Raking Light Research Articles

Using 3D scanning to support conservation treatments for paintings

Various imaging techniques are used to visualise issues regarding a painting’s appearance before, during and after conservation treatments, i.e. visible light photography (VIS) raking light photography (RAK), ultraviolet fluorescence photography (UVF) and reflectance transformation imaging (RTI). However, these techniques cannot always visualise and/or quantify conservation issues. This paper presents a new approach: colour, gloss, topography imaging (CGT). CGT’s applicability as a non-invasive tool for evaluating and documenting conservation treatments in comparison to VIS, UVF, RAK and RTI is discussed. Applying this to case studies with different conservation dilemmas illustrates the technique’s potential and drawbacks. CGT can visualise issues such as gloss variations, resulting from (previous) cleaning tests, (partial) varnish removal, and possibly dirt and material degradation. Furthermore, CGT can elucidate topographical issues such as bulging, and losses, and also visualise high-frequency surface variations (e.g. canvas weave and crack pattern). This results in an improvement of documenting a painting’s condition, and the evaluation of treatments and their effects on the visual appearance may be quantified. In conclusion, this research shows that CGT is able to better visualise texture, gloss and colour information than existing techniques like technical photography, facilitating a more precise documentation and localisation of previous and current conservation treatments.

Time and memory in Carthage

AbstractRome and the Roman idea of imperium – a centring, totalizing military and legal right to rule and command obedience – looms large behind innumerable historical instances of geopolitical aspiration. Yet the story of ancient Rome and the empire it shaped does not belong to Rome alone. From the very beginning, and throughout its history, it was linked repeatedly and inextricably to a peripheral alter‐ego: Carthage, established in present‐day Tunisia by Phoenicians settlers from Tyre. Much has been written about the historiographical representation of the conflicts between the two cities. The focus of ‘Time and Memory in Carthage’ is instead on the city's spatial and memorial presence, and on the raking light it throws across the narrative of empire that European tradition inherited from Rome. Using a range of material from Virgil's Aeneid to medieval and Renaissance visual depictions of Carthage, this essay attends to the strange tricks that the city of Carthage plays with both time and space, both in the Roman imagination, and in the early modern world – opening up spaces of conversation and alterity that survived even as the city's architectural space was destroyed, reappropriated, rebuilt, and reimagined.

Analysis of Middle Nubian Vessel-forming Technology Using Reflectance Transformation Imaging (RTI)

Reflectance Transformation Imaging (RTI) is a photographic technique used to generate digital surrogates of surfaces that can be viewed using virtual lighting coming from interactively set directions, enabling the close structural examination of objects under digital raking light. In this study, RTI was applied to Middle Nubian pottery from sites near the Second Nile Cataract that were excavated by the Scandinavian Joint Expedition to Sudanese Nubia in the early 1960s. The ceramic traditions under investigation are currently known as C-Group, Pan-Grave and Kerma. An overarching aim of the project is to assess the possibility of understanding the relationships between these groups through detailed analyses of their material traditions. Based on the hypothesis that technological traditions may be related to cultural heritage, RTI is applied in this study to observe morphological traces of ceramic vessel forming processes. Two technological groups were identified, one consistent with paddle-forming, and another consistent with hand-building on a mat-lined surface. These technological groups correspond very closely to cemetery distributions, which suggests that the different techniques may be specific to different potterymaking traditions. It is suggested that vessel forming-technology in the so-called C-Group tradition is distinct from that of the so-called Pan-Grave and Kerma traditions, and that the validity of the divisions between Nubian cultural groups should thus be further interrogated.

Measuring parameters of canvas texture from images of paintings obtained in raking light

In this work, the problem of threads counting in images of canvases of paintings is considered. Counting of threads is necessary for measuring canvas density and a number of other parameters used by art historians for dating the artworks. We propose to use raking light in the image acquisition process in order to emphasize canvas texture. We modify and adapt known techniques developed for inspecting fabrics in the textile industry. Three threads counting algorithms based on filtering in the Fourier domain and thresholding techniques are proposed and tested. These algorithms for measuring the canvas density from images taken in raking light are efficient in cases when lead white has been used to create the painting, and the analysis of canvas images acquired in X-rays and transmitted light is ineffective. The results of the experiment show that the accuracy of the proposed threads counting algorithms is comparable to the accuracy of known techniques.

