Color Defects Research Articles

Integrasi Six Sigma dan FMEA (Failure Mode And Effect Analysis) untuk Peningkatan Kualitas Produk Koran (Studi Kasus: PT. ABC Manufacturing – Sidoarjo, Jawa Timur – Indonesia)

<p><em>PT. ABC is a subsidiary of the JawaPos Group, founded in 1996, and is one of the companies in East Java engaged in printing and packaging. The products produced include magazines, books and newspapers. Of all the products that the company has created, one of the biggest defects is found in newspaper products, which is 4% of the average newspaper product production of 806.59 copies and produces a moderate defect of 22,743 copies in 2019</em><em>.</em><em> </em>I<em>n this research, the method applied is the Six Sigma method and Failure Mode and Effect Analysis (FMEA), by implementing and carrying out the stages in the Six Sigma method, namely DMAIC (Define, Measure, Analyze, and Control). From this research, the results obtained are that the company has several newspaper product defects of 181,943 copies consisting of several types of product defects, including damp paper, blurred colours, shaded printing, asymmetrical printing, and running printing. The company is currently at the 4.04 sigma level, so corrective actions need to be taken to achieve six sigma levels. By applying the Failure Mode and Effects Analysis (FMEA) method, it can be seen that the biggest and most frequent product defect is a blurred colour defect. So that the recommended alternative solution for repairs is to check the ink and replace the ink with standard ink or have a lower density, perform regular and systematic machine checks, and provide further guidance on newspaper printing production standards to all operators involved </em><em>w</em><em>ork</em><em>.</em></p>

Quantum Defects: What Pairs with the Aryl Group When Bonding to the sp2 Carbon Lattice of Single-Wall Carbon Nanotubes?

Aryl diazonium reactions are widely used to covalently modify graphitic electrodes and low-dimensional carbon materials, including the recent creation of organic color centers (OCCs) on single-wall carbon nanotube semiconductors. However, due to the experimental difficulties in resolving small functional groups over extensive carbon lattices, a basic question until now remains unanswered: what group, if any, is pairing with the aryl sp3 defect when breaking a C═C bond on the sp2 carbon lattice? Here, we show that water plays an unexpected role in completing the diazonium reaction with carbon nanotubes involving chlorosulfonic acid, acting as a nucleophilic agent that contributes -OH as the pairing group. By simply replacing water with other nucleophilic solvents, we find it is possible to create OCCs that feature an entirely new series of pairing groups, including -OCH3, -OC2H5, -OC3H7, -i-OC3H7, and -NH2, which allows us to systematically tailor the defect pairs and the optical properties of the resulting color centers. Enabled by these pairing groups, we further achieved the synthesis of OCCs with sterically bulky pairs that exhibit high purity defect photoluminescence effectively covering both the second near-infrared window and the telecom wavelengths. Our studies further suggest that these diazonium reactions proceed through the formation of carbocations in chlorosulfonic acid, rather than a radical mechanism that typically occurs in aqueous solutions. These findings uncover the unknown half of the sp3 defect pairs and provide a synthetic approach to control these defect color centers for quantum information, imaging, and sensing.

Modified Composite Thermal Control Coatings Irradiatedwith High−Energy Particles

The main trends in modern space instrumentation are an increase in the active life of spacecraft, the tightness of their structure, and the widespread use of new polymer composite materials. Composite thermoregulatory coatings are designed to maintain the required thermal regime of objects by establishing a balance between the energy absorbed from the outside and the energy emitted into the environment. The aim of this work is to study the structure of new composite thermoregulatory materials (coatings) irradiated with high−energy particles − an electron with an energy of 3.5 MeV and a proton with an energy of 18 MeV, using X−ray diffraction analysis, optical photoluminescence doped with cerium, as well as other coatings, a new composition of thermoregulatory coatings (TRC) was developed by the method of hydrothermal microwave synthesis. According to the results of studies of modified TRCs, it was found that the samples synthesized by the microwave method have a crystalline structure after heat treatment. It is shown that the mechanisms of the effect of radiation spectra on the material medium are completely different and are determined by the atomic−molecular structure of matter. Irradiation with highly energetic particles gives rise to color defect centers of two types.

