Organic colorants based on lac dye and brazilwood as markers for a chronology and geography of medieval scriptoria: a chemometrics approach

This work presents the first proof of concept for the use of molecular fluorescence signatures in medieval colours based on lac dye and brazilwood lake pigments. These two important medieval dyes were tested as markers using their UV–Visible emission and excitation spectra. These medieval paints had been previously fully characterized through a multi-analytical approach. In this work, molecular fluorescence spectra were acquired in manuscripts dating from 12th to 15th c., which were produced in monastic scriptoria or workshops. First, the spectral distribution and relative intensity of the emission and excitation spectra were discussed in detail by comparison with reference compounds, including reproductions of paints based on medieval technical texts. It was possible to group the spectra according to recipe specificities. Then, statistical methods (principal component analysis and hierarchical cluster analysis) were applied to the same fluorescence spectra and the generated clusters were compared with the previous ones. Principal component analysis was initially employed to eliminate redundancy in fluorescence data, so minimizing bias on the hierarchical cluster analysis results. Except for some misplaced spectra, the placement of samples per group was confirmed. The outliers resulted from either a poor signal to noise ratio or occurred because certain paints were unique, such as the colour produced by mixing lac dye and brazilwood, which was found in manuscripts from the Alcobaça monastic scriptorium. Previously, by using infrared or Raman spectroscopies, only lac dye could be detected. Notably, these paints compare well with a recipe that was reproduced from the text by Jean Le Begue, in which both dyes were required.

Pengembangan Varian Batik Ikat Celup Dusun Hendrosalam Melalui Olshop Di Era Pandemi

Pemanfaatan zat pewarna alam untuk tekstil menjadi salah satu alternatif pengganti zat pewarna berbahan kimia. Adapun zat pewarna alami diperoleh dari alam yang berasal dari hewan(lac dyes) atau tumbuhan seperti akar,kayu,batang, daun serta kulit dan bunga,getah bunga (lac dye). Contoh warna alami Tegeran,Mahoni,kelengkeng,kluwih. Ada dua teknik membuat batik jumputan pertama teknik ikat dan kedua teknik jahitan.Ikat celup menghias kain dengan cara diikat atau dijumput sedikit, dengan tali atau karet, dijelujur, dilipat sampai kedap air, lalu dicelup dengan pewarna batik. Proses pembuatan batik ikat celup kainnya diikat atau dijahit dan dikerut menggunakan tali. Seperti yang dilakukan oleh Perajin Batik Assalam RYY Dusun Hendrosalam RT 02 RW 04 Gresik. Permasalahan Mitra aspek produksi , produk yang dihasilkan masih sederhana, desainnya terbatas. Solusi yang ditawarkan diberikan Pelatihan Varian batik ikat,Syaal,Jilbab,Masker,baju,tempat tisu.dll.Aspek manajemen permasalahannya cara pemasaran konvensional,serta kurang tertib administrasi. Solusi yang ditawarkan diberikan pelatihan pemasaran Via online (whatsapp,LINE, Instagram) dll, Pelatihan Administrasi keuangan menggunakan (MS Excell).Melalui pelatihan dan pendampingan diharapkan kelompok tersebut menjadi mandiri dan bisa menghasilkan karya batik ikat celup yang bagus, serta bisa dipasarkan dalam jangkauan yang lebih luas.

Structures and dyeing performances of polyethyleneimine-carbamate linked bamboo viscose fibers dyed with lac

Polyethyleneimine (PEI)-immobilization of bamboo viscose fibers using carbamate linkages (ABF-PEI) was investigated in order to improve the dyeing properties of the fiber. Results from morphological observation, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis clearly showed the successful carbamate binding of PEI at hydroxyl groups of cellulose fiber. The adsorption studies revealed that fast and efficient adsorption was achieved for ABF-PEI. Under optimum dyeing conditions, the amount of dye adsorbed on ABF-PEI at equilibrium (>100 mg/g) was much higher than that of the unmodified fiber (<10 mg/g). The adsorption behavior of lac dyeing on the PEI-modified bamboo viscose fibers could be described by the pseudo-second-order kinetics and Langmuir isotherm. The proposed mechanism mainly involved the electrostatic ion–dipole interaction between protonated amines of PEI and negative charged sites of lac dye. The color fastness results indicated good resistance of color changes for ABF-PEI, suggesting efficiency of the surface modifying method of PEI-immobilization on bamboo viscose fibers.

Chromatographic and Spectroscopic Identification and Recognition of Natural Dyes, Uncommon Dyestuff Components and Mordants Found in the 16th Century Carpet

A multi-tool analytical practice was used for characterization of 16th century carpet manufactured in Cairo. Mild extraction method with hydrofluoric acid enabled isolation of intact flavonoids and their glycosides, anthraquinones, tannins and indigoids from fibre samples. High-performance liquid chromatography coupled to spectroscopic and mass spectrometric detectors was used for identification of natural dyes present in the historical samples. Weld, young fustic and brazilwood were identified as the dye sources in yellow thread samples. Red fibres have been colored with lac dye, whereas green fibre shades were obtained with indigo and weld. Tannin-containing plant material in combination with indigo and weld were used to obtain brown hue of thread. Four uncommon and thus-far unknown dye components were also found in the historical samples. These compounds probably represent unique fingerprint of dyed threads from this region. Scanning electron microscopy with energy-dispersive X-ray detector (SEM-EDS) and Fourier transformation infrared spectroscopy (FT-IR) were used for identification and characterization of substrates and mordants present in the historical carpet. Carbon and oxygen were detected in large quantities as a part of the wool protein. The presence of aluminum, iron and calcium indicated their usage as mordants. FT-IR analysis showed bands characteristic to woolen fibres and SEM micrographs definite structure of wool.