A Fundamentally New Colour Imaging Technology for Instant Photography

The Kodak instant print film is based on a fundamentally new colour-imaging technology. The imaging chemistry involves new types of compounds that release dyes for diffusion to a viewing region of the picture unit as a conse-quence of development of a new type of relatively high speed direct reversal emulsion. The chemical structures of the dyes were selected as a result of theoretical studies. The colour pictures produced by them feature a high level of colour fidelity.     

A Century of Progress In the Synthesis of Dyes for Photography

Dyes had no place in the Daguerreotype and other photographic processes in vogue a century ago. Today, dyes are vital not only to colour photography but also in much black-and-white photography. They are used as colour sensitizers, as desensitizers, for the prevention of halation effects, as filter layers in colour photography, in colour filters, and they constitute the coloured images in colour photographic processes. The development of these applications of dyes is reviewed in this paper.     

Communion and Disunion in the Work of Allan Sekula

What effect does a mounting technique have on a photograph? Zwelethu Mthethwa’s Interiors, a series of large colour photographs that depict residents of an informal settlement in Cape Town, offers a case study. In face-mounting the front of the photographic print is irreversibly bonded to Plexiglas. This has the effect of drawing the image to the surface, amplifying colours, and transforming the photographic print into a durable photographic object. Although largely unacknowledged in the critical literature, this material aspect of the photographs animates their utopian dimensions, shaping their intervention in the fraught politics of photographic representation in South Africa.     

The Preservation of Colour In Mounted Colour Prints

The main causes of dyes fading in photographic colour prints on paper or film are reviewed, and some suggestions to bear in mind while mounting colour prints, in order to reduce colour changes as far as possible, are described.     

Computerised Colour Matching for Litho Printing onto Metallic Surfaces*

At any given ink film thickness, the spectral reflectance of a colour litho print is dependent on the combined optical and spectral properties of the ink and substrate.

The theory and practice of computerised colour matching for litho printing onto metallic surfaces is described. A series of results covering different application areas is included together with a summary of the advantages and limitations of the system.     

Naturally functionalized silk as useful material for photonic applications

Silk is a natural fibre obtained from the Bombyx mori silkworm cocoons that can be used in a wide range of fields thanks to its inherent multifunctionality.Post-production steps are necessary to impart colour to the fibres to employ the material for optics and photonic applications, such as in fluorescence-based optofluidic devices in lab-on-a-chip realization.Here we present an intrinsically greener dyeing approach for fabricating naturally functionalized silk, where highly-fluorescent organic dyes with lasing properties are in vivo up-taken by silkworms once introduced in the artificial diet. A detailed photoluminescence spectroscopy investigation is implemented to test whether the dyes are effectively incorporated within the silk proteins, in correlation with the silkworm gland positions where proteins extraction is held. Light amplification characteristics are demonstrated in silk extracted from glands of silkworm fed with artificial diet doped with Rhodamine B dye.     

Cationization of cotton for industrial scale salt-free reactive dyeing of garments

Reactive dyeing of cotton garments involves two stages, namely exhaustion and fixation of dyes. The exhaustion stage in reactive dyeing requires high quantity of salt. After dyeing process, the highly saline coloured effluent is discharged and the treatment of this effluent at present is not economically viable and making industries look for other alternatives for usage of salt. Cationization of cotton is one of the effective alternatives to overcome the usage of the salt. The present work focuses on the exhaust method of cationization of garments at an industrial scale using 3-chloro-2-hydroxypropyl trimethylammonium chloride as a cationic agent. Two commercially popular reactive dyes namely Navy Blue and Green dyes were chosen for dyeing the garments at 10% shade. The results of dyeing were evaluated on the basis of colour strength, dyeing levelness and colour fastness. The uniformity of dye on the fabrics was evaluated based on dyeing levelness and was found to be good for cationized cotton dyed garments. The fastness properties of dyed fabrics to washing and light were good. The dye utilization in the cationized cotton dyed garments was twice as that of the conventionally dyed cotton garments. The environmental hazard posed by the highly saline coloured effluent could be easily mitigated by the salt-free reactive dyeing process.     