AUTOMATIC DETECTION OF SURFACE DEFECTS OF CERAMIC TILES

Ceramic tiles are one of the most demanded finishing materials, and the areas of their use are constantly expanding. The production of ceramic tiles is quite well automated, but the control of manufactured tiles for defects is usually not automated, that limits its speed and does not guarantee the necessary quality. The algorithm for detecting the main surface defects of ceramic tiles, namely, mechanical (scratches, cracks, etc.), geometric (chips on the corners, gouges or protrusions on the edges), color defects (blobs, spots, etc.) is proposed in the paper. It based on digital image processing of tiles and was implemented using the free library of algorithmic primitives OpenCV. The algorithm does not require the presentation of reference tiles. At the same time, a high speed of classifying monochrome tiles into fresh and defective ones is ensured and allows to organize the automatic control of plain tiles on the conveyor in real time with the probability of correct detections 97 %.

Implementation of Six Sigma Methods with Failure Mode and Effect Analysis (FMEA) as a Tool for Quality Improvement of Newspaper Products (Case Study: PT. ABC Manufacturing – Sidoarjo, East Java – Indonesia)

PT. ABC is a subsidiary of the JawaPos Group, founded in 1996, and is one of the companies in East Java engaged in printing and packaging. The products produced include magazines, books and newspapers. Of all the company's products, one of the most significant defects is found in newspaper products, which is 4% of the average newspaper production of 806.598 copies and produces a moderate defect of 22,743 copies in 2019. The research was conducted to analyze the sigma value and determine the factors of product defects and the impact of the defects to provide suggestions for product quality improvement. In this research, the method applied is the Six Sigma method and Failure Mode and Effect Analysis (FMEA), by implementing and carrying out the stages in the Six Sigma method, namely DMAIC (Define, Measure, Analyze, and Control). From this research, the results obtained are that the company has several newspaper product defects of 181,943 copies consisting of several types of product defects, including damp paper, blurred colours, shaded printing, asymmetrical printing, and running printing. The company is currently at the 4.04 sigma level, so corrective actions need to be taken to achieve six sigma levels. By applying the Failure Mode and Effects Analysis (FMEA) method, it can be seen that the most significant and most frequent product defect is the blurred colour defect. Therefore the recommended alternative solution for repairs is to check the ink and replace the ink with standard ink or have a lower density, perform regular and systematic machine checks, and provide further guidance on newspaper printing production standards to all operators involved.

Research on 3D MFL testing of wire rope based on empirical wavelet transform and SRCNN

Magnetic flux leakage (MFL) testing is one of the most effective methods in nondestructive testing of wire rope. However, traditional MFL testing devices have problems such as low recognition rate, single detection dimension and fuzzy magnetic leakage image. Based on the non-saturated magnetic excitation 3D MFL testing device, this paper proposes a wavelet denoising method based on empirical wavelet transform (EWT) to denoise the collected 3D MFL signal. After noise reduction, the Signal-to-Noise Ratio (SNR) and Root Mean Squared Error (RMSE) of the three dimensions have improved. Color imaging technology is used to fuse defect grayscale images into color images, and Super-Resolution Convolutional Neural Network (SRCNN) is applied to MFL images of broken wires. After SRCNN reconstruction, the resolution of defect color images is improved. The color moment feature of the defect color image is extracted as the input of the Elman neural network to quantitatively identify broken wires. Experimental results show that the noise reduction algorithm can effectively suppress the noise in three dimensions, and the broken wires recognition rate after reconstruction has been significantly improved, which verifies the effectiveness of SRCNN in wire rope MFL images.

Analisis Pengendalian Kualitas pada Pengolahan Produk Lemari Tipe MC11 01 dengan Metode Statistical Process Control pada PT Alis Jaya Ciptatama

Abstrak
 PT Alis Jaya Ciptatama is a manufacturing company that produces furniture made of mahogany and teak wood into furniture items. From the production data for the MC11 01 type wardrobe in August to September 2021, it reached 800 products with a percentage of cracking defects of 5% per year then knot defects of about 4% per year, and color defects of 1% per year, far from the defect tolerance limit of 1% at PT Alis Jaya Ciptatama resulting in a re-production process and additional production costs. In this study, the method used is Statistical Quality Control where the method is used to analyze what types of defects occur in the production of MC11 01 type cabinets, then look for factors causing defects in the product and provide suggestions for improvement. This method consists of Check Sheet, Stratification, Control Map, Pareto Diagram, Cause and Effect Diagram, Scatter Diagram, and Histogram.The results of this study indicate that the factors that occur in the MC11 01 type wardrobe product are human factors, machines, methods and materials. the biggest defect is crack with a total damage of 60 products or about 50%. Then followed by wood eye defects as much as 40 or about 33%, and color defects as much as 20 or about 16.7%. Proposed improvements should be made by reviewing the machine operation process, conducting employee training, implementing a reward and punishment system and working according to the SOP for the production process.