Judith and Holofernes: Reconstructing the History of a Painting Attributed to Artemisia Gentileschi

Recently, a new painting attributed to Artemisia Gentileschi was found in Ferrara, representing Judith exposing the head of Holofernes. Some analyses have been required to verify the history of this canvas, because another known painting is very similar to this one with the exception of the heads of Judith and Holofernes. This last has been attributed to the father of Artemisia, Orazio Gentileschi. Many diagnostics were performed, starting from imaging techniques: from raking light, to UV fluorescence and X-ray radiography. All of them highlighted peculiarities concerning above all the head of the main female protagonist. The results suggest that the face of Judith was subjected to various reworks in the same artistic period because of the original materials still present. This is the reason for the peculiar fragility and, due to this, the restoration of the 20th Century focused on Judith’s face. However, in this contribution, we want to highlight the results obtained with XRF spot analysis. Indeed, the artistic palette and the restoration materials have been characterized. For example, reds are in cinnabar, while Judith’s lips have been restored with cadmium red. The more interesting results regard the use of umber earths. In the painting, this iron-based pigment, rich in manganese, was revealed several times, and the correlation between Fe and Mn was easily verified. More than one correlation has been found due to the use of this pigment to darken the hues.

PURSUING AUTOMATED CLASSIFICATION OF HISTORIC PHOTOGRAPHIC PAPERS FROM RAKING LIGHT IMAGES

Surface texture is a critical feature in the manufacture, marketing, and use of photographic paper. Raking light reveals texture through a stark rendering of highlights and shadows. Though close-up raking light images effectively document surface features of photographic paper, the sheer number and diversity of textures used for historic papers prohibits efficient visual classification. This work provides evidence that automatic, computer-based classification of texture documented with raking light is feasible by demonstrating an encouraging degree of success sorting a set of 120 images made from samples of historic silver gelatin paper. Using this dataset, four university teams applied different image-processing strategies for automatic feature extraction and degree of similarity quantification. All four approaches successfully detected strong affinities and outliers built into the dataset. The creation and deployment of the algorithms was carried out by the teams without prior knowledge of the distributions of similarities and outliers. These results indicate that automatic classification of silver gelatin photographic paper based on close-up texture images is feasible and should be pursued. To encourage the development of other classification schemes, the 120-sample “training” dataset used in this work is available to other academic researchers at http://www.PaperTextureID.org.

SWIRL, a clinically validated, objective, and quantitative method for facial wrinkle assessment

Facial wrinkles are an undesirable feature caused by extrinsic photodamage and intrinsic aging process. Many cosmetic products and esthetic procedures strive to ameliorate the appearance of wrinkles. Currently the effects of those products and procedures on wrinkles are mainly evaluated by clinical grading, subjective self-assessment questionnaires, and optical profilometry of replica impressions. An objective and quantitative method is in demand. Raking light optical profilometry was applied directly to facial photography to cast wrinkles as dark shadows. The resulting high-resolution digital images were analyzed using Image Pro software. A high-throughput method, Stephens Wrinkle Imaging using Raking Light (SWIRL), was developed to analyze the severity of wrinkles using photographs taken under the raking light condition. This method was applied to photographs taken from many panelists with a wide range of wrinkle severity scores. The result was compared with clinical grading scores to determine its validity. In addition, this method was applied to photographs taken from panelists before and after product usage to determine its sensitivity. Using the SWIRL method, multiple wrinkle parameters were quantitatively assessed, including wrinkle count, length, width, area, and relative depth. Those parameters correlated well with clinical grading scores, showing correlation coefficient (r value) of about 0.8 for all parameters. This result indicates that the SWIRL method is a valid method for analyzing wrinkle severity. When applied to a clinical study, the SWIRL method was sensitive enough to detect improvement after 8 weeks of product application. The SWIRL method has been fully validated through clinical studies. It is accurate, objective, and quantitative. As multiple wrinkle parameters are analyzed simultaneously, it can provide more detailed information on how wrinkles change over time and therefore has the potential to shed light on the action and mechanism of antiwrinkle products.