An eco-friendly option for less-chrome and dye-free leather processing: in situ generation of natural colours in leathers tanned with Cr–Fe complex

A chromium–iron tanning agent has been prepared and used for tanning with the objective of high exhaustion of chromium. Chromium–iron tanned leathers exhibit comparable shrinkage temperature and strength properties with those of conventional chromium tanned leathers. There is no change in strength or colour on ageing the leathers for 1 year. Spent tan liquor analysis reveals that the exhaustion of both the metals is more than 90%. Dyes based on synthetic formulations are being widely used in the leather industry. However, it is known that many aryl amine dyes are banned because of their carcinogenic nature. Environmental concern leads one to look for dyes based on natural resources. A novel approach has been taken to achieve an eco-friendly coloration process utilizing the presence of iron in the tanning salt, which gives rise to various colours on reacting with vegetable tannins. Skins have been tanned with Cr–Fe tanning salt and complexed with different vegetable tanning materials such as myrobalan and quebracho at various concentrations. Colours such as brown, black and grey have been developed. The colour shades obtained have been quantified by reflectance measurements. Thus, the study provides not only clean processes for a greener environment but also clean leather without harmful synthetic dyes. Electronic Publication     

基于打印头温度场模拟的织物打印工艺与性能

根据打印头尺寸和材料的热物性参数建立喷头传热模型,利用Solidworks Simulation插件对一定载荷温度条件下稳态传热进行了有限元分析,得到喷头打印稳态温度场。根据有限元分析结果并结合打印实验分析了基础组织(平纹、2/1右斜、5/3经面缎纹)结构的打印织物对其力学性能的影响。结果表明:小截面织物组织中浮长线越长,聚乳酸(PLA)材料本身性能利用率越高,成型质量佳,5/3经面缎纹织物的力学性能表现优异;交织点越多,结构发挥的效果越佳,平纹织物综合力学性能仅次于缎纹,斜纹织物力学测试性能最差;同时实验观察发现,打印层与层界面瞬态温度和层高对打印织物性能及外观也有影响,指明了存在的问题和进一步研究的方向。     

Bottleneck optical limiters: the optimal use of excited-state absorbers

Passive nonlinear absorptive limiters offer an effective means to protect human eyes and other focal-plane sensors from damage by pulsed laser radiation. New device designs are proposed in which dye molecules are driven into strong ground-state depletion by the incoming threat pulse while the internal fluence values are kept below the material failure level. Pulse-energy suppression ratios greater than 10(4) for 10-ns pulses together with linear transmission greater than 70% should be possible with existing dyes.     

Studies on degradation of reactive textile dyes solution by electrochemical method

The indirect electrochemical degradation of industrial effluents has become an attractive method in recent years. This paper deals with the electrochemical degradation of Novacron Deep Red C-D (NDRCD) and Novacron Orange C-RN (NOCRN) reactive azo dyes from aqueous solution using graphite carbon electrodes. The results indicated that initial pH, current density and supporting electrolytes were played an important role in the degradation of dyes. Electrochemical behavior of reactive azo dyes has been studied with cyclic voltammetry in acidic medium using pencil graphite as working electrode. The potentials selected for the two dyes were in the range +1.0 to -0.4V and +0.5 to -0.2V, respectively. The CV, UV-Vis and chemical oxygen demand (COD) studies were selected to evaluate the degradation efficiency. The maximum colour removal efficiency of 99% and 97% and chemical oxygen demand (COD) removal efficiency of 88% and 82% could be achieved for CDRCD and COCRN, respectively at 7 g L(-1) of NaCl concentration. The LC-MS study revealed the degradation of both the dyes and confirmed that the azo groups and aromatic rings were destroyed. The results revealed the suitability of the present process for the effective degradation of dye effluents.     

Stability of Selective Grey Obtainable by Use of Subtractive Colour Dyes

The optimum combinations of cyan, magenta, and yellow dyes in present-day subtractive colour photography have been investigated by means of a computer simulation method. The investigations have been carried out from the viewpoints of the stability of Selective greys against the illumination metamerism and also against the small changes of dye amounts.     

4D printing shape memory polymers for dynamic jewellery and fashionwear

4D printing is a novel approach that enables dynamic functionality in ordinary static object. We used a methacrylated semicrystalline polymer to print objects exhibiting thermally triggered shape memory behaviour. By exploring various molecular weights, it was found that a methacrylated polycaprolactone polymer with a number average molecular weight of 10,000?g?mol^?1 exhibited the best thermal and mechanical behaviour. The effect of dyes’ addition to the ink formulation on the photopolymerisation and on the printing processes was evaluated. The ink was utilised for demonstrating fabrication of dynamic jewellery and a shoe accessory by Digital Light Processing printing.     