Engineering a mechanically stable hybrid photonic crystal cavity coupled to color defects in diamond

Wavelength scale photonic, high-quality factor (Q-factor), cavities are crucial for enhancing light–matter interaction. Such on-chip hybrid devices could potentially provide a route towards scalable quantum technologies with color defects in diamond. A variety of designs for photonic crystal cavities have been proposed; however, the challenging and multi-step fabrication processes required for such designs limit the experimentally observed Q-factors in addition to significant radiation loss. One possible way to minimize the radiation loss in a one-dimensional (1D) photonic crystal cavity is by introducing a so-called Gaussian defect region around the cavity. In this work, we propose a versatile approach to design a Gaussian defect region by changing the lattice parameter in a 1D photonic crystal. Further, to circumvent the problem of creating freestanding cavities for achieving high-Q factor in a 1D photonic crystal cavity, we propose a novel hybrid diamond-titanium dioxide (TiO2) based materials for color defects in diamond, in particular the nitrogen-vacancy (NV−) center. Our proposed mechanically stable and high-Q cavity could be crucial for on-chip integration of different nanophotonic components for chip-scale photonic devices. We show via simulations that Q-factor 105 can be achieved with the device.

Accelerated Aging of Epoxy Biocomposites Filled with Cellulose

The presented research concerns the mechanochemical modification of a snap-cure type of epoxy resin, A.S. SET 1010, with the addition of different amounts of cellulose (0, 2, 5, 10, 15 and 20 per 100 resin), for a novel, controlled-degradation material with possible application in the production of passenger seats in rail transport. Composite samples were prepared on a hydraulic press in ac-cordance with the resin manufacturer’s recommendations, in the form of tiles with dimensions of 80 × 80 × 1 mm. The prepared samples were subjected to thermo-oxidative aging and weathering for a period of 336 h. Changes in the color and surface defects in the investigated composites were evaluated using UV-Vis spectrophotometry (Cie-Lab). The degree of degradation by changes in the chemical structure of the samples was analyzed using FTIR/ATR spectroscopy. Differential scan-ning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were performed, and the sur-face energy of the samples was determined by measuring the contact angle of droplets. Tests were performed to determine changes in cellulose-filled epoxy resin composites after thermo-oxidative aging and weathering. It was found out that the addition of cellulose did not inflict sufficient changes to the properties within tested parameters. In the tested case, cellulose acted as a natural active biofiller. Our research is in line with the widespread pursuit of pro-ecological solutions in industry and the creation of materials with a positive impact on the natural environment.

Implementasi Metode Naive Bayes pada Sistem Pakar Diagnosis Penyakit Kutu Ikan Gurami (Argunus Indicus)

Gouramy is a freshwater fish that is widely cultivated by breeders and many experience death. Many deaths are caused by various diseases such as fungi and fish lice. The presence of disease in gouramy causes losses due to the number of deaths and can reduce quality such as freshness, color, and body defects which can affect the selling price of fish or economic value. Gouramy mortality data can reach up to 50%-100%. To reduce losses due to high mortality, an expert is needed to diagnose the disease. But the fact is that not all gouramy farmers understand how to diagnose fish, therefore an expert system is needed that can be used to help farmers to diagnose fish lice disease based on symptoms. The results of the system evaluation using 20 (twenty) fish symptom data obtained from carp breeders in 2021 which were compared with expert beliefs calculated using the confusion matrix table, the accuracy values were 94.2%, precision 95%, sensitivity 95% and specivity 93.3%. The evaluation results prove that Naïve Bayes has succeeded in providing good diagnostic results, so that the developed system can be used by fish farmers in diagnosing gouramy disease. Keywords: Gourami; Diagnosis; Fish Fleas; Naive Bayes; Expert system

Different surgical procedures for reconstruction of soft-tissue defects around the ankle

