Limited Palette Research Articles

Lossy Image Compression with Stochastic Quantization

Introduction. Lossy image compression algorithms play a crucial role in various domains, including graphics, and image processing. As image information density increases, so do the resources required for processing and transmission. One of the most prominent approaches to address this challenge is color quantization, proposed by Orchard et al. (1991). This technique optimally maps each pixel of an image to a color from a limited palette, maintaining image resolution while significantly reducing information content. Color quantization can be interpreted as a clustering problem (Krishna et al. (1997), Wan (2019)), where image pixels are represented in a three-dimensional space, with each axis corresponding to the intensity of an RGB channel. The purpose of the paper. Scaling of traditional algorithms like K-Means can be challenging for large data, such as modern images with millions of colors. This paper reframes color quantization as a three-dimensional stochastic transportation problem between the set of image pixels and an optimal color palette, where the number of colors is a predefined hyperparameter. We employ Stochastic Quantization (SQ) with a seeding technique proposed by Arthur et al. (2007) to enhance the scalability of color quantization. This method introduces a probabilistic element to the quantization process, potentially improving efficiency and adaptability to diverse image characteristics. Results. To demonstrate the efficiency of our approach, we present experimental results using images from the ImageNet dataset. These experiments illustrate the performance of our Stochastic Quantization method in terms of compression quality, computational efficiency, and scalability compared to traditional color quantization techniques. Conclusions. This study introduces a scalable algorithm for solving the color quantization problem without memory constraints, demonstrating its efficiency on a subset of images from the ImageNet dataset. The convergence speed of the algorithm can be further enhanced by modifying the update rule with alternative methods to Stochastic Gradient Descent (SGD) that incorporate adaptive learning rates. Moreover, the stochastic nature of the proposed solution enables the utilization of parallelization techniques to simultaneously update the positions of multiple quants, potentially leading to significant performance improvements. This aspect of parallelization and its impact on algorithm efficiency presents a topic for future research. The proposed method not only addresses the limitations of existing color quantization techniques but also opens up new possibilities for optimizing image compression algorithms in resource-constrained environments. Keywords: non-convex optimization, stochastic optimization, stochastic quantization, color quantization, lossy compression.

Business Data Visualization, Beyond the Boring.

Business uses of charts and visualizations, and by extension business users, are usually considered mundane and boring. But they, too, want to get their audience's attention, emphasize a point they are making, or simply break out of the monotony of the limited palette of common chart types. I believe that there is ample opportunity to develop new approaches and build better tools that go far beyond the current one-size-fits-all approach to creating charts-much more than is currently recognized in the visualization community. The first step is to reexamine our notions of who business users are, and what they actually want and need.

Recent Advancements towards Sustainability in Rotomoulding.

Rotational moulding is a unique low-shear process used to manufacture hollow parts. The process is an excellent process method for batch processing, minimal waste and stress-free parts. However, the process has drawbacks such as long cycle times, gas dependency and a limited palette of materials relative to other process methods. This review aimed to shed light on the current state-of-the-art research contributing towards sustainability in rotational moulding. The scope of this review broadly assessed all areas of the process such as material development, process adaptations and development, modelling, simulation and contributions towards applications carving a more sustainable society. The PRISMA literature review method was adopted, finding that the majority of publications focus on material development, specifically on the use of waste, fillers, fibres and composites as a way to improve sustainability. Significant focus on biocomposites and natural fibres highlighted the strong research interest, while recyclate studies appeared to be less explored to date. Other research paths are process modification, modelling and simulation, motivated to increase energy efficiency, reduction in scrap and attempts to reduce cycle time with models. An emerging research interest in rotational moulding is the contribution towards the hydrogen economy, particularly type IV hydrogen vessels.

Hidden mysteries in ancient Egyptian paintings from the Theban Necropolis observed by in-situ XRF mapping.