Decolourization of azo dyes using magnesium-palladium system

Magnesium-palladium system was found to efficiently decolourize reactive black 5, sunset yellow FCF and tartrazine dyes. There is complete loss of visible range absorption peaks and extent of colour removal exceeded 95% within 24 h of reaction. There is appearance of new peak(s) in the UV region and/or gradual and significant shift of the lambda(max) in the UV range during 1-24 h of reaction of dyes with Mg/Pd system. LC-MS analyses following the reaction of dyes with magnesium palladium system suggest reductive cleavage of azo bonds and formation of amines as the end products. Kinetic analyses of dye decolourization indicate that the reaction follows first order kinetics. Agreement between the experimental and predicted Michaelis-Menten plots for the decolourization of reactive black 5, sunset yellow FCF and tartrazine dyes by Mg(0)/Pd(4+) system, suggests the correctness of Michaelis-Menten model for the prediction of dye decolourization rates by Mg(0)/Pd(4+) system. Our investigations reveal that Mg(0)/K(2)PdCl(6) system is more effective in decolourizing dyes as compared to Mg(0)/Pd(0)-alumina or Mg(0) alone. Results obtained from reuse experiments suggest that Pd(0) pellets have the potential for recycling which will make the treatment process cost effective. Mg(0)/Pd(4+) system was found to be efficient in decolourizing mixture of drimarene, remazol and procion dyes as well as raw effluent generated by textile dye manufacturing company.     

Couplers in colour photography—chemistry and function Part 2

Abstract

Part 2 deals with magenta and cyan couplers and—in addition—white couplers and scavengers, centred about the years between 1960 and 2000 as in Part 1.

Magenta couplers have been a domain of heteroaromatic compounds. This fundamental situation has not changed, except for the fact that the predominance of pyrazolone type magenta couplers has been broken. Today, 3-acylamino- and 3-anilinopyrazolones are still used, but mainly in colour negative film, and pyrazolotriazoles of the pyrazolo[5,1-c](1,2,4)triazole and pyrazolo[1,5-b](1,2,4)triazole classes have taken a larger share, despite the fact that suitable syntheses had to be explored for both classes.

In colour negative (CN) paper, where the lower reactivity level of pyrazolotriazoles does not really bother, the inherently clean absorption and high tinctorial strength of the azomethine dyes from pyrazolotriazoles plays an important role. While the stability level of azomethine dyes from 3-anilinopyrazolones was considerably improved between 1960 and 1980, it does not compare favourably to the stability achieved today by azomethine dyes from pyrazolotriazoles. This applies equally to stain resistance, light fading and dark fading.

Within the anilinopyrazolone series, valuable two-equivalent couplers have been found by the introduction of arylthio groups as leaving groups. Within the acylaminopyrazolones this has been achieved by the introduction of pyrazoles as leaving groups. The chemical problems encountered in these—and in comparable, but less successful—transformations must not be underestimated. Within the pyrazolotriazole classes, chlorine presents itself as a trouble-free and readily introduced leaving group.

Throughout the years, phenols and naphthols have been used as cyan couplers. For both classes of cyan couplers a strong need for improvement in dye stability was recognized. In CN film, the cyan dyes from 1-hydroxy-2-naphthoic amides showed low resistance to reduction by exhausted bleaches and were replaced by 2-phenylureido-5-acylaminophenols or 5-amino-substituted 1-hydroxy-2-naphthoic amides. In CN paper, 2-acylamino-4,6-dichloro-5-methylphenol type cyan couplers were replaced by 2-acylamino-4,6-dichloro-5-ethylphenols which show high stability to light fading. Thus, improved dark fading resistance of the cyan dye in colour paper has turned out to be a major objective of continued chemical research.

