Original Hue Research Articles

Cephalopods sense light with skin

Masters of disguise, many cephalopods think nothing of changing their skin colour to blend in with the surroundings. ‘These changes primarily rely on eyesight’, say Desmond Ramirez and Todd Oakley from the University of California, Santa Barbara, USA, who explain that octopuses collect information about their setting with their large camera-like eyes before sending signals to chromatophores in the skin to change colour. However, Ramirez had noticed two reports describing how the colour-changing structures (chromatophores) in tiny biopsies of squid and octopus skin reacted to light with no input from the eyes or brain; although no one had followed up on the observations. Meanwhile, Alexandra Kingston and Thomas Cronin from the University of Maryland, Baltimore County, USA, were also pondering the possibility that cephalopod skin may respond to light because other biological structures are known to detect light. In addition, they also knew that proteins – so-called non-visual opsins that are analogous to the opsin proteins that sense light in eyes – are produced in the skin of various animals. Intrigued by the possibility that cephalopod skin is sensitive to light, both teams embarked on independent studies to see if they could identify key components of the light-sensing mechanism found in eyes in the skins of octopus, squid and cuttlefish.Collecting skin biopsies from California two-spot octopuses, Ramirez and Oakley first shone white light on the tissue and were impressed to see the colour-changing chromatophores expand when light fell on them and relax when the light went off, returning the skin to its original hue. Then, they measured how long it took the chromatophores to expand to change the skin's colour when exposed to light ranging in colour from violet to orange, finding the swiftest response to 480 nm light (blue), which coincides with the wavelength of light that the octopus's eye opsin responds to most strongly. Referring to the light reponse as light-activated chromatophore expansion (LACE), the duo then tested the skin for evidence of expression of opsin genes, and they were pleased to find expression of the gene for rhodopsin, the opsin protein that is usually produced in the eye. And when the duo tested where the rhodopsin protein was produced in the skin, they found it localised to sensory neurons distributed on the mantle surface.Focusing on several cephalopods – two cuttlefish and a squid – Kingston and Cronin decided to investigate whether they could identify components of the molecular machinery that is essential for converting light detection into a behaviour. As they knew that light activates rhodopsin in the retina, triggering a cascade of protein interactions that culminate in an ion channel opening to signal light detection, the pair of scientists began searching for key proteins in the rhodopsin signalling cascade in the skin of the common cuttlefish, the broadclub cuttlefish and the longfin inshore squid. Using a battery of molecular techniques, Kingston and Cronin identified rhodopsin in the skins of both cuttlefish and the squid, and they also found other proteins that are essential for the light sensing in the animals’ skin. Next, they teamed up with Alan Kuzirian and Roger Hanlon to look in closer detail at chromatophores isolated from different regions of the squid's mantle and found that the light-sensing cascade proteins were actually in the chromatophores. ‘The very same structures that show behavioral responses are actually themselves light-sensitive’, says Cronin.So, both teams present compelling evidence that cephalopods may have adapted the cellular mechanism that detects light in eyes for light sensing in skin, and Ramirez and Oakley have collected the first recording of the skin's sensitivity across the visual spectrum. In addition, Kingston and Cronin suggest that squid chromatophores directly sense the light that they respond to through three possible mechanistic scenarios: they could interact directly with adjacent cells, through the gap junctions between muscle cells or through nerve fibres to communicate with the central nervous system, providing information about the animals’ surroundings while it tries to blend in.

