The use of LEDs in museums is becoming more and more frequent. Benefits are claimed in terms of lighting quality, conservation and maintenance. Nonetheless the impact of LED light on collections preservation is not yet completely explored. The goal of this study was to evaluate, through exposure tests, the colour degradation and fading produced by LED: several white LEDs, with different colour temperature, and a traditional halogen lamp, were used to light up light-responsive samples. The results stressed the importance of the spectral distribution with respect to effective wavelengths in causing colour degradation, and in general white LEDs resulted more suitable, in terms of fading prevention, than traditional halogen light sources

A widely accepted definition of human comfort does not exist, but several metrics have been developed to quantify how much users appreciate environments, objects or interfaces. For visual comfort one of the most widely accepted approach is “that comfort is not discomfort”, because it is easier to provide quantitative and qualitative evaluation of visual discomfort parameters rather than comfort parameters that we don’t have a definition of. This paper presents the available suggestions and the results of a European research project about the visual comfort with LED lighting

The use of commercial biocides in outdoor environments is increasingly discouraged because of their ecotoxicity, new methods being thus invoked to control patinas of biological origin on the stone cultural heritage. The effects of secondary metabolites (usnic acid, norstictic acid, parietin) produced by saxicolous lichens, natural competitors of rock dwelling microorganisms, were investigated invitro against microcolonial fungi (MCF: Coniosporium apollinis, Coniosporium perforans, Coniosporium uncinatum, Phaeococcomyces-like sp.), coccoid cyanobacteria (Chroococcus minutus) and green algae (Scenedesmus ecornis) which commonly occur on stonework. An acetone/water 10/90 vol/vol mixture was screened as suitable to solubilise the lichen metabolites and to not affect the bioassay results. Benzalkonium chloride 1% was used as positive control.All the three metabolites (approx. 10-2mM) inhibited the growth of the assayed MCF species, displaying the same effect of benzalkonium chloride. Chroococcus and Scenedesmus exhibited sensibility to the lichen metabolites when exposed to high incubation temperatures (35°C), chemicals and temperature synergically yielding percentage decreases of intact cells with red chlorophyll epifluorescence. These findings suggest lichen secondary metabolites as allelopathic agents against rock dwelling microorganisms and as potential natural sources for their control on stone materials in restoration and conservation programmes. In this perspective, the detection of a negligible chromatic alteration (δE<0.5) caused by LSM to the white Carrara marble is reported as the first step of the necessary extensive evaluation of the LSM-stone material interactions

How road surfaces reflect light in space is a physical characteristic that plays a key role in the design of road lighting installations: by European Standards the average luminance is the target quantity to assure the required safety conditions of the motorized road traffic. Lighting systems are designed (luminous flux installed per kilometre) to comply with the above requirement, starting from reference values of road surfaces reflection published in an old scientific document. These data are obsolete and not representative of current road surfaces, but they are still used to design current LED lighting systems. European Community funded a SURFACE project to provide to EU standard organization new traceable reference data, representative of current road surfaces used in EU. The paper presents the data collections and the impact on road lighting of using available old reference data versus SURFACE collected data of current road surfaces. Results highlight advantages in using bright pavements as well the need for introducing systems for flux control in road lighting installation to compensate for the discrepancies between current reference data and actual road surface data.

Cool materials with higher solar reflectance compared with conventional materials of the same color are widely used to maintain cooler urban fabrics when exposed to solar irradiation and to mitigate the Urban Heat Island (UHI). Photo-catalytic coatings are also useful to reduce air pollutants. Many studies related to these topics have been carried out during the past few years, although the lighting implication of reflective coatings have hardly been explored. To investigate these aspects, reflective coatings were applied on portions of a road and intensely analyzed in a laboratory and on the field. The applied cool coatings were found to have much higher solar and lighting reflectance than the existing road, which lead to lower surface temperatures up to 9 °C. Non-significant variations of chromaticity coordinates were measured under different lighting conditions. However, these materials showed a relevant variation of directional properties depending on the lighting and observation conditions with respect to conventional pavements. The optical behavior of these materials affects the uniformity of visions for drivers and requires ad-hoc installation of light sources. On the other hand, potential energy savings of up to 75% were calculated for the artificial lighting of a reference road.