Research on, among other options, the field of polyazapentalenes, a large group of bicyclic acidic heteroaromatic compounds, comprising also the well-known pyrazolotriazoles, has yielded some classes of new heterocyclic cyan couplers giving cyan dyes of outstanding tinctorial strength and absorption, of which the pyrrolo[1,2-b](1,2,4-triazoles) are the most prominent examples. The dyes from presently known pyrrolotriazole couplers are stable to dark fading, but they need some improvement in light stability. An entirely different approach to solving the dark stability problem without any sacrifice in hue and light stability has been found within the class of 2,5-diacylaminophenols, by introduction of a sulphone-modified acyl group.

White couplers and scavengers are expected to function without additional problems, and in most cases do. Nevertheless, the compounds under discussion are interesting under theoretical aspects. True white couplers, e.g. of the 4-methylpyrazolone class, show incomplete coupling and do not fix the developer residue permanently: it can be shown to be split off by oxidation. Scavengers of the 2,4-disulphonamidophenol class and also of the 2,5-disulphonamidophenol class do not show the coupling reaction of a two-equivalent coupler; instead they undergo electron transfer to an oxidized colour developer.     

自扫描光电二极管阵列光电信号测量系统及其测试实例的研究

本文介绍了一种利用自扫描光电二极管阵列(SSPDA)图象传感器作为光电转换器件,可用于大面积显示器件图象质量评价和测微领域的测量系统。该系统由光学成象、SSPDA图象传感器、数据采集、接口电路和微型计算机等部分组成,能对各种被测量参数进行处理,并打印出数据和曲线。通过对彩色显象管(CPT)的线宽、三束间距以及光学狭缝等的测试,该系统显示了足够的测量精度。     

电子暗房技术运用于指纹司法鉴定中之研究

目的通过利用电子暗房处理技术—Photoshop计算机图形处理软件对现场指纹和嫌疑人捺印指纹进行图像处理，达到指纹鉴定及其材料制作的目的。方法首先利用扫描仪将指纹扫描输入计算机，然后利用Photoshop对指纹检材与样本进行图像处理和检验鉴定。结果Photoshop不仅可以处理指纹鉴定图像，而且可以处理其它痕迹鉴定的图像。如：足迹、工具痕迹、枪弹痕迹、文件检验等等。结论本研究对实际应用有较大的参考价值。     

Synthesis and application of p-tert-butylcalix[8]arene immobilized material for the removal of azo dyes

The present study describes synthesis of a new resin through immobilization of p-tert-butylcalix[8]arene onto silica and its application for the removal of azo dyes from aqueous media as well as from textile effluents. The newly synthesized material 4 is characterized by FT-IR spectroscopy, scanning electron microscope (SEM) and thermogravimetric analysis (TGA). Reactive Black-5 (RB-5) and Reactive Red-45 (RR-45) azo dyes were used as sorbate. Batch wise sorption experiments were conducted to optimize various experimental parameters such as the effect of sorbent dosage, electrolyte, pH, dye concentration, and contact time. The optimized pH for the effective removal of RB-5 and RR-45 dyes was 9 and 3, respectively. The increase in material 4 dosage increased the percent sorption. Both Langmuir and Freundlich isotherm models were applied to experimental data and Langmuir isotherm model found to be best fit. The results revealed that material 4 was potentially more effective sorbent for the sorption of selected azo dyes as compared to pure silica and p-tert-butylcalix[8]arene. The field studies also supported the effectiveness of material 4, which could be useful for the removal of both the dyes and also for the normalization of pH, TDS, conductivity and salinity near to the drinking water.     

Two Masks for Halftone

In colour masking for continuous tone processes, the number of masks which is generally required can be reduced if the unwanted densities of the dyes are suitably related to each other. In particular, in a process employing dyes which have three unwanted densities (the yellow having no densities to red and green light and the magenta no density to red light) the three masks required can in certain cases be reduced to two. A suggestion that a similar simplification might be achieved in the masking procedure for halftone processes outlined in a previous paper is examined, and it is concluded that if the unwanted densities of the inks obey the condition which allows the reduced number of masks in a continuous tone process, then the same number of masks in a halftone process should give results which differ only little from those obtainable with the more correct full number of masks.     

Colour Reproduction as a Function of Tone Scale in Negative-Positive and Reversal Systems

The object of this study is to provide o method for simulating the whole process of colour reproduction in a mathematical way, so that at any moment well-chosen changes can be introduced into the different steps of this process. This approach provides certain possiblities, when testing the quality of colour reproduction by colour material, which are not yet afforded with the required accuracy by empirical means.