Antireflection coating on silk fabric fabricated from reactive silica nanoparticles and its deepening color performance

In this study, we reported the functionalization of raw silica nanoparticles (SiNPs) with (2-ethyl hydrogen sulfate) sulfonyl (EHSS) groups and their utility as a building block to produce a washing durable antireflection coating on silk fabric. The raw SiNPs were synthesized via classical Stober method and subsequently reacted with (3-methacryloxypropyl) trimethoxysilane, allowing for the raw particle surfaces to be left with ethoxy and methoxy groups. Then, EHSS groups were immobilized onto the SiNP surfaces through the reactions with EHSS group-terminated silane coupling agents. The EHSS functionalization was confirmed by Fourier transform infrared spectroscopy and elemental analysis. These EHSS group-functionalized SiNPs were applied onto silk fabrics by following a dip-coating technique under mild conditions. During this process, the ethoxy and methoxy groups were involved in the condensation reactions to give a cross-linked silica coating that was covalently attached onto the fiber surface through the reactions between EHSS groups and silk fibers. The coating was demonstrated to have a nano-porous microstructure and provided fibers with nano-roughened surfaces, which showed high efficiency in antireflection and increasing light transmission. Since the transmitted light would be selectively absorbed by the dyestuff, the coating applied onto colored silk fabrics gave rise to a more than 30 % increase of the color strength without changing the original hues of the fabrics. Furthermore, being sharply different from the common darkening resins consisting of polysiloxanes and fluorochemicals, the silica coating brought darkening effects without compromising the inherent hydrophilicity of silk fabrics.

L’imbrunimento come criterio di qualità delle carte utilizzate nei libri a stampa dei secoli XV e XVI

The aim of this research is the study, from the point of view of preservation, of a collection ofmore than ten thousand books printed in the 15th and 16th centuries, now kept in the Episcopal Seminary’s Library of Padua. Particular attention was paid to the state of preservation of the paper, singling out the cases where a discolouring of the original white hue had occurred. Such discolouring can take on various gradations, from yellow to brown, which may indicate increasing gravity of degradation. The data detected was then assessed in the light of dates and locations of printing, throwing up evidence of varying behaviour for the books produced in main Italian printing centres and the principal cities of Europe.

看板の色変更に関する研究

Two experiments were carried out to determine signboard color modification rules for a harmonized streetscape in which signboards are visible and the identity of logos is clear. Various color-modified logos were displayed in the first rate their impression. It was found that it is preferable to maintain the hue of the logos similar to that of the original in the experiment 1. It was suggested that retaining the original hue of logos on signboards improves their visibility and makes the streetscape aesthetically appealing from the experiment 2.

The original colours of fossil beetles

Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.

Museum Laboratories: Where Art Meets Science

Museum Laboratories: Where Art Meets Science

Pigment Selection for an Inkjet Ink Set with Balanced Lightfade Performance

Careful pigment selection for an inkjet printer can achieve balanced lightfade performance. When a print fades from light exposure, commonly each colorant fades at a different rate. This results in an unwanted hue shift in addition to the overall loss in density. In a balanced system, each colorant fades at approximately the same rate. As a result, the amount of hue shift is reduced. The faded print is perceived as less objectionable to the user when the original hues are maintained. In order to create a balanced system, samples are printed with pigment and pigment blend candidates on a variety of media types. Those samples are exposed in a lightfade chamber, and density changes are measured over time. This data is used to select candidates with similar lightfade performance for each colorant of the system. Instead of attempting to maximize the lightfade performance of each colorant, other desirable performance attributes can be considered, such as chroma and cost. The achievement of a balanced lightfade system results in a more complete solution to the customer.

A multivariate contrast enhancement technique for multispectral images

Multispectral and true-color images are often enhanced using histogram-based methods, usually by adjustment of color components after transformation to a selected secondary color system. Enhancement aimed toward the preservation of certain important perceptual qualities generally calls for the secondary coordinate system to be perceptually based. However, independent modification of the secondary components seldom uses the full extent of the RGB gamut unless some color values are clipped at the RGB boundaries. Preserving perceptual attributes is sometimes less important than obtaining the greatest possible color contrast improvement. This is especially true for color composites derived from multispectral images, which have no significant basis in human perception. A new multivariate enhancement technique the authors have named is able to exploit nearly the full RGB extent without clipping. While not generally based upon a perceptual model, the method can preserve original hue values when parameters are chosen properly. Experimental results of histogram explosion are presented, along with an analysis of its computational complexity. >