IntroductionManagement of soft tissue defects around the ankle is a difficult and challenging situation for all reconstructive surgeons. A microsurgical free flaps coverage can solve this problematic situation especially with large defects that is not available in all trauma centers. Moreover, long operating time and suitable operative demands are considered obstacles. Materials and methodEighty five patients having soft tissue defects around ankle were included in this study. They underwent various reconstructions in our specialized hand and reconstructive microsurgery unit from 2015 to 2019. Fifty two were males and thirty three patients were females. Road traffic accident was the main cause of injury in 66 patients followed by implant exposure in 15 patients and chronic osteomyelitis in 4 patients. Distally based superficial sural artery flap was used to reconstruct the defects in 21 cases, free flap was used in 32 cases, Rotational local flap was used in 8 cases, contralateral distally based superficial sural artery flap was used in 2 cases, full or partial skin flaps were used in 10 cases and Propeller flap was used in 12cases. ResultsAll flaps survived except for one modified sural flap with 98% success rate and average follow up of 48 months. All patients were satisfied with the functional capacity of operated limbs. Average time of bone healing postoperative was 3 months with gradual return to original work with acceptable degrees for cosmotic appearance of the limbs. ConclusionMany treatment options are available to cover defects around the ankle. Propeller and rotational flaps are fast and easy but cover small defects, distally-based modified sural artery flap is an excellent reliable flap. Microsurgical free flaps provide good contour, color, texture and cover large defects but require microsurgery facilities to execute.

Machine learning with knowledge constraints for process optimization of open-air perovskite solar cell manufacturing

Machine learning with knowledge constraints for process optimization of open-air perovskite solar cell manufacturing

A Computer-Based Farnsworth-Munsell 100-Hue (CFM-100) Test in Pilots' Medical Assessments.

OBJECTIVES: This study investigated the effectiveness and identified the cutoff values of the computer-based Farnsworth-Munsell 100-Hue (CFM-100) test for screening color vision deficiencies in the pre-employment examination of civil aviators in China.METHODS: Firstly, subjects were stratified into normal, color weakness, and color blindness with the Ishihara pseudoisochromatic plate test (IPPT) by two ophthalmologists. Then they randomly completed CFM-100 and Farnsworth-Munsell 100-Hue (FM-100) tests. Total error scores (TES) and the time taken for the CFM-100 and FM-100 were analyzed and the cutoff values for the CFM-100 were determined.RESULTS: Of 218 subjects, 159 were normal while 59 were diagnosed with dyschromatopsia. The TES of the CFM-100 were congruent with those of the FM-100 (20.0 ± 18.8 vs. 20.6 ± 17.7, 160.9 ± 66.0 vs. 151.1 ± 66.4). The testing time for the CFM-100, however, was less than the FM-100 (10.3 ± 2.8 min vs. 12.9 ± 2.9 min, 7.8 ± 2.5 min vs. 12.6 ± 3.3 min). The correlation coefficient R was 0.93 and Cohen's kappa was 0.89 for the two methods. Further analyses defined 34 as the cutoff value to differentiate excellent from fair color discrimination (sensitivity 58.0%, specificity 94.7%) and 101 as the cutoff value to judge fair vs. poor (sensitivity and specificity both 98.8%) for the CFM-100. The cut-off value was 72 for distinguishing normal from defective color vision (sensitivity 96.6%, specificity 98.7%) and 110 was for distinguishing color weakness from color blindness (sensitivity 97.6%, specificity 97.7%) for the CFM-100.CONCLUSIONS: The CFM-100 is an effective method for the diagnosis of dyschromatopsia with high sensitivity in screening airline pilots.Zhang Y, Ma J, Cheng S, Hu W. A computer-based Farnsworth-Munsell 100-Hue (CFM-100) test in pilots' medical assessments. Aerosp Med Hum Perform. 2022; 93(4):362-367.

A Novel Smartphone-Based Color Test for Detection of Color Vision Defects in Age Related Macular Degeneration.