Efficacy of a Novel Treatment Serum in the Improvement of Photodamaged Skin

SynopsisA novel treatment serum formulated to target multiple pathways in the anti-ageing cascade was tested both in vitro and in clinical settings. In vitro testing was performed to assess the ability to stimulate key proteins and genes fundamental to the anti-ageing cascade. The antioxidant potential of the formulation was studied in a UV-irradiation clinical study. A 12-week, open-label, single-centre study was conducted to determine whether this uniquely formulated topical treatment serum could improve visible signs of facial photodamage. Clinical evaluations showed statistically significant reductions in fine wrinkles and coarse wrinkles and improvements in skin texture, tone and radiance starting at week 4 with continued improvements at weeks 8 and 12. Subject self-assessments confirmed that the beneficial effects of the treatment serum were readily observed by the users. The treatment serum was well tolerated with no treatment-related adverse events reported during the 12-week study. Use of this novel treatment serum produced significant improvements in the visible signs of facial photodamage.RésuméUn nouveau sérum de traitement conçu pour cibler de multiples voies dans la cascade anti-âge a été testé à la fois in vitro et dans les conditions cliniques. Les tests in vitro ont été réalisés afin d'évaluer la capacité de stimuler les protéines et les gènes clés fondamentales de la cascade anti-vieillissement. Le potentiel antioxydant de la formulation a été étudié dans une étude clinique utilisant le rayonnement UV. Une étude de douze semaines, en mode ouvert, monocentrique a été menée afin de déterminer si ce sérum spécialement formulé pour le traitement topique peut améliorer les signes visibles du photo-vieillissement du visage. Des évaluations cliniques ont montré une réduction statistiquement significative des rides et des ridules secondaires et l'amélioration de la texture de la peau, du tonus et d'éclat à partir de la semaine 4 avec des améliorations continues aux semaines 8 et 12. Les autoévaluations par les sujets ont confirmé que les effets bénéfiques du sérum de traitement étaient facilement observés par les utilisateurs. Le sérum de traitement a été bien toléré avec aucun événement indésirable rapporté au cours de l'étude de 12 semaines. L'utilisation de ce nouveau sérum de traitement produit des améliorations significatives dans les signes visibles du photovieillissement du visage.

Blake's Heavy Metal: The History, Weight, Uses, Cost, and Makers of His Copper Plates

Blake's Heavy Metal1 The History, Weight, Uses, Cost, and Makers of His Copper Plates G. E. Bentley, Jr Professor Emeritus, Department of English, University of Toronto 'Here alone I in books formd of metals Have written the secrets of wisdom' Urizen pl 4, ll 69–702 For Blake's work in designing and engraving, we know a good deal about the surface on which he worked. Usually, of course, it was paper, whether the record3 is explicit or implicit. For the graphic works, sometimes Butlin specified not only 'paper' but grey paper (no. 572), 'yellowish paper' (no. 634), 'Tracing paper' (no. 646, 754, 856), 'tracing-like paper' (no. 408), 'buff cartridge paper' (no. 254), 'prepared paper' (no. 407), card (no. 347 [miniature of Johnny Johnson], 635), and 'common thick mill-board' or 'pasteboard' (according to his disciple Frederick Tatham) for the Large Colour Prints (no. 289–329).4 For his drawings Blake also used Canvas,5 'Fine linen' (no. 667–68), Muslin (no. 811), Ivory (no. 376–78, miniatures of Thomas Butts, his wife, and son), Glass (Felpham Rummer [1803], not in Butlin), Panel (no. 750 ['Ghost of a Flea'], 810), Pine (no. 808–9), Mahogany (no. 674, 806–7), and a Wood-block (no. 773). [End Page 714] But for present purposes, the most interesting material is metal.6 It was of course copper on which Blake usually made his engravings and etchings. Scores of these pieces of copper survived Blake's death in 1827, and about 1831 Tatham printed Songs of Innocence and of Experience, America, Europe, For the Sexes: The Gates of Paradise, and Jerusalem. However, Tatham managed to lose most of the copper plates. The only surviving piece of copper <Illustration 10a> from Blake's works in Illuminated Printing is part of the abandoned version of America (1793) pl a <Illustration 1>. Copper was enormously important to Blake; as he himself wrote, 'Mr B ... during a Period of forty Years never suspended his Labours on Copper for a single day.'7 His own works in Illuminated Printing were etched on copper, and he might have written of them what Urizen says of his universal creation: 'Here alone I in books formd of metals Have written the secrets of wisdom' (Urizen pl 4, ll 69–70) In letterpress printing, one pass through the press prints several pages – four pages per side in a quarto, twelve pages in a duodecimo, &c. But in printing from an engraving in a rolling press <Illustration 3>, a single pass through the press normally produces only a single image. The copper plate had to be cleaned, re-inked, and printed twelve times to produce twelve copies of the image.8 The pressure of the roller on the dampened paper was so heavy that the engraved image was slightly embossed on the paper. Even when the ink was wiped off the plate, the obscured portions can sometimes be detected in a raking light; in The Marriage of Heaven and Hell (copy M) the 'Chorus' of 'A Song of Liberty' was not inked, but embossed portions of it may still be seen.9 Text and engravings were printed in separate shops, sometimes at considerable distance and inconvenience. For Hayley's Designs to a Series of Ballads (1802), Seagrave in Chichester printed the text and sent it to Blake [End Page 715] Click for larger view Illustration 1 America (1793) pl a [Library of Congress] (16.1 x 22.8 cm), an alternative to pl. 5. It was kept by Blake for more than ten years and carried to Felpham (1800) and back to London (1803) – copper was valuable and money was scarce in the Blake household – until eventually it was cut up about 1805 [Illustrations 10a, b, c] to be used for apprentice engravings by Blake's student Thomas Butts. [End Page 716] in Felpham to add the prints, collate text and prints, stitch in wrappers, and...

