Experiments in inkjet colour tests for printmaking

The motivation for this research is based on how artistsmix and print colour by traditional means (painting andprintmaking) and how these differ from colour picker tools,slider bars and methods developed for digital printing, andwhether it is possible to incorporate both? Artists have been expert at mixing colour for centuries, yet although the artist and designer has access to a wide range of digital imaging tools and technologies, that on first glance, are dedicated to the creation of colour mixtures, the resulting colours are often disappointing. It appears that hardware, software tools and methods for digital printing are not necessarily suited to the specific requirements of the artist. In fact, they are toogeneralised to obtain a high degree of quality and too inflexible to allow artists to obtain precision and predictability. Based on existing hardware and software, the paper suggests alternative approaches to custom colour ink mixing and printing. Through the development of alternative ink colours specifically mixed for inkjet printing the paper demonstrates specially designedcharts for printing and double printing of custom mixed inks

The material image: Artists’ approaches to reproducing texture in art

Since the introduction of computers, there has been a desire to improve the appearance of computer-generated objects in virtual spaces and to display the objects within complex scenes exactly as they appear in reality. This is a straightforward process for artists who through the medium of paint or silver halide are able to directly observe from nature and interpret and capture the world in a highly convincing way. However for computer generated images, the process is more complex, computers have no capability to compare whether the rendering looks right or wrong—only humans can make the final subjective decision. The evolving question is: what are the elements of paintings and drawings produced by artists that capture the qualities, texture, grain, reflection, translucency and absorption of a material, that through the application of coloured brush marks, demonstrate a convincing likeness of the material qualities of e.g.wood, metal, glass and fabric? This paper considers the relationship between texture, objects and artists’ approaches to reproducing texture in art. However texture is problematic as our visual system is able to discriminate the difference between natural and patterned texture, and incorrectly rendered surfaces can hinder understanding. Furthermore to render surfaces with no discernible pattern structure that comprises unlimited variations can result, as demonstrated by the computer generated rendering, in exceptionally large file sizes. The paper explores the relationship between imaging, artists’ approaches to reproducing representations of the attributes of material qualities, the fluid dynamics of a painterly mark, and 2.5D relief in printing. The objective is not to reproduce existing paintings or prints, but to build the surface using a deposition of pigments, paints and inks that explores the relationship between image and surface

Colour coded

This 300 word publication to be published by the Society of Dyers and Colourists (SDC) is a collection of the best papers from a 4-year European project that has considered colour from the perspective of both the arts and sciences.The notion of art and science and the crossovers between the two resulted in application and funding for cross disciplinary research to host a series of training events between 2006 and 2010 Marie Curie Conferences & Training Courses (SCF) Call Identifier: FP6-Mobility-4, Euros 532,363.80 CREATE – Colour Research for European Advanced Technology Employment. The research crossovers between the fields of art, science and technology was also a subject that was initiated through Bristol’s Festival if Ideas events in May 2009. The author coordinated and chaired an event during which the C.P Snow lecture “On Two Cultures’ (1959) was re-presented by Actor Simon Cook and then a lecture made by Raymond Tallis on the notion of the Polymath. The CREATE project has a worldwide impact for researchers, academics and scientists. Between January and October 2009, the site has received 221, 414 visits. The most popular route into the site is via the welcome page. The main groups of visitors originate in the UK (including Northern Ireland), Italy, France, Finland, Norway, Hungary, USA, Finland and Spain. A basic percentage breakdown of the traffic over ten months indicates: USA -15%; UK - 16%; Italy - 13%; France -12%; Hungary - 10%; Spain - 6%; Finland - 9%; Norway - 5%. The remaining approximate 14% of visitors are from other countries including Belgium, The Netherlands and Germany (approx 3%). A discussion group has been initiated by the author as part of the CREATE project to facilitate an ongoing dialogue between artists and scientists. http://createcolour.ning.com/group/artandscience www.create.uwe.ac.uk.Related papers to this research: A report on the CREATE Italian event: Colour in cultural heritage.C. Parraman, A. Rizzi, ‘Developing the CREATE network in Europe’, in Colour in Art, Design and Nature, Edinburgh, 24 October 2008.C. Parraman, “Mixing and describing colour”. CREATE (Training event 1), France, 2008

How to print a rainbow

In the 21st century, methods for translating additive colours as seen on screens (Red Green Blue (RGB)) into subtractive colours (Cyan Magenta Yellow Black (CMYK)) for industrial print are based on 4 colour halftoning. CMYK are so called process colours, used for printing on opaque substrates, from paper to glass and metal, when photomechanical reproduction is desired. These reproductions surround us, from images in books and magazines, on packaging to prints on clothing, homeware and advertising banners. Additive RGB colours are traditionally used in transmittance, i.e. in backlit applications, for example in mobile phones, laptops, tablets etc. SpectravalTM pearlescent pigments produced by Merck open the possibility of RGB, i.e. additive, colour printing on opaque substrates. We present here a characterisation of the optical features of these effect pigments and discuss print applications

