26 patients, 46.2%) was significantly higher than with convex-type ECDUS (28 of the 110 patients, 25.5%) (P<0.05). The detection rate of pulsatile waves with electronic radial ECDUS (10 of the 26 cases, 38.5%) was significantly higher than with convex-type ECDUS (3 of the 110 cases, 2.7%) (P<0.0001). CONCLUSIONS: Electronic radial ECDUS provides clear color flow images of blood vessels in esophageal varices with the additional advantages of forward-view optics and extended 270 degrees views. Electronic radial ECDUS was superior to convex-type ECDUS in detecting palisade veins and pulsatile waves.

Aged↗

PubMed1988

The effects of manipulative variables on the color of ceramic metal restorations.

Certain variables were tested for their influence on the color of ceramic metal restorations. The variables included firing temperature, condensation technique, modeling liquid, and brand of porcelain. In addition, the color of different nominal shades was compared. The color was measured with a Minolta CR-121 small-area colorimeter. The small (7 mm2) measuring area enabled readings to be made on actual crown specimens rather than disks. The results were expressed in the CIELAB color system enabling comparisons to be made related to visual perception. The following conclusions can be drawn from the study. 1. The small-area colorimeter is able to detect statistically significant and perceivable color differences between shades of porcelain. The variation in color parameters associated with making replications of a restoration is significantly greater than the error associated with making repeated color measurements of the same restoration. 2. Restorations made with the different brands of porcelain studied have noticeably different colors despite having the same nominal shade. 3. Color changes caused by the choice of modeling liquid were not statistically significant in this study. If the mean color differences are truly representative, using Rainbow or Carv-eze modeling liquids with Vita VMK porcelain may produce color changes that are just barely detectable. 4. The manipulative variables of firing temperature and condensation have little influence on the color of the restorations.

Color↗

PubMed1985

On the development of color naming in young children: data and theory.

Among the semantics of different common attributes of the environment, consistent and correct color naming seems to develop paradoxically late in children, for even young infants discriminate and categorize colors well, color is a salient feature of the child's world, and children are aware of color as a separate domain, know color terms, and respond to color questions with color names. Several specific anomalies characterize early linguistic development in this domain: Errors in beginning color naming are perseverative or random, there seems to be a minimum age for correct and consistent color naming, developmental rate shows wide individual differences, and acquisition among girls is generally faster than among boys. This essay reviews data that support these observations, and evaluates three traditional explanations for them--including the perceptual salience of color for children, experience and learning in the child, and cognitive development--against a fourth new possibility. It is hypothesized that appropriate color naming may depend on the maturation and integration of specific cortical neurological structures; among several interpretations, the neurological one accounts best for diverse characteristics of early color naming.

Adult↗

PubMed2006

Green love is ugly: emotions elicited by synesthetic grapheme-color perceptions.

Synesthetes who experience grapheme-color synesthesia often report feeling uneasy when dealing with incongruently colored graphemes although no empirical data is available to confirm this phenomenon. We studied this affective reaction related to synesthetic perceptions by means of an evaluation task. We found that the perception of an incorrectly colored word affects the judgments of emotional valence. Furthermore, this effect competed with the word's emotional valence in a categorization task thus supporting the automatic nature of this synesthetically elicited affective reaction. When manipulating word valence and word color-photism congruence, we found that responses were slower (and less accurate) for inconsistent conditions than for consistent conditions. Inconsistent conditions were defined as those where semantics and color-photism congruence did not produce a similar assessment and therefore gave rise to a negative affective reaction (i.e., positive-valence words presented in a color different from the synesthete's photism or negative-valence words presented in the photism's color). We therefore observed a modulation of the congruency effect (i.e., faster reaction times to congruently colored words than incongruently colored words). Although this congruence effect has been taken as an index of the true experience of synesthesia, we observed that it can be reversed when the experimental manipulations turn an incongruently colored word into a consistent stimulus. To our knowledge, this is the first report of an affective reaction elicited by the congruency between the synesthetically induced color of a word and the color in which the word is actually presented. The underlying neural mechanisms that might be involved in this phenomenon are discussed.

Adult↗

PubMed2006

Nipple aspirate fluid color is associated with breast cancer.