Microscopes in Art Galleries?

Abstract In addition to concerns about the appearance of a display, curators of art galleries are also concerned about conservation of the artwork and their authenticity. Microscopes have played a role in these latter activities since the 1930s. Various imaging techniques, including X-radiography, infrared reflectography, macrophotography, UV-fluorescence and raking light (light source at a low angle to the surface) imaging have their advantages and disadvantages. Confocal microscopy is most useful compared to the other methods for the purpose of examination of subsurface structure, but the close working distance (a few mm) makes it precarious to use on valuable masterpieces. More recently, Haida Liang, Marta Cid, Radu Cucu, George Dobre, Adrian Podoleanu, Justin Pedro, and David Sauders have demonstrated the usefulness of optical coherence tomography (OCT) for non-destructive examination of artwork. OCT, as discussed previously in this column, is more commonly used to examine biological specimens.

Writing the Meal: Dinner in the Fiction of Early Twentieth-Century Writers by Diane McGee

REVIEWS Deconstructive readings of decadent texts throw a raking light over continual alterations of signification, the “perennial decay,” referred to in the book’s title: “Decadent textual strate­ gies interfere with the boundaries and borders (national, sexual, definitional, historical, to name but a few) that criticism nor­ mally relies upon to make its judgments, producing what we call a ‘perennial decay’ of those boundaries and borders” (11). This position implies that theory, at least in the form of decon­ struction, is likewise a mode of “perennial decay,” indeed, of decadence. In refraining from directing its attention backward (so to speak) upon its own theoretical premises and methods, Perennial Decay chooses not to name deconstruction itself as one of the latest and most potent articulations of Decadence, a truth that, from the mouths of academic humanists, has fre­ quently been hurled in the form of an accusation against deconstruction . Within the context of a volume such as this one, deconstruction needs to come out as decadent, even if doing so prevents it (and us) from ever safely exiting the purlieus of Decadence. Within this general set of parameters, readers with an inter­ est in literary and other modes of decadence will find a variety of items of interest in this collection: an essay on opera and disease by Marc A. Weiner; the art of posing in Latin American liter­ ature of the fin de siècle (Sylvia Molloy), and the connection between Dorian’s portrait and late Victorian and Edwardian portraiture practice (Dennis Denisoff). RICHARD DELLAMORA / Trent University Diane McGee. Writing the Meal: Dinner in the Fiction of Early Twentieth-Century Writers. Toronto: University of Toronto Press, 2001. 221. $60.00 cloth. Re-imagine Michelangelo’s Creation of Adam: instead of the masculine text of a finger-tip touch through which God dele­ gates authority to a lolling Adam, picture instead God’s ex­ tended arm in the act of handing over to a harried Eve the divine cooking pot so that she can assume responsibility for 539 ESC 28, 2002 whipping up mini-acts of Creation daily in order to re-vivify physically and spiritually all those gathered round the hearth for the dinner rites. A vision only slightly less ambitious is set up at the beginning of McGee’s study. The first chapter draws upon a variety of anthropological and sociological references to argue that meal preparation is not only a cultural text but also a site of origins: “Thus the roots of storytelling, art, and religion are linked to cooking,” and “Through this process of ordering and transforming the world, cooking can be viewed as the ba­ sis of thought” (13). Not only are food preparation practices “conveyers of meaning both to those within the group and to outsiders” (11), but also, “in that they create meaning, these activities are fundamental to thought and to language” (13). Before narrowing her scope to meals of various sorts (pri­ marily dinners because they are the most ritualized), McGee provides an overview of changing societal attitudes towards cooking and women’s domestic roles in the late nineteenth and early twentieth centuries. She thus establishes a historical con­ text for the argument to turn from the notion of origins to the specific time-frame of modernity. The dinner analyses that fol­ low are situated to be reflective of problems rooted not just in women’s social roles but also in western culture’s worried responses to a changing world. McGee’s approach to dinner as discourse concentrates on female characters acting in the broadly defined roles of host­ ess or guest in fiction by Edith Wharton, Katherine Mansfield, Virginia Woolf, and Kate Chopin (with the work of some other women writers mentioned in passing, along with that of an occa­ sional male author). Interactions of gender, class, and economics are convincingly examined in novels by Wharton, and Clarissa’s significance as hostess in Woolf’s Mrs. Dalloway gets a more sympathetic reading than is often the case. The chapters on Mansfield may be especially welcome to readers because, despite the steady growth in Mansfield studies over the last few years, there are fresh insights here. To close, McGee picks up on her...

