Superficial and Shroud-like coloration of linen by short laser pulses in the vacuum ultraviolet (original) (raw)
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Coloring linens with excimer lasers to simulate the body image of the Turin Shroud
Applied Optics 47, 1278-1283 (2008), 2008
The body image of the Turin Shroud has not yet been explained by traditional science; so a great interest in a possible mechanism of image formation still exists. We present preliminary results of excimer laser irradiation (wavelength of 308 nm) of a raw linen fabric and of a linen cloth. The permanent coloration of both linens is a threshold effect of the laser beam intensity, and it can be achieved only in a narrow range of irradiation parameters, which are strongly dependent on the pulse width and time sequence of laser shots. We also obtained the first direct evidence of latent images impressed on linen that appear in a relatively long period (one year) after laser irradiation that at first did not generate a clear image. The results are compared with the characteristics of the Turin Shroud, reflecting the possibility that a burst of directional ultraviolet radiation may have played a role in the formation of the Shroud image. © 2008 Optical Society of America
Shroud-like coloration of linen by nanosecond laser pulses
We present a survey on five-years experiments of excimer laser irradiation of linen fabrics, seeking for a coloration mechanism able to reproduce the microscopic complexity of the body image embedded onto the Shroud of Turin. We achieved a superficial Shroud-like coloration in a narrow range of irradiation parameters. We also obtained latent coloration that appears after artificial or natural aging of linen following laser irradiations that at first did not generate any visible effect. Most importantly, we have recognized distinct photo-chemical processes that account for both coloration and latent coloration. These processes may have played a role in the generation of the body image on the Shroud of Turin.
Deep Ultraviolet Radiation Simulates the Turin Shroud Image
Journal of Imaging Science and Technology 54, 040302-(6) (2010), 2010
The faint yellowed body image embedded into the linen cloth of the Turin Shroud has peculiar chemical and physical characteristics that at the moment cannot be replicated all together in laboratory. The authors present experimental results of ArF excimer laser irradiation (wavelength 193 nm) of a raw linen fabric, seeking for coloration similar to that of the Shroud image. The authors achieved a permanent yellow coloration of linen as a threshold effect of the laser beam intensity and number of shots. Most important, the authors have achieved for the first time a submicrometer depth of coloration of the outermost part of the fibers, leaving a colorless fiber medulla. The authors also obtained latent coloration that appears after artificial aging of linen following laser irradiation that at first did not generate any visible effect. The authors have recognized different physical and chemical processes involved in both coloration and latent coloration. The comparison of the Turin Shroud image with the results of our ArF laser irradiation shows an interesting overlap of the main physical and chemical features.
SHS web of conference, vol. 15, 00005 (2015) edited by B. Barberis, F. Lattarulo, P. Di Lazzaro, D. Petri., 2015
We present new experimental results on ultraviolet laser processing of linen fabrics that complete and update the previous studies at the ENEA Research Centre of Frascati seeking a coloration mechanism able to reproduce the microscopic complexity of the body images embedded onto the Shroud of Turin. The achievement of a Shroud-like coloration of linens by using vacuum ultraviolet light pulses allowed to recognize the main photochemical reactions possibly involved in the coloration process. The identification of these reactions offered hints for long-term conservation measures of the body images on the Shroud of Turin. Finally, we discuss how image processing of photographs of the Shroud may cause misleading effects, which led some researchers to perceive, e.g., inscriptions and a second face on the backside of the cloth, which are unlikely to be on the Shroud, confirming that there is a narrow boundary between image enhancement and manipulation.
SPIE Proceedings HPLS&A, 2019
The archaeological cloth known as the Shroud of Turin is a controversial object for both scientific and religious reasons. After a brief introduction on the scientific data about the age of the cloth and the microscopic complexity of the images embedded on it, we discuss the unique reddish color of blood stains on the Shroud, which caught the attention of several scholars in the last decades. Various hypotheses were proposed to explain the blood stains reddish color, and the experimental tests produced uncertain results because data were not sufficient or were obtained in vitro. We have tested the strength of two hypotheses, namely, the long term influence of ultraviolet (UV) light on high-bilirubin blood and the presence of carboxyhemoglobin, respectively by RGB color analyses of high-bilirubin blood after irradiation by ns excimer laser pulses and UV lamp and by the study of the spectral reflectance of the blood stains on the Shroud.
THE CONSERVATION OF THE SHROUD OF TURIN: OPTICAL STUDIES
Energia Ambiente Innovazione Special issue on conservation of cultural heritage, pp. 89-94, 2012
The ancient linen cloth of the Shroud of Turin is one of the most studied archaeological objects in history, mainly because of the unexplained nature of its image. We have recently irradiated linen fabrics by excimer laser pulses obtaining a Shroud-like coloration, nd have recognized photo-chemical processes that may have played a role in the formation of the image embedded into the Shroud. Our results suggest some actions aimed at a long-term conservation of the Shroud and of its image
A Physical Hypothesis on the Origin of the Body Image Embedded into the Turin Shroud
2000
The faint body image embedded into the Turin Shroud has not yet explained by science. We present experimental results of excimer laser irradiation (wavelengths 308 nm and 193 nm) of a raw linen fabric and of a linen cloth, seeking for a possible mechanism of image formation. We achieved a permanent coloration of both linens as a threshold effect of
Image formation of the Turin Shroud: Hypothesis based on water vapor effects of light absorption
Scientific Research and Essays, 2012
The Shroud of Turin displays a weak front and back body image which inter alia is very superficial and possesses three-dimensional properties. Up to now it has been impossible to reproduce all its characteristics at the same time albeit several attempts were made in many laboratories. But lately, coloration similar to that of the Shroud has been imprinted on dry linen cloths with a powerful VUV radiation of an excimer laser, which however does not exclude the fact that a different laser source could do the same. In fact, a new hypothesis is advanced here which is based on the irradiation of wet linen cloths with a short and powerful pulse of a CO 2 laser. Besides the well known features of pulsed IR laser, the hypothesis is based solely on the peculiar optical and thermal properties of water and vapor, and therein an experimental investigation is proposed to prove its validity.
Laser cleaning of ancient textiles
Applied Surface Science, 2005
In this work, we tried to answer two questions: (i) are laser pulses, prior to SEM investigation, a suitable tool to recognize fibres contained in archaeological findings? (ii) are laser pulses a suitable tool to properly clean those textiles? The anaerobic environment (i.e. the peatery), aiding the preservation of such handmade textiles, often impregnates the textiles, in such a way that the normal chemical procedures for cleaning are not sufficient; besides the removal of the material could make the sample brittle. Laser pulses may offer an alternative method of cleaning. In this experimental work (performed on cotton samples), laser radiation effects have been investigated using several combinations of the two main laser parameters namely energy density and number of pulses. Since textile findings are quite rare, modern samples undergone to an artificial ageing have been previously treated. Scanning electron microscopy (SEM) has been used to examine the fibres before and after the treatment. This paper reports on early stages of research regarding fibre response to UV laser irradiation detected with SEM. The obtained experimental results can be considered as a first step of a more detailed study aiming at dirt and consolidant removal without impinging the original textiles. #