BACKGROUND: Fluid can be non-invasively aspirated from the breast nipple (nipple aspirate fluid, NAF). NAF may have many colors, including clear, white, yellow, green, and red/brown. While bloody spontaneous nipple discharge has been linked with breast cancer, the association of NAF color with cancer is not established. Our hypothesis was that red/brown NAF color was associated with breast cancer. The purpose of this study was to assess (1) if red/brown NAF is associated with the presence and progression of breast cancer, (2) the influence of prior needle or surgical biopsy on NAF color, and (3) if an association between NAF color and breast cancer was found, to develop a cancer predictive model including NAF color and cytology, and clinical information. METHODS: Specimens were obtained from 848 breasts between 1999 and 2004 after subjects enrolled in an IRB approved protocol to evaluate biologic markers of breast cancer. Cytologic evaluation was performed on Papanicolaou-stained cytospin preparations of NAF. RESULTS: Red/brown NAF was associated with breast cancer when considering all samples (p<0.001) and samples from women who did not undergo recent surgery (p=0.005). Needle biopsy did not, but surgical biopsy did influence NAF color. For the 327 women with NAF collected from both breasts, there was a significant association between red/brown NAF color and the presence of breast cancer (p=0.005). Red/brown NAF was more common in breasts with ductal carcinoma in situ than atypical hyperplasia (p=0.008). The optimal model, included NAF color, cytology, and age, was 92% sensitive and 61% specific in predicting if a woman had breast cancer. CONCLUSIONS: NAF color was associated with the presence of breast cancer and the progression from precancer to cancer in a population of women who presented to a breast cancer evaluation clinic. NAF color contributed to a highly predictive breast cancer detection model. Additional studies are warranted to determine the usefulness of NAF color in the assessment of women who present for breast cancer evaluation.

Adult↗

PubMed2006

Comparison of the color of natural teeth measured by a colorimeter and Shade Vision System.

OBJECTIVES: The objectives were to measure the difference in the color and color parameters of natural teeth measured by a tristimulus colorimeter (CM, used as a reference) and Shade Vision System (SV), and to determine the influence of color parameters on the color difference between the values measured by two instruments. METHOD: Color of 12 maxillary and mandibular anterior teeth was measured by CM and SV for 47 volunteers (number of teeth=564). Color parameters such as CIE L*, a* and b* values, chroma and hue angle measured by two instruments were compared. Chroma was calculated as C*ab=(a*2 = b*2)1/2, and hue angle was calculated as h degrees =arctan(b*/a*). The influence of color parameters measured by CM on the color difference (DeltaE*(ab)) between the values measured by two instruments was analyzed with multiple regression analysis (alpha=0.01). RESULTS: Mean DeltaE*(ab) value between the values measured by two instruments was 21.7 (+/-3.7), and the mean difference in lightness (CIE L*) and chroma was 16.2 (+/-3.9) and 13.2 (+/-3.0), respectively. Difference in hue angle was high as 132.7 (+/-53.3) degrees . Except for the hue angle, all the color parameters showed significant correlations and the coefficient of determination (r(2)) was in the range of 0.089-0.478. Based on multiple regression analysis, the standardized partial correlation coefficient (beta) of the included predictors for the color difference was -0.710 for CIE L* and -0.300 for C*(ab) (p<0.01). CONCLUSION: All the color parameters showed significant but weak correlations except for hue angle. When lightness and chroma of teeth were high, color difference between the values measured by two instruments was small. Clinical accuracy of two instruments should be investigated further.

Adult↗

PubMed2004

Assessment of propagation velocity by contrast echocardiography for standardization of color Doppler propagation velocity measurements.

BACKGROUND: Color Doppler propagation velocity (Vp) (color-Vp) has not yet been standardized, although it should be able to specifically reflect the intraventricular movements of left ventricular (LV) inflow. Because contrast echocardiography can depict a specified flow, we used this modality to standardize measurements of color-Vp of LV inflow. METHODS: We performed contrast echocardiographic examinations in 100 patients (70 men, 30 women; age 53 +/- 12 years). Four types of color-Vp were measured: by the flow wave front method and by aliasing method using 3 aliasing velocity levels based on the peak velocity of early diastolic flow of transmitral flow. We also determined contrast echocardiographic Vp by M-mode imaging of LV inflow (contrast-Vp). RESULTS: Contrast-Vp and all 4 types of color-Vp could be compared in 86 patients. Contrast-Vp was significantly lower than color-Vp ( P < .01), except for color-Vp measured at the aliasing level 50% > peak velocity of early diastolic flow >/= 40% (color-Vp 40). A close relationship was observed between contrast-Vp and color-Vp 40 ( r = 0.801, P < .0001). Contrast-Vp and color-Vp 40 showed high ability to detect abnormal transmitral flow patterns according to receiver operating characteristics curves (area under curve for contrast-Vp, 0.94; for color-Vp 40, 0.90). CONCLUSIONS: Our results should be useful in standardization of color-Vp measurement to specifically reflect propagation of the fluid elements derived from LV inflow, with ability to distinguish LV filling abnormalities.

