Color rendition vectors of 1269 spectrophotometrically characterized test samples of the Munsell palette were analyzed for common solid-state and fluorescent lamps with respect to reference illuminants. The vectors were individually normalized to the size of color discrimination shapes obtained from the known data of just perceived differences of chromaticity and luminance. Based on the analysis performed, we categorized the rendered colors into three groups-colors rendered with high fidelity, colors rendered with increased saturation, and those rendered with distorted hue-and introduced three corresponding indexes to assess the color quality of light sources. In combination with the correlated color temperature, these indexes, which represent important color quality characteristics of white light, constitute a simple 4-D metric for an advanced rating of illumination-grade lamps.

A spacecraft is a confined system that is inhabited by a changing microbial consortium, mostly originating from life-supporting devices, equipment collected in pre-flight conditions, and crewmembers. Continuous monitoring of the spacecraft’s bioburden employing culture-based and molecular methods has shown the prevalence of various taxa, with human skin-associated microorganisms making a substantial contribution to the spacecraft microbiome. Microorganisms in spacecraft can prosper not only in planktonic growth mode but can also form more resilient biofilms that pose a higher risk to crewmembers’ health and the material integrity of the spacecraft’s equipment. Moreover, bacterial biofilms in space conditions are characterized by faster formation and acquisition of resistance to chemical and physical effects than under the same conditions on Earth, making most decontamination methods unsafe. There is currently no reported method available to combat biofilm formation in space effectively and safely. However, antibacterial photodynamic inactivation based on natural photosensitizers, which is reviewed in this work, seems to be a promising method.

Light pollution critically affects fledglings of burrow-nesting seabirds, leading to massive mortality events. The successful management of this pollutant depends upon a comprehensive understanding of the factors influencing visual sensitivity and corresponding behaviours towards light. Factors shaping the development of the visual system could account for variation in seabirds' vulnerability to light pollution. We investigated how Cory's shearwater chicks respond to selected contrasting artificial light stimuli. Chicks were subjected to blue and red light treatments, and repeatedly tested throughout the nestling period. We analysed behavioural responses (number, timing and orientation of reactions) to determine how age, exposure to experimental light stimuli and spectra influenced the onset of visually guided behaviours, thus inferring drivers of vulnerability to light pollution. Repetitive exposure to light significantly increased the number of reactions, and chicks predominantly displayed light avoidance behaviour. We did not find differences in the number of reactions, timing and orientation between blue and red light treatments. The responses did not differ across different age groups. These results provide empirical evidence for the contribution of the light available in the rearing environment to seabird visual development. They support the hypothesis that differential exposure to light during the growth period influences responses to artificial light, and that the state of visual development at fledging could be a main driver of the age bias observed during seabird fallout events. It is thus important to evaluate lighting schemes in both urban and natural areas, and determine the as yet unknown consequences that may be affecting the populations.

A key factor for safe and comfortable driving on roads are properly reflective and well visible pavement surfaces at night. The brightness of the road pavement surface depends on the amount of light falling on it and the reflection properties of the road pavement surface at any point. The luminance of the pavement depends on its physical condition, age and type of pavement, direction of illumination, and observation conditions. Different pavements can have different reflection characteristics that depend on the surface texture, materials, and binder (type and quantity). Experimental research was carried out on the carriageways and bicycle paths of Vilnius city streets, which differ in color and age. The analysis of the research results showed differences between the surface reflectance characteristics of these pavements depending on the color of the pavement, surface conditions, and age. The reflection properties of red asphalt pavements are better than black ones when the pavement surface is wet or moist. The reduced luminance coefficients of the carriageway (asphalt pavement installed in 2021) are about 12% lower than those of the carriageway pavement installed 10 years ago and about 60% lower for wet and moist pavements. The results obtained from the research are significant for street designers when choosing the type of pavement and designing street lighting.

The existence of regions of correlated color temperature (CCT) and illuminance at which the illumination is considered “pleasing” (Kruithof hypothesis) has been tested in several outdoor environments using a smart tetrachromatic solid-state light engine with tunable CCT and high-fidelity color rendition. Subjects from a culturally homogeneous group were asked to find the most “pleasing” illumination conditions at the set illuminance levels of 5 lx and 50 lx by performing a CCT adjustment task within a wide range of 1850–10,000 K at a fixed initial condition of 1900 K. The selected intervals or preferred CCT were found to shift to higher values with increased illuminance almost independently of the content of the viewed scene with statistical significance, which qualitatively is in agreement with the Kruithof hypothesis. However, the intervals of CCT for pleasing illumination were found to be shifted to a broader and higher “warm white” range than those predicted by Kruithof. In addition, subjects were asked to find the most pleasing illumination conditions when the adjustment of CCT was accompanied by instantaneous dimming in order to maintain constant circadian irradiance. At low and high set circadian irradiance levels corresponding to 5 lx and 50 lx illuminance at the CCT of 1900 K, subjects preferred moderate dimming with lower CCTs and more noticeable dimming without the reduction of CCT, respectively.