Harby E. Ahmed

Effect of Museum Conditions on Historical Dyed Silk Fabric with Madder Dye

Historical textiles suffer from deterioration as a result of exposure to uncontrolled environmental conditions in museums. To establish standard conditions for display of undyed and dyed silk fabrics in Egyptian museums, different artificial aging procedures (thermal, light and chemical) were applied to examine their effects on the physical, mechanical and chemical structure of the silk fiber. Samples of undyed silk and silk dyed with madder with different mordants, iron II sulphate; iron III chloride and copper sulphate were used for this purpose. These aged samples were examined for their surface morphology, color parameters (CIE Lab), mechanical properties, degree of crystallinity, secondary structure analysis and amino acids content.

From Ptolemaic to modern inked linen via Laser Induced Breakdown Spectroscopy (LIBS)

Laser Induced Breakdown Spectroscopy (LIBS) has been applied to inked linen textile that belongs to a mummys linen wrapping dated back to the Ptolemaic period (330 BC: 30 AD). The rarity of the ancient archeological piece introduced in this study has suggested the use of a model sample of currently manufactured linen for comparison purposes and optimization of the experimental conditions. The Nd:YAG laser operating at both wavelengths 532 and 1064 nm as our excitation source along with an Echelle spectrometer with an intensified charge-coupled device detector has been employed. Under the experimental conditions adopted throughout this work, the use of the visible 532 nm laser produced poorer S/B when compared to that produced by a 1064 nm laser which suggests the production of colder plasma leading to less atomization of the ablated material. Additionally, the 532 nm wavelength shows a negative behavior in ablating ink writings which was visually clear. Although, LIBS qualitative results are so comparable to that of SEM-EDX, some elements were detected only by LIBS which could be attributed to the irregularity of ink on linen. Thus, the capabilities of LIBS should be extensively exploited to the in situ measurements and analysis of archeological ink and fabrics.

Novel synthesis of nanoparticles-based back coating flame-retardant materials for historic textile fabrics conservation

Novel flame-retardant back coating layer for historic textile fabrics was developed. Silica nanoparticles originated from agriculture waste rice husk were prepared through one pot thermal method. The morphological and structure properties of nanoparticles were studied. The silica nanoparticles were further impregnated with organic borate producing flame-retardant composite. The obtained composite incorporated with the binder by mechanical mixing providing flame-retardant coating paste. The coating paste spread on the back surface of textile fabrics. Varied compositions of nanoparticles, binder and organic borate were studied in the back coating layer. The flammability, thermal stability and mechanical properties of the blank and treated samples of linen fabrics as an inner support to the historical textiles were investigated. Flame retardancy of the back-coated linen samples has improved achieved high class of flame-retardant textile fabrics of zero rate of burning compared to 80.3 mm/min for blank. The synergistic effect of flame retardancy between nanoparticles and organic borate was investigated. The tensile strength of the flame retardant fabrics was enhanced by 27% and elongation was improved. The effect of industrial aging on the flame retardancy and mechanical properties of flame-retardant back coating textiles was studied.

Surface and stratigraphic elemental analysis of an ancient Egyptian cartonnage using Laser-Induced Breakdown Spectroscopy (LIBS)

An archeological Egyptian cartonnage dating back to the Greco-Roman period around the third century BC was elementally analyzed via the sample-friendly technique, Laser-Induced Breakdown Spectroscopy (LIBS). The unique characteristics of LIBS as being a simple and fast technique, has been exploited to obtain surface elemental distribution and depth profiles for the investigated sample. An Nd:YAG laser operating at the fundamental wavelength of 1064 nm has been used as the excitation source along with an echelle spectrometer coupled to an ICCD detector for spectral dispersion and detection. Under the experimental conditions, four distinct regions were studied as ten elements were analyzed for spatial distribution along the surface and also for their depth profiles. Rapid and comprehensive visualization of the investigated regions are provided. The most relevant elements i.e. carbon, calcium, silicon, oxygen and iron suggest that the cartonnage was manufactured via the traditional method, mainly dependent on natural pigments such as metal oxides and calcium carbonate (calcite) which is consistent with the previous results of other conventional techniques used in the field of Archaeology. Supporting studies obtained by both scanning electron microscopy with energy dispersive X-ray micro-analysis (SEM-EDX) and X-ray diffraction (XRD) have been presented for comparison purposes.

Studying Irradiation Homogeneity in Light Aging for Historical Textile Conservation

Instrumental light aging is one of the most important tools for restoration and conservation of historical textiles. It used in testing stability of conservation materials, in addition to its lightening effect during the presentation in the museums. Light fading is an important tool for preparing the aged textile and other polymeric samples especially for archaeological conservation applications. Many fadometers do not give homogeneous exposure for all sample’s areas. This work studies the color changes of silk fabric dyed with turmeric (Curcuma longa L.) mordanted with alum or ferric sulfate. Color change was studied for the exposure periods ranged from five to hundred hours. Three positions of different irradiance levels were measured on the same sample namely (bottom, middle and upper). Individual color change for each position was recorded and studied. The results showed that there is non-homogeneous irradiance distribution due to different positions in fadometer or mordant used.