Reflectance, illumination, and appearance in color constancy

We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor's reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation. © 2014 McCann, Parraman and Rizzi

Printing the light

This paper explores the relationship between additive and subtractive mixing for colour printing. Using Spectraval mica pigments (Merck)—marketed as RGB pigments—colour is generated by selective reflection and prints are based on additive colour mixing principles, that when printed onto black paper, create white and a range of colours. Although currently used mostly for decorative effects, they can be the basis of additive 'process' inks, that present new opportunities for and challenges to traditional print markets. The viewing angle dependency of their selective reflection favours applications in security printing similar to the holograms on bank cards for example. Traditional measurement and modelling methods are difficult to apply due to the layering and irregular dispersion of pigments

The Amber Project: A survey of methods and inks for the reproduction of the color of translucent objects

Unlike regular pigments based on selective light absorption, the so-called “effect pigments” are based on the phenomena of structural color, or selective reflectance. Structural color has appealing aesthetic qualities, such as angle-dependent hue, and is able to produce lightfast colors. When used as a pigment, however, the gamut of the print is more limited, the color is difficult to measure, and therefore color management and preprint process become challenging. The aim of this paper is to compare the behavior of effect pigments in the processes of lithographic and screen printing with standard pigments used in so-called process inks, and to analyze their optical properties when used on their own or in combination with absorption pigments. An image of amber beads was printed as screen prints and lithographs. Three sets of inks were used: Set one: Standard process inks in the colors cyan, magenta, yellow and black (CMYK); set two: RGB inks formulated with Merck Spectraval™ pearlescent pigments which allow additive red, green, blue printing on a black substrate; and set three: golden inks formulated with pigments from the Merck Iriodin™ and Pyrisma™ effect pigment range. The image was printed on white and black paper. The optical appearance was assessed visually, and spectra and color coordinates were measured

Retrieving the ancient colours: Artistic practice as a tool for heritage reconstruction

The frieze of the Palace of the stuccoes, dated between the 5 th and 6 th century BC, was a polychrome Maya relief discovered in the 1907 in Yucatán, Mexico. It was documented in watercolours and hand tinted photographs by Adela Breton. After years of exposure to the harsh environmental conditions of the Maya area, the colours and the stucco relief disappeared. The aim of the project is to develop a hybrid digital-analogue printing method for reconstructing the appearance of the original polychrome relief based on digitised handmade records. A description of the process to produce full colour images combining digital and photomechanical printing is provided. Using photopolymer plates, an intaglio printing process has been used to produce colour images, whilst inverse relief plates have been created based on height maps to transfer a positive embossing on paper when applying pressure on a printing press. The influence of physical parameters related to the appearance is studied. Reflectance Transformation Imaging was carried out to record the colour and surface shape of the prints. Measurements of gloss were made on relief inkjet prints and intaglio prints on paper to compare the outcomes of commercial 2.5D print and the method proposed here. By modifying an analogue process with digital technology, it is possible to incorporate ancient materials to the printmaking process and therefore approach naturally the appearance of the original. On the other hand, incorporating imaging techniques and quality measurements enables to improve the quality in analogue printing techniques

Printing with tonalli: Reproducing featherwork from precolonial Mexico using structural colorants

Two of the most significant cases of extant 16th-century featherwork from Mexico are the so-called Moctezuma’s headdress and the Ahuizotl shield. While the feathers used in these artworks exhibit lightfast colors, their assembly comprises mainly organic materials, which makes them extremely fragile. Printed media, including books, catalogs, educational materials, and fine copies, offer an accessible means for audiences to document and disseminate visual aspects of delicate cultural artifacts without risking their integrity. Nevertheless, the singular brightness and iridescent colors of feathers are difficult to communicate to the viewer in printed reproductions when traditional pigments are used. This research explores the use of effect pigments (multilayered reflective structures) and improved halftoning techniques for additive printing, with the objective of enhancing the reproduction of featherwork by capturing its changing color and improving texture representation via a screen printing process. The reproduced images of featherwork exhibit significant perceptual resemblances to the originals, primarily owing to the shared presence of structural coloration. We applied structure-aware halftoning to better represent the textural qualities of feathers without compromising the performance of effect pigments in the screen printing method. Our prints show angle-dependent color, although their gamut is reduced. The novelty of this work lies in the refinement of techniques for printing full-color images by additive printing, which can enhance the 2D representation of the appearance of culturally significant artifact

Bristol and Bath by Design; To understand the economic and cultural value of design in the Bristol and Bath region

The aim of the project was to collect data on designcompanies in the Bristol and Bath region, and to gain abetter understanding of the economic and cultural valueof the design-led sector. To do this, our primary researchwas to develop a range of qualitative and quantitativemethods that could gather and then analyse the data