Blood Flow Velocity↗

PubMed2001

Surface color from boundaries: a new 'watercolor' illusion.

A colored line flanking a darker border will appear to assimilate its color onto the enclosed white area over distances of up to 45 deg (the Watercolor Effect). This coloration is uniform and complete within 100 ms. We found that thin (6 arcmin), winding inducing lines with different contrasts to the ground are generally more effective than thick, straight, and equiluminant lines. Blue and red lines induce the strongest effects, but watercolor spreading may also be seen with green and yellow. On a white background, color spreading is stronger than on chromatic, gray or black backgrounds. Little or no color is perceived when a narrow white zone (gap) is inserted in between the two inducing lines. However, chains of colored dots instead of continuous lines suffice to produce spreading. Edge-induced color is also observed when the two colored lines are presented dichoptically, suggesting a cortical origin. The Watercolor Effect described here may serve to enhance figure-ground segregation by imparting surface color onto the enclosed area, and to promote grouping between distant stimulus elements. As a grouping factor, watercolor coloration wins over proximity. Assimilative color spreading may arise in two steps: First, weakening of the contour by lateral inhibition between differentially activated edge cells (local diffusion); and second, unbarriered flow of color onto the enclosed area (global diffusion).

Color Perception↗

PubMed1985

Formation of associations of colored and flavored food with induced sickness in five avian species.

Domestic ducks, geese, pigeons, quail, and chickens were given colored, flavored, or colored and flavored food and then injected with lithium chloride. Each species showed learning of color and taste aversions. Flavor facilitated the formation of color aversions in ducks, geese, and pigeons but not in quail or chickens. Color interfered with the formation of flavor aversions in quail and chickens but not in the other three species. These findings indicate that all birds can probably associate both colored and flavored food with induced sickness and that colored food is more easily associated with induced sickness than is colored water. Moreover, these findings suggest that the capacity to associate colored and flavored food with induced sickness and the interaction between color and flavor in food vary between species. Birds, such as quail and chickens, that eat relatively tasteless food rely more on color than on flavor cues when forming learned food aversions. Birds that can select their food on the basis of taste, such as ducks and geese, rely more on flavor than on color when forming aversions to food. Birds, such as pigeons, that are initially raised on tasty food before switching to predominantly tasteless food show tendencies that are similar to those of ducks and geese.

Animals↗

PubMed2004

Stability and enhancement of berry juice color.

Attractive color is one of the main sensory characteristics of fruit and berry products. Unfortunately, the color of red juices is unstable and easily susceptible to degradation, leading to a dull and weak juice color. This study was designed to investigate the color stability and copigmentation of four different berry juices enhanced by phenolic acids and commercial color enhancers. Phenolic acid enrichment improved and stabilized the color of the berry juices during storage. The commercial color enhancers immediately produced an intensive color to the juices, which, however, was not very stable. The color enhancement was intensive in strawberry and raspberry juices and effective in lingonberry and cranberry juices. Sinapic acid induced the strongest color in strawberry juice. Ferulic and sinapic acids improved raspberry juice color equally. Rosmarinic acid enhanced the color of lingonberry and cranberry juices the most. The addition of the simple cinnamic acids produced novel peaks to the end of the high-performance liquid chromatography chromatogram, indicating a formation of new compounds. It can be assumed that sinapic and ferulic acids formed new intramolecular copigmentation compounds with berry anthocyanins whereas rosmarinic acid stabilized anthocyanins intermolecularly.

Beverages↗

PubMed2001

Quantitative analysis of red color sign in the endoscopic evaluation of esophageal varices.

