Cultural and architectural heritage conservation and restoration: which colour?

Colours play a crucial role in the field of architectural heritage. Colour analysis and colour rendition are involved in several critical facets of heritage preservation, conservation and restoration. These aspects are related to accurate documentation and an accurate representation of heritage artefacts and architectural works. The aim of this paper is to describe critical issues and open problems of the processes involved in this field. Documentation is performed in multiple ways, acquiring heterogeneous data ranging from archival images, photographs, drawings using various consumer or professional instruments (eg, digital cameras and spectrophotometers). The reliability of colour acquisition might be influenced by instrumental reasons (the technology used to acquire colour information), by environmental changes (architectural heritage surveys are often performed outdoors), by morphology (complex architectural objects are characterised by concavities and convexities which complicate the reflection evaluation), or by materials (showing different reflection, porosity and transparency indexes). Identification of materials, such as colorants, pigments and dyes, is also a vital process in the heritage field. Colour information could be used as an approach to the identification of materials, but these methods are still under development, and many issues need to be solved to achieve reliable results. Visualisation techniques of a heritage artefact also present the problem of the correctness of the colour representation. Several problems need to be faced in this context: the reliability of the acquisition, colour management of the rendering software, model complexity, and fragmentation of the devices upon which the model is visualised.     

分散染料染色物若干色牢度问题分析和改进技术

近年涤纶染色物的变褪色和落色等色牢度问题以及色点、色斑等是分散染料存在的主要问题之一,本文分析了产生这些问题的原因与改进技术.     

我国多彩涂料的现状与发展趋势

本文论述了多彩涂料的发展历程、现状及目前生产中存在的问题，并指出我国多彩涂料的发展方向是开发水包水型多彩涂料。     

Virtual colour: Communication standard and analytical tool

A number of problems have been identified with existing colour specification systems and their physical exemplifications: colorimetric conditions (illuminant, observer, spectrophotometer geometry, specular component inclusion/exclusion, etc.), restrictions of the notational system adopted, and limitations of the colour atlases themselves (sample size, sample error, sample range, etc.). Developments in computer science, and in particularly CRT displays and colour printing devices, now provide increasingly more affordable alternatives to traditional colour ranges and atlases. Techniques have been developed to increase the accuracy of printed colours relative to their CRT originals, and devices are manufactured to calibrate colour monitors. However, colour selection software developed to date is still primarily based on existing colour ranges and colour specification systems, or on a more general mechanism specific to an individual application. It is argued that basing such software on an existing model of colour specification inherits some of the problems of that system: notational methodology, means of representation, and atlas limitations. It is proposed that the restrictions imposed by such software be relaxed by providing a flexible method of constructing application-specific colour specification systems with conversion to a standardized notation for accurate colour communication. Furthermore, it is proposed that such a tool would be invaluable for the evaluation of human colour perception. © 1997 John Wiley & Sons, Inc. Col Res Appl, 22, 204–211, May 1997.     

The Use of Colour–difference Formulae in the Leather Industry

There has been an interest in colour measurement and the measurement of colour differences for a considerable number of years in the leather industry. A brief outline of their use and of the related problems is given and the application of colour–difference equations to matching, sorting and specifications is reviewed. Particular attention is drawn to the fact that no single colour–difference formula is likely to be acceptable for all productions of leather.     

How colour‐deficient observers see things,or not.

Colour deficiency or, colloquially, colour blindness, is common and has been observed and described in the scientific literature for ca. 200 years. In more recent times, algorithms have been developed that simulate the effect of colour deficiency to a colour‐normal observer. Sometimes these algorithms are used to indicate potential problems in the colour design, but often the implicit assumption is that a colour‐deficient observer actually sees things that way. But do they? This paper questions some of the underlying assumptions of the algorithms.     

The Specification of Colour Appearance. II. Effects of Changes in Viewing Conditions

The effects on colour appearance of changes in surround, illuminant colour, absolute luminance level, and field size are considered. Methods are discussed whereby existing formulae can be used or modified, and new formulae devised, to obtain measures that correlate with the colour attributes involved. Examples of the application of such formulae to practical problems in illuminating engineering and in television are considered briefly. (In Part I the basic concepts and terms necessary for the specification of colour were considered.)     

