Appearance Of Paintings Research Articles

A mass spectrometry and electron paramagnetic resonance study of photochemical and thermal aging of triterpenoid varnishes.

Photochemical and thermal aging of triterpenoid dammar and mastic resins used as varnishes on paintings were studied using graphite-assisted laser desorption/ionization mass spectrometry. This extends an earlier study on similar materials (Zumbühl et al., Anal. Chem. 1998, 70, 707-715) that focused on photoaging. Progressive aging results in development of groups of signals spaced by 14 and 16 Da, indicating incorporation of oxygen as well as simultaneous loss of hydrogen. Oligomers up to tetramers are formed, while cleavage reactions lead to increased signal intensities in the mass ranges between the oligomers and below the monomers. No major differences were found between the mass spectra of samples aged in light or darkness, except that deterioration was faster in light. Electron paramagnetic resonance spectroscopy revealed similar and significant amounts of radicals in films of dammar stored either in light or in darkness. It is concluded that oxidative radical reactions also take place in darkness and that differences in light and dark aging pathways are minor, although rates may differ. These findings lead to a unified explanation for yellowing of natural resin varnishes, one of the major degenerative changes in the appearance of paintings. It is also shown that the commercially available, nominally fresh resins are already in an advanced stage of oxidation and degradation. Energy-rich substances are formed upon irradiation with sunlight and are believed to restart the autoxidative chain reactions, regardless of storage conditions. As a result, varnishes are oxidized quite quickly (months) even when kept in darkness.

Digital color restoration of old paintings

Physical and chemical changes can degrade the visual color appearance of old paintings. Five digital color restoration techniques, which can be used to simulate the original appearance of paintings, are presented. Although a small number of color samples is employed in the restoration procedure, simulation results indicate that good restoration quality can be attained.

Bierstadt and Other 19th-Century American Painters in Context

The work of Albert Bierstadt (1830–1902) is put into context by a study of contemporaneous references that pertain specifically to the appearance and presentation of Bierstadt's paintings, including hanging practice, lighting, and framing. Documentary evidence is used to gain a better understanding of Bierstadt's techniques. The authors' observations, after having treated a number of paintings by Bierstadt and his contemporaries and near-contemporaries, such as Thomas Cole (1801–48) and Frederic Edwin Church (1826–1900), are also included. This discussion in tum sheds light on the criticism of Bierstadt's methods that the artist suffered during his lifetime, as well as on the special problems of preservation of certain of Bierstadt's paintings.

Bierstadt and Other 19th-Century American Painters in Context

The work of Albert Bierstadt (1830–1902) is put into context by a study of contemporaneous references that pertain specifically to the appearance and presentation of Bierstadt's paintings, including hanging practice, lighting, and framing. Documentary evidence is used to gain a better understanding of Bierstadt's techniques. The authors' observations, after having treated a number of paintings by Bierstadt and his contemporaries and near-contemporaries, such as Thomas Cole (1801–48) and Frederic Edwin Church (1826–1900), are also included. This discussion in tum sheds light on the criticism of Bierstadt's methods that the artist suffered during his lifetime, as well as on the special problems of preservation of certain of Bierstadt's paintings.

Assessment of steel surface roughness and waviness in relation with paint appearance

Paint appearance is an important factor in the overall product quality of steel sheet, especially in the automotive industry. The present paper deals with the functional behaviour of the surface texture according to paint appearance. The main results on the improvement of paint appearance of outer car body panels, obtained with coated and uncoated cold rolled steel, textured with EBT-rolls, is reviewed. There are different methods to relate steel sheet surface texture to the appearance after painting. From the literature it is found that waviness has a detrimental effect on the surface appearance after painting. Different roughness and waviness parameters are compared in order to find a good relation with paint appearance. The following surface texture parameters are evaluated in this study: roughness parameters Ra, peak count Pc, waviness parameters Wca and amplitude between 0.5 – 5mm (Fourier analysis) and envelope parameters motif W and Ra-macro, measured with a spherical stylus of radius 1.5mm. Classical parameters such as Ra and Pc are only able to evaluate paint appearance for one single texturing process, and within very limited range. The ability to predict paint appearance by Ra-macro and Wca also seems to be limited, because of their dependency on the roll texturing technique. Based on extensive testing, it is suggested that Fourier analysis might be the best approach to predict the appearance after painting, and this independently of the texturing process. The results clearly show the improved appearance of Sibetex textured sheets compared to conventional textured sheets. This is due to the fact that, with Sibetex sheet, a reduction in waviness can be achieved.