Purpose To evaluate the efficacy of the smartphone-based K-color test to detect color defects in patients with Age-related Macular Degeneration (AMD). Methods 88 patients (n = 135 eyes) with AMD and 28 controls (n = 53 eyes) underwent color testing with the Hardy–Rand–Rittler (H-R-R), the K-color test, and the Ishihara test. The K-color test presents randomized colored shapes in decreasing steps of intensity, providing also a record system for result tele-transmission. Sensitivity, specificity, and reliability were examined to investigate the validity of the novel test. 26 participants with AMD also completed a questionnaire regarding the feasibility of the test. Results Linear mixed-effects models indicated a significant difference (p < 0.001) between AMD and normal eyes. The areas under the curve (AUC) were estimated to be 0.897 [95% CI: 0.841–0.952], 0.943 [95% CI: 0.901–0.984], and 0.931 [95% CI: 0.886–0.977] for the red, green, and blue color, respectively. Based on the H-R-R, the sensitivity of the test was 0.79, 0.90, and 0.95 for the red, green, and blue colors, respectively, and specificity was 0.88 for all colors. The new test recognized more abnormal cases than the Ishihara (sensitivity of 0.98 and 1.0 and specificity of 0.48 and 0.38 for red and green colors, respectively). Test-retest reliability was found to be high for the red [ICC = 0.996 (0.990–0.999)], green [ICC = 0.974 (0.929–0.990)], and blue [ICC = 0.992 (0.981–0.997)] colors. The majority of the asked participants stated that they could easily perform the test. Conclusion The K-color test was found to be sensitive and specific in detecting color defects in AMD patients. The K-color test may serve as a useful tool both for patients and their physicians.

Web-Based Integer Programming Decision Support System for Walnut Processing Planning: The MeliFen Case

Chile is among the largest walnut producers and exporters globally, thanks to a favorable nut growth and production environment. Despite an increasingly competitive market, the literature offers little scientific advice regarding decision support systems (DSSs) for the nut sector. In particular, the literature does not present optimization approaches to support decision-making in walnut supply chain management, especially the processing planning. This work provides a DSS that allows the exporter to plan walnut processing decisions taking into account the quality of the raw material, such as size, color, variety, and external and internal defects, in order to maximize the benefits of the business. To formalize the problem, an integer programming model is proposed. The DSS was implemented via a web application for MeliFen, a walnut exporter located near Santiago, Chile. A comparative analysis of the last two years revealed that MeliFen increased its profit by approximately 9.8% using this tool. We also suggest other uses that this DSS provides, besides profit maximization.

The mystery of the vision and its silent killer: A case report of optic neuropathy due to carbon monoxide poisoning

We report a case of a young, healthy male with sudden neurological collapse in the bathroom, presenting 3 weeks later with bilateral progressive dimunition of vision. Patient’s initial investigations including computed tomography (CT) brain was normal. At the time of presentation, he had severe visual impairment with defective colour vision and disc pallor bilaterally. Magnetic resonance imaging (MRI) brain was suggestive of carbon monoxide (CO) poisoning. A visual evoked potential (VEP) showed characteristic positive-negative-positive (PNP) waveform. Retrospective history confirmed the use of gas geysers in his bathroom. Patient was treated with intravenous steroids for 3 days followed by oral steroids to which he responded with improvement in visual acuity. Parenteral vitamin B12 was also administered. Optic neuropathy is a rare presentation of CO poisoning with very few cases reported in literature.

Synthesis, Characterization, Properties, and Novel Applications of Fluorescent Nanodiamonds.

In the last few years, fluorescent nanodiamonds (FNDs) have been developed significantly as a new member in the nanocarbon family. The surface of FNDs is embedded with some crystallographic defects containing color centres which surmount the properties of other fluorochromes including up conversion and down conversion nanoparticles, quantum dots, nano tubes, fullerenes, organic dyes, silica etc. Some of the intriguing properties like inevitable photostability, inherent bio-compatibility, outstanding optical and robust mechanical properties, excellent magnetic field, and electric field sensing potentiality make FNDs appealing to some benevolent applications in numerous fields like bio-imaging, delivering drugs, fighting cancer, spin electronics, imaging of magnetic structure at nanoscale and as promising nanometric temperature sensor. The structure of FNDs has certain point defects on the surface among which negatively charged nitrogen vacancy centre (NV-) is the most investigated color centre. The production of NV- fluorescence nanodiamonds is the most challenging task as substitution of carbon atoms is required to create vacancies by causing irradiation from an electron beam which is followed by high temperature annealing. Thus, this review points out the relative advantages of FNDs containing negatively charged nitrogen vacancy centres produced from HPHT method or CVD method with those nanodiamonds produced through detonation process or pulsed laser ablation (PLA) method. The steps involved in the fabrication of FNDs are described along with the major challenges and struggles underwent during the process in this review. This review also summarizes the recent developments made in the functionalization and applications predominantly made in the field of biological science and it is understood that depending on the defect color centres they can exhibit different emitted wavelengths ranging from UV-visible to near infrared with broad or narrow bandwidths. This review also highlights some of the fluorescent NDs that emit stable and strong red or green photoluminescence from the defect centers of NV- which are implanted in the crystal lattice. This critical and extensive review will be useful for the further progress in this futuristic field of FNDs.