Response to “What Knowledge is Most Worth Knowing?”

Jim Bell and Pam Flagel's fascinating case study, “What Knowledge Is Most Worth Knowing? Grammar, Critical Thinking, and Revision in Writing Conferences,” casts a raking light over some of our most cherished beliefs about peer tutoring. I say “casts light” rather than “sheds light” because the case puts me in a scrutinizing frame of mind rather than reassuring me that I have achieved enlightenment. Sometimes Bell and Flagel's study shows that our beliefs pull us in opposite directions, recommending contradictory exclusive paths of action. At other times the study suggests our beliefs need some qualification, or at least tweaking, if they are to serve as effective tutoring guidelines. In my response, I would like to examine several ways in which the study has challenged me to think more deeply about these beliefs.

Following Seamus Heaney’s “Follower”: Toward a Performative Criticism

Research Article| September 01 2000 Following Seamus Heaney’s “Follower”: Toward a Performative Criticism John Boly John Boly Search for other works by this author on: This Site Google Twentieth-Century Literature (2000) 46 (3): 269–284. https://doi.org/10.1215/0041462X-2000-4006 Cite Icon Cite Share Icon Share Twitter Permissions Search Site Citation John Boly; Following Seamus Heaney’s “Follower”: Toward a Performative Criticism. Twentieth-Century Literature 1 September 2000; 46 (3): 269–284. doi: https://doi.org/10.1215/0041462X-2000-4006 Download citation file: Zotero Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search Books & JournalsAll JournalsTwentieth-Century Literature Search Advanced Search The text of this article is only available as a PDF. Copyright © Hofstra University2001 Article PDF first page preview Close Modal Issue Section: Articles You do not currently have access to this content.

Imaging incised documents

Wooden stilus tablets and lead curse tablets from the Roman empire are among the most difficult ancient documents to decipher: the former because they often preserve traces of incised writing from more than one text on a surface characterised by wood-grain and casual damage; the latter because the scratched letters, once bright and shining, have long since oxidized so that they have the same colour as their background, grey on grey, greatly reducing image contrast. Like the stilus tablet scratches, the writing on a curse tablet is only visible under intense, low raking light, which needs frequent adjustment. This paper describes the initiation of a project to develop a new programme of stereoscopic, three-dimensional image enhancement in order to make these texts visible and legible

Rock Painting and Petroglyph Recording Projects in Canada

Rock paintings, pictographs, and petroglyphs are vulnerable to natural weathering and threatened by vandalism. Photography can provide accurate records of rock art sites for posterity, interpretation, and research. Photographic methods for red ocher rock paintings in the Canadian shield were investigated, including infrared photography, infrared luminescence, and false-color infrared; ultraviolet reflected and fluorescence photography; and cross-polarization using electronic flash. High contrast copy film with a blue filter was found to be useful. Camera stability, color temperature, film format, and exposure and color reproduction controls are discussed. Digital image processing was found to be applicable to the enhancement of photographic images of rock paintings. The photographic and photogrammetric recording of three sites from the frozen surface of the Churchill River is described. Methods for recording petroglyphs are reviewed. These have included tracing, rubbing, molding, and casting. Electronic flash raking light photography at night and stereophotogrammetry were undertaken at a petroglyph site in marble in Ontario. Machine vision systems, for example, laser scanners, could eventually find application in petroglyph recording and replication. The article includes a comprehensive bibliography of rock art recording methods.