BACKGROUND AND STUDY AIMS: Bleeding due to esophageal variceal rupture is associated with an extremely high mortality rate. Variceal bleeding is frequent in patients who have a red color sign on endoscopy. However, the red color sign is subjectively evaluated on the basis of color tone and the shape of the varices. To allow standardization and facilitate consensus, an objective method of assessing the red color sign is needed. In this study, a system was established for quantifying the red color sign during endoscopic evaluation. PATIENTS AND METHODS: Between July 1995 and February 1997, 55 untreated patients with portal hypertension and esophageal varices identified on upper gastrointestinal endoscopy were enrolled in the study. Images obtained about 5 cm oral to the esophagogastric junction during endoscopy were stored on magnetic optical disks using an endoscopic image processor. The still images were transmitted to a computer and analyzed using computer software. The RGB components (R, red; G, green; B, blue) were measured at points showing flare consistent with the red color sign. The endoscopic assessment was based on the Japanese Research Society for Portal Hypertension's general rules for recording endoscopic findings in esophagogastric varices. RESULTS: The ratio of the red color area to the variceal area increased with increasing red color grade. There were significant positive correlations between the R and G, and G and B components. This suggests that comparing the R components alone would allow assessment of the color differences in the red color area and in the varices. The R value was significantly higher in the red color area (115 +/- 20) than in the varices (57 +/- 19). An R value of 90 was found at the boundary between the two parts (P < 0.001). CONCLUSIONS: The red color area can be automatically calculated and quantified using the analysis program. Improvements in data storage methods may allow real-time evaluation during endoscopy in the future.

Aged↗

PubMed2001

Hypnotic color blindness and performance on the Stroop test.

A suggestion for hypnotic color blindness was investigated by administering a reverse Stroop color-naming task. Prior to the suggestion for color blindness, participants learned associations between color names and shapes. Following the color blindness suggestion, participants were required to name the shapes when they appeared in colors that were either congruent or incongruent with the learned associations. The 18 high hypnotizable participants who passed the suggestion were slower to name (a) shapes in which the color name was incongruent with the color in which it was printed, (b) "unseen" rather than "seen" shapes, and (c) color-incongruent shapes that were printed in the color in which they were "color-blind." These patterns are discussed in terms of potential cognitive and social mechanisms that may mediate responses to hypnotic color blindness.

Color Vision Defects↗

PubMed2005

Evaluation of photo-mutagenicity and photo-cytotoxicity of food coloring agents.

Pigments extracted from natural products are widely used for food coloration in Japan. An investigation concerning the photo-mutagenicity and photo-carcinogenicity of frequently used colorants in Japan was performed. Colorants examined were from Laccifer lacca (lac-color), Coccus cacti (cochineal-color), Carthamus tinctorius (carthamus yellow), Gardenia augusta (gardenia yellow and gardenia blue), Monascus anka and Monascus purpureus (monascus red), the skin of Vitis vinifera and Vitis labrusca (grape-skin color), Tamarindus indica (tamarind brown) and Beta vulgaris (beet red). No significant increase in bacterial mutation was found when Salmonella typhimurium TA98, TA100 and TA102 were simultaneously treated with colorants and subjected to UVA irradiation for 30 min. When colorant solutions were subjected to UVA irradiation for 4 h, irradiated solutions containing lac-color became slightly mutagenic toward S.typhimurium TA98 without metabolic activation. A decrease in cell survival resulted when WTK-1 cells were subjected to UVA irradiation for 60 min in the presence of purpurin at 1 mg/ml. Delayed cytotoxicity was also observed following 24 h incubation in fresh medium of samples that were subjected to UVA irradiation for 60 min in the presence of colorant (carthamus yellow, grape-skin color, gardenia blue, cochineal-color, monascus red or purpurin).

Carcinogens↗

PubMed1963

System of color wheels for streptomycete taxonomy.

In the sundry systems of streptomycete taxonomy, color of the sporulating aerial mycelium is frequently employed as a systematic criterion. Color series, each containing species of similar spore colors, are generally erected; however, the range of colors encompassed within a series is often not clearly delineated by the usual word description. Therefore, a system is proposed in which the color content of each series is more accurately defined by means of color tabs. Seven spore-color series are recognized (i.e., red, gray, yellow, blue, green, violet, and white), each of which is represented by a color wheel that displays the range of colors included therein. By comparing spore colors with the color wheels, unclassified isolates can readily be assigned to appropriate color groups.

Color↗