The material study of ancient Egyptian paintings began with the advent of Egyptology during the 19th century. By the 1930s, a lot had already been sampled and described. The limited palette for example has been analysed from actual painted surfaces but also from pigments and painting tools retrieved on site. However, most of these studies took place in museums while the painted surfaces, preserved in funerary chapels and temples, remained somewhat estranged from this primary physical understanding. The artistic process has been also reconstructed, mainly from the information presented by unfinished monuments, showing surfaces at different stages of completion. A lot of this modern and theoretical reconstruction is, however, based on the usual archaeological guessing game that aims at filling the remaining blanks. Our interdisciplinary project has decided to experiment on-site with state-of-the-art portable analysis tools, avoiding any physical sampling, to see if our knowledge of the work of the ancient Egyptian painters and draughtsmen could be taken at a further stage, while based on physical quantification that could be seen as a stronger and more reliable foundation for a redefined scientific hypothesis. The use of XRF mapping has, for instance, been applied to a known case of correction by surface repaint, something that is supposedly rare in the ancient Egyptian formal artistic process, while another fully unexpected one was discovered during the analytic exploration of a royal representation. In both cases, the precise and readable imaging of the physical composition of the painted surface offers a renewed visual approach based of chemistry, that can be shared through a multi- and interdisciplinary approach. However, this also leads to a more complex description of pigment mixtures that could have multiple meanings, where the practical often leads towards the symbolic, and from there hopefully to a renewed definition of the use of colours in complex sets of ancient Egyptian representations. At this stage, though the progress in this on-site material assessment of ancient works of art definitely means astonishing progress, one humbly has to face the fact that these ancient treasures shall still retain part of their defining mysteries.

Beauty Revealed: Technical Analysis and Treatment of Zand and Qajar Oil Paintings

ABSTRACT The interiors of Zand and Qajar palaces were often decorated with idealized portraits meant to convey wealth and internationality through depiction of European goods, jewelry, and other social signifiers. Five figurative oil paintings dating from the late 1700s to early 1800s were analyzed non-destructively using x-radiography, infrared reflectography, and macro-area x-ray fluorescence spectroscopy. Selective microscopic sampling enabled pigment and binder identification using Raman and Fourier transform infrared spectroscopy and scanning electron microscopy coupled with energy dispersive x-ray spectroscopy. All paintings are oil on cotton canvas and utilize a limited palette that includes Prussian blue, orpiment, and vermillion. Four paintings contain copper alloy leaf used to simulate gold jewelry and textiles. Artisanship expertise varies and European influences, including perspective and shading, are unevenly incorporated; workshop involvement is suggested by differing qualities of rendering within a given work. One painting, Dancing Girl (1192 AH/1778 CE) by Muhammad Baqir, was fully treated to remove thick layers of discolored shellac varnish and overpaint that distorted the appearance of the work. This study provides insights into the painting materials and techniques of the late Zand and early Qajar period, and practical methodologies for their treatment and continued preservation.

Back in Black: getting beneath the haze on Adolph Gottlieb’s Thrust

Thrust (1959) is an iconic example of Adolph Gottlieb’s series of “Bursts” (1956-1974). The painting is grand in scale and consists of an aggressive thrash of black, gestural strokes beneath a crimson, haloed disc, on a white background. Gottlieb said that given the limited palette, his color choices were critical in conveying the emotional quality of his work. The appearance of Thrust was compromised when efflorescence became visible on the surface in 1981; the material presented as a subtle white haze that made the black appear gray. By 1996, the effect had become more pronounced, and the painting was taken off view. Recent curatorial interest in displaying the painting motivated an evaluation of its condition and of treatment options. This paper discusses the painting’s materials and techniques, the composition of the efflorescence as investigated by spectroscopic and chromatographic methods, and considerations given to its treatment.

Small Molecules as Modulators of Voltage-Gated Calcium Channels in Neurological Disorders: State of the Art and Perspectives.

Voltage-gated calcium channels (VGCCs) are widely expressed in the brain, heart and vessels, smooth and skeletal muscle, as well as in endocrine cells. VGCCs mediate gene transcription, synaptic and neuronal structural plasticity, muscle contraction, the release of hormones and neurotransmitters, and membrane excitability. Therefore, it is not surprising that VGCC dysfunction results in severe pathologies, such as cardiovascular conditions, neurological and psychiatric disorders, altered glycemic levels, and abnormal smooth muscle tone. The latest research findings and clinical evidence increasingly show the critical role played by VGCCs in autism spectrum disorders, Parkinson’s disease, drug addiction, pain, and epilepsy. These findings outline the importance of developing selective calcium channel inhibitors and modulators to treat such prevailing conditions of the central nervous system. Several small molecules inhibiting calcium channels are currently used in clinical practice to successfully treat pain and cardiovascular conditions. However, the limited palette of molecules available and the emerging extent of VGCC pathophysiology require the development of additional drugs targeting these channels. Here, we provide an overview of the role of calcium channels in neurological disorders and discuss possible strategies to generate novel therapeutics.

Combining stale seedbed with deep rice planting: a novel approach to herbicide resistance management?