Requirements capture for colour information for design professionals

This article presents the results of a study that investigates the status of colour information use in the design process and generates ideas for a colour tool. Face‐to‐face interviews with senior designers and brand managers from the packaging and branding fields were conducted as the primary data collection method. The results are categorized into six topics: colour decision, types of colour information considered to be important in the design process, reasons for considering colour information important in the design process, current use of colour information, design professionals' preferences for existing colour tool types and data types and suggestions for a colour tool. It is concluded that there are problems with existing colour resources and tools regarding their availability and usefulness; there is a strong demand for a colour tool in the packaging design and branding processes. The insight from this work will help researchers, design professionals and colour tool developers to make informed decisions on the areas on which they should focus, how they should do so and why. This will facilitate better provisions and uptake of useful colour information for design professionals in the design process and strategy fields.     

Different matrices for CIECAM02

CIECAM02 has been used to predict colour appearance under a wide range of viewing conditions, to provide a uniform colour space, and to provide a profile connection space for colour management. However, some problems have been identified with CIECAM02. CIE Technical Committee 8‐11 is currently working on the methods to resolve the problems for practical applications. Part of the CIE TC8‐11 work is to repair the lightness computational failure. This article incorporates most of the previous suggestions and makes some further tests. It is hoped that this article will aid the ongoing work of the CIE TC8‐11 and perhaps be the starting point for repairing the CIECAM02 for colour management and for the new recommendation. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 143–153, 2014     

色母粒及填充母粒生产与研究现状

根据近年来有关色母粒与填充母粒的研究报道,对颜填料预处理、母粒制备及性能进行了综合讨论,分析了色母粒与填充母粒生产和研究过程中存在的问题,并就母粒的发展提出了新的认识,为今后色母粒与填充母粒的研究开发提供借鉴。     

Colour fragmentation measurement in a historic area: Using Shanghai Old Town as an example

Under the background of urban renewal protection and old city transformation, problems such as clutter, distortion, and disorder appear in the historical style area. These problems have greatly impacted and damaged the cultural heritage and historical research of the style area. To carry out the urban renewal movement more reasonably, this article selects the historical features of the Old Town of Shanghai for empirical research, uses the colour patch concept and fragmentation index for a quantitative analysis, and divides the study area fragmentation level. The study found that the number and types of colour patches in the Old Town are many, and the yellow system is highly fragmented in the Old Town, which means that the human environment in the colour style area is lost. The main reasons are the rise of modernist architecture and new materials. Three aspects are involved in the widespread use of policy and out-of-control management of the policy; therefore, attention should be paid to the updating of future historical style areas: protecting the authenticity of colours, maintaining colour integrity, and continually retaining colour memories in cities.     

Optimal yarn colour combination for full‐colour fabric design and mixed‐colour chromaticity coordinates based on CIE chromaticity diagram analysis

It is challenging for textile designers to achieve full‐colour effects in woven fabric using a limited set of coloured yarns. The common problems encountered during full‐colour fabric design include an insufficient number of colours and a failure to match the fabric colour with the desired colour. Using the theories of primary colours and optical colour mixing, we examine the mixed‐colour distribution of primary colour yarns on the basis of the CIE 1976 chromaticity diagram (CIE u′v′). In our experiment, dope‐dyed polyester filament yarns were selected as raw materials. Eight kinds of gradually varied weave structures and four types of primary colour combination were adopted in order to make different types of full‐colour fabric colour chart. Spectrophotometer and DigiEye colour measurement systems were selected to measure the reflectance and colour value of the fabric samples. By comparing the colour distribution of mixed fabrics in the CIE u′v′ diagram, the relationship between the primary colour combinations and the colour distribution of mixed fabrics is discussed. Of RGB, CMY, NCS, and RGBCMY combinations, only RGBCMY resulted in a relatively complete and large colour gamut. Moreover, the colour positions of mixed fabrics in the CIE u′v′ diagram were almost all distributed on or near the connecting line of the primary colour coordinates. The specific colour position of mixed fabrics in the CIE u′v′ diagram were mainly determined by the proportion of primary colours on the fabric surface. In this way, a new method for computing colour position in the CIE u′v′ diagram is introduced.     