Development of the SIBETEX sheet having excellent drawability and paint appearance

The EBT texturing system introduces the full deterministic surface texture. The wide range of possible EBT textures makes it possible to combine deterministic EBT textures at the tandem and temper mill. The result is a new steel sheet surface with practically no waviness and a high bearing area.

The Invisible God: The Earliest Christians on Art by Paul Corby Finney

The invisible God: The Earliest Christians on Art. By Paul Corby Finney. (New York: Oxford University Press. 1994. Pp. xxviii, 319. $45.00.) Paul Corby Finney professor of Roman imperial and early church history in University of Missouri at St. Louis. From gymnasium studies in Germany in late 1950's and doctoral program at Harvard in early 1970's up through university career in mid 1990's, he has had an intense Interest in earliest literary attitudes toward and oldest material remains of early Christian art. This tome is detailed statement of his findings and challenge to traditional interpretive framework on early third century lamp decorations and catacomb paintings. Dr. Finney starts by reviewing how eighth-century Byzantine iconoclasts, sixteenth-century Protestant reformers, and modern German scholars from Adolf von Harnack to Theodor Klauser have built up an interpretation of Christianity as a religion simultaneously hostile to pictures in theory (iconophobic) and opposed to their use in practice (aniconic) (p. 10). He points out how this interpretation seemed to be buttressed on one hand by literary attacks of second-and third-century Christian apologists on pagan art, and on other hand by lack of distinctive Christian before year 200. This traditional interpretation presented appearance of catacomb paintings thereafter as fall from primitive spiritualism to crass materialism forced on educated clergy by uneducated laity. The author spends rest of his book analyzing early Christian apologetic attacks on pagan and early Christian motifs on Roman lamps and in catacomb paintings to challenge this scenario. Finney's analysis of Christian literary attack on pagan attempts to prove that apologists were not opposed to per se, but were using this genre of literature as a clever ploy (p.47) to win over philosophically inclined political elite of Roman world to sympathy for Christian cause. By attacking excesses of pagan art, apologists were showing that it was not Christians, but crass devotees of pagan gods who were really guilty of atheism, superstition, and sexual misconduct. The author posits that the reasons t nonappearance of Christian before 200 have nothing to do with principled aversion to art, with other-worldliness or with antimaterialism. The truth is simple and mundane: Christians lacked land and capital. Art required both. As soon as they acquired land and capital, Christians began to experiment with their own distinctive forms of art (p. 108). Although admitting that Christians had inherited through Judaism and strand of Hellenism belief that God was invisible, Dr. …

Removal of a wax‐resin lining and colour changes: A case study

Abstract Wax‐resin impregnation and lining can significantly alter the appearance of a canvas painting. This study investigates the possibilities for and the effects of reversing such treatments. When a subsequent structural intervention became necessary on a wax‐resin lined painting, tests indicated that reheating would cause further discolouration of the paint surface. An alternative treatment was successfully applied using a non polar organic solvent gel and a suction table treatment to extract a major quantity of the wax‐resin adhesive from the reverse. Comparative colour measurements of the paint surface confirmed that the discolouration was reversed to a certain degree. This method is an attempt to correct some of the drawbacks associated with modern wax‐resin impregnated canvases.