AbstractWater seeding is a common cropping strategy in mechanized rice systems. Water seeding of rice can suppress grass weeds, but it can also encourage aquatic weeds and grass ecotypes that escape deep floodwater. In addition, water seeding prevents many cultural methods of weed control and limits available herbicides. Selection pressure from a limited palette of herbicides has resulted in widespread resistance in rice grown in California. This study examined a novel combination of drill seeding and a stale seedbed (“stale-drill”) as a means of using a nonselective herbicide to manage weeds before rice emergence. In 2016 and 2017, rice cultivar ‘M-206’ was drilled at a rate of 120 kg ha−1 to 1.3-cm, 2.5-cm, and 5.1-cm depths. Planting rice deeper than 1.3 cm delayed emergence by 3 to 4 d. A postplant-burndown (PPB) treatment of glyphosate at 870 g ha−1 was applied just prior to rice emergence. Treatment delays had mixed effects on weed control. PPB treatment was more effective at controlling Echinochloa spp. in 2017, reducing density by 30%, 48%, and 73% at 1.3-cm, 2.5-cm, and 5.1-cm seeding depths, respectively. The greatest overall weed control either year was found with applications of glyphosate + pendimethalin followed by penoxsulam + cyhalofop at 1.3-cm planting depth. Rice stand and yield components were more strongly affected by planting depth in 2017 than in 2016, possibly owing to cool weather immediately after seeding. Yields in 2017 were reduced in deeper plantings by up to 72%. Therefore, if the stale-drill method is implemented with higher-vigor cultivars or higher seeding rates, we see potential in this method as a useful tool for reducing herbicide-resistant weeds in rice fields.

METHODOLOGICAL AND TECHNICAL ENVIRONMENT OF WATERCOLOR PAINTING FOR STUDENTS-ARCHITECTORS

The article considers that watercolor technique is the most advanced one for the transfer of living architectural forms of structures in the drawing. Drawings of architectural projects should give a full understanding of the correct purpose, about the cost-effectiveness, strength and beauty of the future building. Therefore, drawings must be clear, understandable, expressive, their graphic performance must be based on the high foundations of realistic art. Watercolor is a professional and traditional visual means of an architect. Watercolor is an amazing material that combines the ability to comprehend both the pictorial, color organization of the image and the graphic, sign-tonal one. The architect, referring to the picturesque development of the drawing, first of all, must determine its purpose and choose from all the numerous visual techniques of watercolor painting those that will better contribute to the expressiveness of this drawing. Then they will be correctly used: the perfect visual equipment, a large arsenal of tools, a wide range of techniques, a large palette of colors, various possibilities of tools and materials. These features allow you to cope with multitasking in a wide variety of visual arts. The main features of watercolor painting are high airiness and transparency. However, architectural watercolor has its own specific conventions, some generalization, laconicism, business simplicity, clarity, a certain limited palette of colors, but at the same time it successfully fulfills its task only when it proceeds from the position of realistic painting.Such watercolor techniques as: “wet”, “dry”, “glaze”, “ά la prima” are considered The technique of watercolor painting is a visual reflection of the main theoretical postulates of the composite space organization on the plane. Watercolor techniques solve these problems and clearly show the interaction of tonal and color characteristics of all elements of the composition.

Ornamental motives in the modern packing products of Ukraine

The purpose of the article. The research analyzes the transformations of traditional Ukrainian ornamental motifs and decorative and symbolic images in relation to their use in the design of modern packaging products; It was observed that the appeal of designers to established ornamental forms and decorative-symbolic images gives expressiveness to graphic solutions in the design of the packaging. The article emphasizes the possibility of using the established ornamental motifs in the contemporary design activity of graphic designers for qualitative design-development only if the project activity combines a creative approach based on thorough research on the background of an extremely limited palette and surface-already-existing work of ornamental heritage. The methodology of the study is to apply a systematic approach that helps to reveal the peculiarities of the use of ornamental motifs in the packaging of goods in different consumer segments. The scientific novelty consists in determining the necessity of combining creative and scientific approaches for careful/careful adaptation or adaptation of traditional Ukrainian ornamentation in the design of packaging products; in shaping the latest / renewed vision of not only established ornamental motifs but also bold, unexpected decisions and creative transformations filled with new content. Conclusions. Based on the analysis of samples of packaging products in the design of which we use ornamental motifs and decorative and symbolic images, we have come to the conclusion that modern revisions of graphic designers demonstrate not only the commitment to direct application of authentic ornamental motifs and the use of already well-established and acquaintance consumers of motifs from Ukrainian ornamentation, and application in practical developments of unexpected decisions and transformation, which in turn adds not only an update to the perception of traditional orn entalno and decorative solutions, but also to attract yet untapped segment of consumers. Thanks to the popularization of Ukrainian ornament with the help of packaging design, graphic design projects also play the role of researcher and educator for a wide range of consumers of packaged goods in different consumer segments.

