Maximization of FDM-3D-Objects Gonio-Appearance Effects Using PLA and ABS Filaments and Combining Several Printing Parameters: "A Case Study".

In order to consider 3D objects from suitable Fused Deposition Modelling (FDM) printers as prototypes for the automotive sector, this sample must be able to reproduce textural effects (sparkle or graininess) or metallic or gonio-appearance to reinforce the attractive appeal of these materials. This study worked with two different commercial filaments: grey metallic PLA (poly(lactic acid)) and ABS (acrylonitrile-butadiene-styrene copolymer) with diffractive pigments. For both materials, a statistical design of experiments (DoE) was carried out to find the printing parameters effect on the final 3D-objects gonio-appearance.

Validation of a gonio-hyperspectral imaging system based on light-emitting diodes for the spectral and colorimetric analysis of automotive coatings.

In this study, a novel gonio-hyperspectral imaging system based on light-emitting diodes for the analysis of automotive coatings was validated colorimetrically and spectrally from 368 to 1309 nm. A total of 30 pearlescent, 30 metallic, and 30 solid real automotive coatings were evaluated with this system, the BYK-mac and X-Rite MA98 gonio-spectrophotometers, and also with the SPECTRO 320 spectrometer for further comparison. The results showed very precise correlations, especially in the visible range.

Improving color reproduction accuracy of a mobile liquid crystal display.

The default method for color representation on displays involves sRGB as device-independent encoding color space. For improving color reproduction accuracy, we develop a device-specific display characterization model for the Apple iPad Air 2. In separate articles, we will evaluate the same method for other devices and for other display technologies.

Visual and instrumental correlation of sparkle by the magnitude estimation method.

Most real surfaces and objects show variations in appearance with viewing and illumination directions. Besides angular dependency, they also show spatial variation in color, i.e.

Measuring color differences in automotive samples with lightness flop: a test of the AUDI2000 color-difference formula.

From a set of gonioapparent automotive samples from different manufacturers we selected 28 low-chroma color pairs with relatively small color differences predominantly in lightness. These color pairs were visually assessed with a gray scale at six different viewing angles by a panel of 10 observers. Using the Standardized Residual Sum of Squares (STRESS) index, the results of our visual experiment were tested against predictions made by 12 modern color-difference formulas.

Effects of high-color-discrimination capability spectra on color-deficient vision.

Light sources with three spectral bands in specific spectral positions are known to have high-color-discrimination capability. W. A.

Analysis of the colorimetric properties of goniochromatic colors using the MacAdam limits under different light sources.

Technological innovation in all areas has led to the appearance in recent years of new metallic and pearlescent materials, yet no exhaustive studies have been conducted to assess their colorimetric capabilities. The chromatic variability of these special-effect pigments may largely be due to the three-dimensional effect of their curved shapes and orientations when they are directionally or diffusely illuminated. Our study examines goniochromatic colors using the optimal colors (MacAdam limits) associated with normal colors (photometric scale of relative spectral reflectance from 0 to 1) under certain conventional illuminants and other light sources.

Number of discernible colors for color-deficient observers estimated from the MacAdam limits.

We estimated the number of colors perceived by color normal and color-deficient observers when looking at the theoretic limits of object-color stimuli. These limits, the optimal color stimuli, were computed for a color normal observer and CIE standard illuminant D65, and the resultant colors were expressed in the CIELAB and DIN99d color spaces. The corresponding color volumes for abnormal color vision were computed using models simulating for normal trichromatic observers the appearance for dichromats and anomalous trichomats.

[Health Surveillance Guide of workers using video display terminals: evaluation from a visual health perspective].

Background: Visual health surveillance is essential in the protection of workers who use video display terminals (VDT). In Spain, the most used is the Specific Health Surveillance Guide published in 1999 by the Ministry of Health. The increase of the scientific production upon computer related occupational visual hazards and the experience in its applicability during the last decade justify the aim of this work: reviewing the quality of the guide from the point of view of visual health.