壬基酚变色综合分析

本文详细分析了壬基酚变色的原因，并提出了有效防止比色指数上升的措施，应用效果显著。本文同时提出了新的问题。     

CMC 2000 chromatic adaptation transform: CMCCAT2000

CMCCAT97 is a chromatic adaptation transform included in CIECAM97s, the CIE 1997 colour appearance model, for describing colour appearance under different viewing conditions and is recommended by the Colour Measurement Committee of the Society of Dyers and Colourists for predicting the degree of colour inconstancy of surface colours. Among the many transforms tested, this transform gave the most accurate predictions to a number of experimental data sets. However, the structure of CMCCAT97 is considered complicated and causes problems when applications require the use of its reverse mode. This article describes a simplified version of CMCCAT97— CMCCAT2000—which not only is significantly simpler and eliminates the problems of reversibility, but also gives a more accurate prediction to almost all experimental data sets than does the original transform. © 2002 John Wiley & Sons, Inc. Col Res Appl, 27, 49–58, 2002     

Systems approach expands benefits and eliminates problems with liquid colour

There are many advantages associated with the use of liquid colour, but there is also the potential for handling complications and plant-floor mess. A new comprehensive colour-management system available to North American processors eliminates these problems and saves costs, according to Riverdale Color's president Chuck Irish. In addition, he argues, processors can achieve even greater cost savings by using liquid colour with gravimetric blenders.     

Roadmap of moving urban colour toward cultural sustainability in China

With the gradual refinement of urban space in China, the aesthetic quality of the urban visual environment has been getting more attention. Urban colour, one of the visual aesthetic elements, is a significant carrier of urban characteristics, sociocultural and history in cultural policies. As a type of cultural capital, it provides creative methods to approach problems of economic, environmental, social, and especially cultural sustainability. The interdisciplinary theory of urban planning is innovatively applied to guide, coordinate, and advance the sustainable production of urban colour in China. The objectives of this study are to: (a) explain the way urban colour is produced through the urban planning system in Chinese context; (b) elaborate affecting factors related to urban colour sustainability from the perspective of planning strategies and cultural policies; (c) propose sustainable planning strategies of urban colour production. To answer the above questions, we reviewed over 200 articles, plans, and official documents, and conducted several semi‐structured interviews. The results show that the Chinese municipal government has regarded urban planning strategies and policies as a strategic tool for achieving sustainable urban colour development. Our discoveries would expend the research and application on the aesthetics of cities through the contextual analysis of Chinese urban colour planning system. By exploring the points of planning strategies and cultural policies, it also fills gaps in the literature on the sustainability of urban colour.     

我国色母粒的生产现状与发展趋势

本文介绍了我国色母粒的生产现状、存在的问题及今后的发展趋势,并提出了一些建议。     

客车涂装中有关问题的探讨

讨论了客车涂装过程中．腻子、底漆、金属闪光漆、面漆及彩条等方面的材料和施工工艺中的问题和解决方法,并讨论了涂层外观评价方法。     

Why higher resolution graphics cards are needed in colour vision research

The colour resolution of a 14‐bit and an 8‐bit per channel graphics card were evaluated and compared with the just noticeable difference between colours (varying only in luminance) for: (1) a standard observer (based on the CIE 1976 L*u*v* colour space) and (2) real observers in a colour discrimination task. The results of this study show that an 8‐bit per channel graphics card seems adequate for colour discrimination experiments where stimuli only vary in luminance. However, considering that the resolution of the graphics card should be equal to the Nyquist rate, an 8‐bit per channel card turns out to be inadequate. For colour discrimination experiments where stimuli only vary in chromaticity, there is an undersampling of the colour space with respect to MacAdam ellipses when using 8‐bit per channel graphics cards. The extremely fine colour resolution of a 14‐bit per channel graphics card overcomes these problems. Its use allows more accurate measurements of achromatic and chromatic discrimination thresholds and avoids experimental (spatial or luminance) artefacts, such as bandings that can occur on achromatic or chromatic gradients. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011     

Colour-distance judgement and the influence of the background in colour reproduction

The influence of the background in colour reproduction can be described in colorimetric terms by the use of corrections to the colorimetric scaling factors. This leads to transformation formulae that describe the change of chromatic adaptation, and also to an extended definition of the so-called “colour of the state of chromatic adaptation.” The method leads to an improved reconciliation between the specification of colour-rendering properties in both colour photography and multicolour printing and the visual evaluation. Certain problems in colorimetry may also become more easily understandable by the incorporation of such peripheral influences. Whereas the physiologically related scaling-factor corrections are of first-order importance, it is shown that stray-light effects, which are physical contributing factors, are only of the second order.