Orange & Teal

Abstract ‘Orange & Teal’ has become the preferred ‘look’ of the Hollywood movie industry. Is this craze just another arbitrary fashion? Possibly not, because ‒ apart from the name ‒ this palette has been around for ages in the visual arts. It is variously known as ‘painting in cool and warm,’ drawing a trois croyons, use of a ‘limited palette,’ and so forth. This leaves open the question of whether there might be one or more fundamental reasons for the preference for this particular dichromatic pair. Why not yellow–blue, red–turquoise, or green–purple? Reasons might be sought in human anatomy/physiology, physics of surface scattering, or the ecology of the human Umwelt. An in-depth analysis reveals that all these factors cooperate to render the orange & teal complementary palette indeed special. It involves world, body and mind and has to be understood in a proper semiotical (biological) setting.

Seeding depth effects on elongation, emergence, and early development of California rice cultivars

AbstractThe continuous use of a water‐seeded cropping system for California rice (Oryza sativa L.), along with a limited palette of available herbicides, have selected for flood‐tolerant grasses, aquatic species, and herbicide‐resistant weed populations throughout the region. Alternative cropping methods such as stale‐seedbed and deeper drill seeding may be combined to allow novel herbicide modes of action and combat resistance while providing economically competitive yields. Two experiments were conducted to evaluate rice cultivars for vigorous traits that would facilitate such a stale‐drill cropping methodology. Four cultivars of California rice were grown in glasshouses and evaluated for differences in germination, elongation, emergence, and early season morphology. Cultivars M‐205 and M‐209 were found to have greater rates of total below‐soil elongation, and greater rates of mesocotyl and coleoptile elongation overall, across depths. M‐205 and M‐209 were also found to have higher rates of emergence across depths. Differences in aboveground growth parameters of emerged seedlings were only found at 0‐, 6.4‐, and 7.6‐cm planting depths. Based on observed below‐ and above‐soil growth and development, M‐205 and M‐209 exhibited greater vigor overall, as well as high levels of emergence from depths greater than 2 cm. Therefore, these cultivars should be suitable for stale‐drill seeding as a strategy for managing herbicide resistance in California.

Appropriating Indo-Saracenic style: Bhai Ram Singh’s contributions to the architectural identity of 19th century Lahore

After 1857, when India became a direct colony of the British Crown, was the architectural style adopted by the colonial masters an attempt at subverting the local identity and reasserting their supremacy via architecture or was its purpose to engage their institutions with their context? Was the Indo-Saracenic style of architecture anachronistic and reductive in nature or was it a way to draw on the past? What role did the Jeypore Portfolio play in negotiating colonial intent by appropriating traditional building culture? How did Bhai Ram Singh mediate an identity for 19th century Lahore by contextualizing Indo-Saracenic architecture? This exploratory study attempts to answer these questions using existing literary sources and by considering buildings designed by Bhai Ram Singh in the city of Lahore. The paper also critically evaluates the agency of the Jeypore Portfolio for Indo-Saracenic architecture, how it reduced the centuries-old local building tradition to a limited palette of details, and Bhai Ram Singh’s attempts to re-inform it from the native’s perspective.

Colour Trans:Form:Ation the Application of Knit as Knowledge

It is widely acknowledged that textile processing is increasingly unsustainable, for example textile dyeing is experiencing a rising use of water. It is imperative to investigate alternative strategies to colouration and whilst there is no single resolution to the problem, using design intelligence from diverse design specialisms, in this instance knitted fabric design, can offer a realistic framework within which to develop solutions.Following established design methodologies, successful knit design requires knowledge of materials, process, technology and aesthetics which is utilised in unique combinations to create a specified product. Disrupting this approach to design through the application of innovative technologies or removing the concept of designing for a specified product, this unique body of knowledge can question wider societal problems, including textile coloration, and determine a range of solutions through knitted fabric design practice.The paper will report on the development of sustainable textile coloration through innovative lighting technologies. New research explores the breadth of colour gamut achievable with a limited palette of yarn (so minimising dyeing) when recognised optical effects, for example optical mixing, are observed in different lighting conditions. The iterative design/research methodology used exploits the materiality and structural knowledge inherent in knitted fabrics and allows the creation of unique fabrics, which would be unachievable in any other medium, to test ideas abductively. A feature of this methodology is an acceptance of unexpected outcomes that challenge the concept of designing for a specified product. The fabrics produced are not in themselves functional, except as a communication tool for the knowledge revealed through the design research.

