Porosity, the measure of the open spaces within a fabric structure, is a decisive factor in the performance of textiles. It influences breathability, permeability to liquids or gases, and suitability for various industries such as apparel, medical, and technical textiles. This study compares classical porosity calculation methods with non-destructive image analysis for 24 woven fabric samples that differ in density and weave pattern. Factors such as fabric density, weave pattern, illumination conditions, magnification, and the influence of the Otsu and Yen threshold algorithms were considered. The multifactor ANOVA statistical analysis shows that fabric density and weave pattern significantly influence porosity, with illumination playing an important role, while the threshold algorithm has a minor influence. A strong correlation is found between the actual fabric porosity and the results of the image analysis, except for double-sided illumination (reflective and transmissive), where the correlation is weakest. This comprehensive investigation provides valuable insights into the reliability of different porosity assessment approaches, which is essential for applications in various textile industries.

The photographer's awareness of the light in the scene is the key to good exposure, whether it is technically correct or an expression of creativity. The article deals with the role of light and its absence, shadow, in the field of photography. Sever...

In both commercial and scientific photography, achieving accurate colour reproduction is essential. This study investigates the influence of light-shaping attachments on colour rendering indices (CRIs) under various lighting conditions. Through 180 measurements of different lighting combinations, statistical analysis reveals significant interactions between light sources, modifiers, and CRI test colour samples (TCS). Snoots consistently produce superior CRIs, while interactions between light sources and other light modifiers vary, affecting CRIs differently based on spectral distributions and material properties of the modifiers. Combining light sources and modifiers from the same manufacturer is found to enhance colour accuracy. These findings offer valuable insights for photographers, highlighting the importance of understanding light properties and light-shaping attachment effects on colour rendition. By informing best practices, this research contributes to achieving high-quality photographs across commercial and scientific domains, ensuring both accurate data representation and visually appealing results.

Light sources are usually described by luminous intensity, color temperature and color rendering index, while the harshness of the light source is often overlooked. It is also referred to as the softness or light quality and can be determined by analyzing the shadows it produces. Shadow detection is often addressed in image analysis research, but the methods usually provide solutions for removing shadows. In this research, a method is proposed for isolating shadows from test images, applying thresholding for segmentation of the shadow into umbral and penumbral regions, calculating the shadow metric, and finally calculating the final numerical evaluation of the quality of the light source, i.e., the degree of its softness or harshness. The method proved to be efficient in analyzing halogen, LED and xenon light sources in conjunction with light-shaping attachments that soften the light. The method is not influenced by the intensity of the light source and focuses exclusively on the quality of the light. The method provides a single value to describe this light property and has the potential to become a standardized method for describing the quality of light sources and light-shaping attachments.

Lighting conditions are one of the most important factors for good photographic exposure. In enclosed spaces, like a photography studio, we can control the light in several ways. We can adjust the type of light source, the shape of the light source, its intensity, and in some cases the colour temperature of the emitted light. The distance of the light source from the observed photographic scene affects the amount of light that reaches the desired target, and therefore the actual lighting conditions on the photographic scene. However, the environment surrounding the photographic scene is often overlooked. The light emitted interacts not only with the objects within the photographic scene, but also with any obstacle in the path upon which a light ray falls. Light rays can be reflected, partially reflected, absorbed, or scattered from any surface in the immediate vicinity of the scene, depending on the material properties of the objects they encounter. In the case of reflection, the observed scene is additionally illuminated by the reflected light, since the reflecting surface in the near environment acts as another light source. Lightabsorbing surfaces, on the other hand, do not affect the scene in the same way, since the light is absorbed and not multiplied by the reflection. Reflections from the surrounding environment can therefore affect the intended lighting conditions of the observed scene in ways that we did not anticipate. This study focuses on the influence of the surrounding space on the lighting conditions in an observed photographic scene by comparing the lighting situations in a scene from a photographic studio with a diverse environment and from a darkroom with minimal environmental influence. Halogen, LED, and xenon light sources are tested individually, illuminating the test scene with different intensities and colour temperatures. The illumination conditions at the observed photographic scene are described using spectrophotometric methods and image analysis to numerically describe the differences in uniform illumination of the flat scene surface. The results are analysed and compared to illustrate the influence of the surrounding space. Based on the results, guidelines for a suitable test environment in photographic research are proposed.

The research focuses on the quality of colour reproduction when using different light sources, often used toilluminate scenes in a photo studio, and different types of fabrics as lighting shapers. With the latter, the lightcan be converted into softer and more diffuse light, but the properties of the fabrics used affect the colourimpression and thus the quality of the reproduced colours. This was evaluated by analysing the colour differences which were calculated from the colorimetric values of the colour patches of the X-Rite ColorCheckerPassport test chart. Test chart was photographed in a controlled environment and illuminated with differentcombinations of light sources and tested fabrics. The results confirmed that not all combinations of variablesare suitable for use if the goal of the photograph is to achieve high quality colour reproduction.