The changed appearance of oil paintings due to increased transparency

Using the Kubelka and Munk formula (and i?- the absence of adequate experimentally determIned data, hypothetical values), the effect of ~ge-induced increase in the transparency of oil paint IS shown to produce distortions in the rendering of forms when the thickness of the paint and dark grounds or underpainting are the basis of the artist's technique. A commonly observed result of the increase in the transparency of oil paint with age is the effect it has on paintings with a dark ground or with a localized dark underlayer, the modelling being produced by controlling the paint thickness and the extent to which the dark is obscured. While the values in the thickly painted parts hardly change with time, the mid-tones produced by thinner applications of paint become darker and merge into the shadows. In extreme cases the modelling of forms, which is expected to be grad- ual, becomes sharper; smooth rounded forms tend towards two-tone renderings with sharp transitions from light to dark. The increased transparency is usually ex- plained in art technology literature in terms of an increase in the refractive index of the oil medium. Reflection at the interface between oil and pigment grains is lessened when the index for the oil (no) increases, becoming closer to that of the pigment (!II). The reflectance R is quoted as:

The Changed Appearance of Oil Paintings Due to Increased Transparency

The Changed Appearance of Oil Paintings Due to Increased Transparency

VARNISH AND EARLY ITALIAN TEMPERA PAINTINGS

AbstractDuring the cleaning of the now dismembered San Pier Maggiore altarpiece, attributed to Jacopo di Cione and others, in the National Gallery, London, traces of discoloured varnish were found on one of the panels. The principal components of the varnish were identified as linseed oil and a resin, probably of Cupressaceae origin. It is possible that these traces are from the first, documented varnishing carried out in 1371. If Italian tempera paintings of this period were generally varnished, views held by restorers and art historians on the original surface appearance of such paintings should perhaps be reassessed. Italian documentary sources dating from the thirteenth to the fifteenth centuries were consulted for information on the varnishing of paintings, to see if this is likely to have been an exceptional occurrence. To assess the effects of varnishing described in a number of the sources, varnishes were prepared using two fifteenth-century Italian recipes and applied to test panels and effects o...

The influence of varnishes on the appearance of paintings

AbstractDespite numerous publications on picture varnishes, little information is available on their optical properties. Varnishes, however, greatly influence the appearance of paintings. Modern synthetic varnishes, used by restorers as replacements for unstable natural resin varnishes, do not produce the same amount of gloss and color saturation as traditional varnishes. Evidence is presented that molecular weight and refractive index are key factors in determining the optical properties of varnishes. Surface tension and hence molecular composition are of minor importance taking into consideration that varnishes of practical interest are all of relatively low polarity. Varnishes for Old Master paintings that aim at imitating the appearance of traditional picture varnishes should have low molecular weight and a relatively high refractive index.

The Influence of Varnishes on the Appearance of Paintings

The Influence of Varnishes on the Appearance of Paintings

塗料の微粒化と塗膜の仕上がり品質

塗料の微粒化と塗膜の仕上がり品質

Metal Protective Finishes

theoretical causes for the corrosion of iron have been discussed in detail by many authorities. All agree that complete protection would be afforded if a thoroughly waterproof coating of paint could be applied. No paint coating, however, is completely impervious to moisture, which is the basic cause of all corrosion. Furthermore, the usual thickness being not over -^ inch, the paint film is likely to be broken in service. For this reason, the initial coat of paint in contact with the metal must contain chemically active pigments which will retard or inhibit corrosion even though the film permits moisture to pass through. Red lead, lead chromate, zinc chromate and blue lead pigments have proved, through years of research and service, that they do retard and inhibit corrosion. Therefore, as a preliminary step, every metal surface should be coated with an inhibitive primer of this type. The finish coats, when applied over a suitable primer, serve as a protective coating for the primer and to provide the desired color. Finish coats, therefore, must be essentially resistant to the destructive influence of weather, sunlight and such fumes as may be present. Great improvements have been made in paint vehicles in recent years through the use of synthetic resins. They have greatly increased water resistance, hastened drying, made harder and tougher finishes, and have materially improved the appearance of outside paints by enabling them to retain their gloss for longer periods of time.