Mapping the pigment distribution of Vermeer\u2019s Girl with a Pearl Earring

As part of the 2018 Girl in the Spotlight project, reflectance and molecular fluorescence imaging spectroscopy (RIS, FIS), and macroscale X-ray fluorescence scanning (MA-XRF) were performed on Johannes Vermeer’s Girl with a Pearl Earring (c. 1665, Mauritshuis) with the goal of obtaining a comprehensive understanding of the distribution of pigments. Prior analysis of cross-sections in the 1990s, and their recent (re)-examination identified many of the pigments present in the painting. The results from all three imaging methods, along with site-specific fibre optic reflectance spectroscopy, confirmed Vermeer’s limited palette and determined how and where each pigment was used. RIS and MA-XRF found the blue region of the headscarf was painted with natural ultramarine and varying amounts of lead white. The yellow part of the headscarf was painted with yellow ochre and lead white, and the border of the headscarf additionally contained ultramarine and lead–tin yellow. The lit side of the jacket was painted with yellow ochre, lead white, and ultramarine, whereas the darker, ruddy blue-green areas that are in relative shadow contained yellow ochre with ultramarine. FIS also mapped a red lake in portions of the shadowed areas at the back of the jacket. The Girl’s skin was painted using earths (ochres), lead white, vermilion, and some red lake. Fluorescence emission from red lake was strongest in the lips, where vermilion was also found. The pearl earring was depicted using a scumble and highlight of lead white. In the dark background, the RIS data cube allowed the determination of the visible spectral shape even though the overall reflectance intensity was low (1 to 3%). A reflectance inflection point at ~ 700 nm indicated the presence of indigo, whereas lack of a reflectance peak at green wavelengths in most areas indicated degradation of the yellow pigment previously identified as weld. Some small green areas in the background (i.e. reflectance maximum at 525 nm) were found; these coincided with areas previously protected by old retouchings, and are thus better preserved. The combination of all three spectral imaging modalities provided a more complete understanding of how the colouration of the painting was achieved.

The search for Cezannism in the prac-tice of Adalbert Erdeli of 1930–1940.

The search for Cezannism in the prac-tice of Adalbert Erdeli of 1930–1940.

Practical aspects of colour science in the educational process. Using a limited palette

The paper presents the practical aspects of colour science in the context of the interaction of colours and obtaining certain shades. As a practical teaching methodology, the use of a limited palette of three primary colours in several modifications has been offered. The given individual author's observations and conclusions formed in the process of teaching painting in the higher art school. The paper presents some of the author's observations and conclusions emerged in the process of teaching painting in a higher art school. A practical problem is the shallow knowledge of the physical features of colour, the standardization of the educational palette, the absence of an individual artist's palette. To avoid those problems, the students were asked to use a limited palette instead of the standard one. It is based on three primary colours in different versions. For each task, two options of a basic paints set were offered with the condition that other ready-mixed paints would not be used. The painting task prompted the creation of a wide scale of cold and warm colour tones. Relying on the colour theory, the students had to create their own palette of complementary colours (purple, orange, green), as well as their shades. In the course of work, it turned out that the very fact of the finished palette absence was the most difficult for the students. The first attempts to mix the main colours took a lot of time, but at this stage they began to be more attentive to the properties of paints, to notice the difference in shades, to vary the saturation of colour. Almost all the students have achieved the effect of a wide range of ochre and brown colours and have created a fairly wide palette. The resulting colours have turned out to be easy to reproduce and convenient to use. The results of the work prove that practical tasks with a limited palette use are informative and useful in teaching painting. An empirical research of the interaction of pigments will help students to learn and successfully embody their own painting intentions.