Defective Coloring on Classes of Perfect Graphs

In Defective Coloring we are given a graph $G$ and two integers $\chi_d$, $\Delta^*$ and are asked if we can $\chi_d$-color $G$ so that the maximum degree induced by any color class is at most $\Delta^*$. We show that this natural generalization of Coloring is much harder on several basic graph classes. In particular, we show that it is NP-hard on split graphs, even when one of the two parameters $\chi_d$, $\Delta^*$ is set to the smallest possible fixed value that does not trivialize the problem ($\chi_d = 2$ or $\Delta^* = 1$). Together with a simple treewidth-based DP algorithm this completely determines the complexity of the problem also on chordal graphs. We then consider the case of cographs and show that, somewhat surprisingly, Defective Coloring turns out to be one of the few natural problems which are NP-hard on this class. We complement this negative result by showing that Defective Coloring is in P for cographs if either $\chi_d$ or $\Delta^*$ is fixed; that it is in P for trivially perfect graphs; and that it admits a sub-exponential time algorithm for cographs when both $\chi_d$ and $\Delta^*$ are unbounded.

Pattern of Colour Vision Anomalies Among Patients Presenting to a Tertiary Eye Center of Nepal

Introduction: Colour vision deficiency (CVD) is the inability to clearly differentiate colour differences under normal lighting condition. People are unaware of colour vision defect due to which they suffer in various aspects of their career. The purpose of this study was to explore the colour vision defect pattern among patients attending tertiary eye centre, Kathmandu, Nepal. Methods: A hospital based, retrospective study was conducted to evaluate the defective colour vision pattern in patients attending B.P. Koirala Lions Centre for Ophthalmic Studies, Institute of Medicine, Kathmandu, Nepal where total of 692 subjects medical case sheetswere reviewed and included in the study from September 2018 to April 2019. Results: Among 692 patients enrolled in the study, 272 (39.30%) patients were found to have CVD . Among 272 CVD,227(83.45%) were males and 45(16.54%) were females. Congenital colour vision defect was found in 139 (26.73%) males and 21 (13.81%) females. Acquired color vision defect was found in 88 (16.92%) males and 24 (15.78%) females . When congenital CVD was observed, deutan (28.3%) CVD was more prevalent than protan (22.79%) and tritan defect (7.72%). For acquired CVD, non-specific type of CVD (8.92%) was more prevalent followed by tritan CVD (5.35%). Conclusion: Significant proportion of patient presenting for eye care at tertiary eye hospital have color vision defects. Congenital CVD was found more in males than females whereas acquired color vision defect was found almost in same proportion in both males and females.

Liquid Chromatographic/Mass Spectrometric Study on the Role of Beech (Fagus sylvatica L.) Wood Polyphenols in Red Heartwood Formation

The present research focused on the analysis of European beech (Fagus sylvatica L.) wood polyphenols in respect to red heartwood formation, which is a significant color and technological defect of the species. For the first time, high-performance liquid chromatography/tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) were applied for the investigation of the structure and the radial distribution of polyphenols. Altogether 125 compounds were characterized by their MSn spectra, of which 71 were tentatively identified, including procyanidins (dimers to pentamers), flavonoids (taxifolin, naringenin, isorhamnetin, (epi)afzelechin), (+)-catechin, (−)-epicatechin) and their glycoside conjugates, phenolic acids (gallic acid, vanillic acid, syringic acid) and their glycosides as well as gallic acid derivatives, many of which were identified for the first time in beech wood. It was found that the concentration of many compounds increased at the color boundary. In situ polyphenol synthesis and metabolism were clearly evidenced at the color boundary. Red heartwood contained only free aglycones (syringic acid, taxifolin, naringenin, isorhamnetin, naringenin, syringic acid). Contrary to earlier assumptions, the MALDI-TOF analysis did not indicate the presence of oxidized high-molecular-weight polymeric polyphenols in the red heartwood tissues. The role of individual compounds in the formation of the red heartwood chromophores are discussed.