How to Walk an Ant by Cindy Derby

Reviewed by: How to Walk an Ant by Cindy Derby Deborah Stevenson, Editor Derby, Cindy How to Walk an Ant; illus. by Cindy Derby. Roaring Brook, 2019 [40p] ISBN 978-1-250-16262-5 $17.99 Reviewed from galleys R 5-8 yrs Amariyah is an “Expert Walker,” her specialty is ants, and she’s kind enough to share her expertise in her “very own nine-step guide.” The steps range from “Politely Introduce Yourself” to “Prepare the Leash” to “Make a Goal” (in this case, walking to an ice cream truck) to the daunting Step Eight: “When you encounter a colony of ants repeat steps two through seven three thousand and twenty-eight times.” Then Amariyah’s many, many leashes get tangled up with the leashes of another girl out walking ladybugs, and after disentangling (and mourning the casualties—an appendix offers a guide to ant funerals) the girls bond over ice cream. The confident guide format is funny, and the contrast of our heroine’s assured manner with the fanciful details and chaotic outcome ramps up the comedy. It’s the art that kicks this through the goalposts, though; Derby’s watercolors, in a limited palette where black and gray predominate, have the fierce childlike disorder of Neal Layton with a touch of Stephen Gammell in the squirrely lines. Soft gray washes background wild-haired Amariyah, the precisely inked ants, and the trickly, hand-lettered-style text and speech emanata. The result is both edgy and cute, reveling in and amplifying the story’s enjoyable weirdness. Kids who’ve had enough of picture-book bunnies will welcome the originality here, and ant lovers who can get past the fatalities will appreciate the ant information scattered throughout and in a second appendix. [End Page 293] Copyright © 2019 The Board of Trustees of the University of Illinois

Earth Verse: Haiku from the Ground Up by Sally M. Walker

Reviewed by: Earth Verse: Haiku from the Ground Up by Sally M. Walker Deborah Stevenson, Editor Walker, Sally M. Earth Verse: Haiku from the Ground Up; illus. by William Grill. Candlewick, 2018 [48p] ISBN 978-0-7636-7512-7 $17.99 Reviewed from galleys Ad Gr. 3-6 The noted nonfiction writer turns from prose to poetry here in nearly thirty haiku about the planet Earth. Topics are divided into eight categories, such as rocks ("Molten magma stew/ bubbles out of its hot pot"), earthquakes ("energy unleashed"), and surface water ("sediment-filled waves/ tumble in a frothy foam"). While there"s an ironic contrast between the massiveness of the subject and the petite precision of the verse, there are some dramatic snapshot moments of earth processes and pleasing imagery ("a gull wears sand socks"). The visuals are less successful, however; Grill employs a limited palette of red, blue, and black, with most images only employing two colors, in soft, blurry colored pencil that results too often in confusingly amorphous images. Additionally, the thumbnail legends indicating which category each poem fits into aren"t clear on their own and are only explained in the extensive end matter, which also gives some contextual information about the more challenging scientific vocabulary. The verses could still pique the interest of young scientists, though, and offer some of the curricular opportunities for earth science that Joyce Sidman does for biology. Suggestions for further reading are appended. Copyright © 2018 The Board of Trustees of the University of Illinois

Identifying eighteenth century pigments at the Bodleian library using in situ Raman spectroscopy, XRF and hyperspectral imaging

There are multiple challenges in analysing pigments in historic watercolour paintings on paper, and typically non-invasive, in situ methods are required. Recent developments in portable analytical instrumentation have made this more accessible to heritage institutions, but many commercial systems are not optimised for the specific requirements of manuscripts and works on paper. This paper describes the successful use of Raman spectroscopy, X-ray fluorescence spectroscopy (XRF) and hyperspectral imaging to identify and map watercolour pigments used by the eighteenth century botanical illustrator, Ferdinand Bauer, and demystify the unusual colour code system found in his sketches. The value, delicate nature and large size of these paintings necessitated the use of using in situ, non-contact methods of analysis. A portable, bespoke Raman spectrometer specifically designed for analysing pigments from works on paper was used together with a bespoke portable Fibre optic reflectance spectrometer, portable X-Ray Fluorescence spectrometer and a hyperspectral imaging sensor. The results demonstrate that although there is a significant compromise between achieving good Raman spectroscopic results from artists’ pigments and using sufficiently low laser power densities so as not to cause damage to the pigments, good results could be obtained with this portable system, particularly when combined with XRF, fibre optic reflectance spectroscopy (FORS) and hyperspectral imaging. Eight pigments were identified unequivocally from 125 watercolour paintings analysed, suggesting that Bauer used a more traditional and more limited palette than previously considered, and that his palette changed significantly in his later paintings. Similar pigments identified by the authors on colour chart that was discovered in 1999 in Madrid and attributed to Bauer, add weight to the attribution of this chart to Bauer. The data provides a much deeper insight into Bauer’s colour annotations, and how he was able to achieve such an impressive degree of colour fidelity in his work.