Bernard Leach and the Japanese Folk Craft Movement: The Formative Years

Formative years in any art movement are difficult to relate with accuracy. At the time, those closely involved are too excited about what they are doing to waste what appears to be valuable time committing events to paper. Only much later do they reflect on the past and write it down. Two things are likely to happen during this essentially autobiographical process (especially since artists are not always writers by nature). Either they skate over vital events, happenings, or relationships (often because of personal reasons). Or their writing takes on a rosy, nostalgic hue that makes it difficult for the outsider to judge just how much of what is told was true for the artist-writer at the time, and how much is a product of his or her post-rationalization. It is then the task of the critic, art historian, biographer, or-in this case-anthropologist, to retell the tale, restore the painting to its original hues, and try to see the formative years as they 'really' were. That it is an anthropologist, rather than an art historian, who is involved in the 'restoration' points to an interesting aspect of East/West cultural politics that is only just beginning to surface. Much has now been written, notably by Edward Said,1 on the way in which the West has tried to dominate, structure, and have authority over the East by means of a set of representations which Said has called 'Orientalism'. What has not been emphasized so much is the way in which one or two societies, originally the object of Orientalism, have been able recently to reinterpret its qualities, turning perceived weakness into strength, negative denigration into positive pride, and their dominated masses into a dominating people. As I have tried to show elsewhere, Japan is one such society.2 In their successful attempts to create what amounts to an 'inverse Orientalism' visa-vis the West, the Japanese now promulgate their art and aesthetics as part of a new Eastern 'spiritualism' that is seen to be vastly superior to Western 'materialism'. It is in this context that the role of Bernard Leach (1887-1979) in the formative years of what has now come to be known as the Japanese mingei, or 'folk craft', movement takes on added significance. In the first place, Leach allowed water to 'flow uphill', by taking Western ideas about art to the East (and hence briefly counteracted the general fashion for japonisme); secondly, in so doing, he helped a group of Japanese rediscover their 'Oriental' cultural origins. But as one might expect, perhaps, in a situation of this nature, matters are by no means clear-cut. Leach wrote at some length on his eventful life in a book that was sub-titled 'memoirs, portraits and essays',3 but his accounts there, and elsewhere,4 are somewhat frustrating for anybody trying to find out precisely how involved Leach was with the development of the folk craft movement in Japan, and what the nature of his relationships was with its founding members: the philosopher and critic, Yanagi S6etsu (1889-1961), together with three eminent potters, Tomimoto Kenkichi (1886-1963), Kawai Kanjiro (1890-1966), and Hamada Shoji (1894-1978). I say 'frustrating' for a reason. The parallels in thought between Yanagi Soetsu (or Muneyoshi as, strictly speaking, he should be called) and William Morris are too obvious to be ignored.5 The division of the arts into 'greater' and 'intellectual' (jotemono) and 'lesser' and 'non intellectual' (getemono) categories; the search for an art made for the people and by the people; the exaltation of the spirit of the Gothic, whereby 'community' was valued over 'individualism'; and the emphasis on hand, rather than machine, made work, and on function as a criterion of 'beauty' and 'truth'-the similarities are too numerous to be accidental. And yet, in Japan, the concept of mingei-or 'people's art' as the phrase was originally translated-has been made out to be unique to that country, owing little, if anything, to Western aesthetics. I have argued elsewhere that ideals about

The nature of infant memory for hue

The question of whether infants remember hue categorically or in terms of precise hue identity was investigated with 32 infants (mean age 20·0 weeks). Eight infants participated in a pre‐test designed assess the discriminability of hues from the same category and a further 24 infants were assessed for recognition of these hues. These infants were familiarized to one hue and tested for recognition of this hue either immediately or following a five‐minute delay. Recognition was assessed by means of a series of paired comparisons: the original hue paired with itself (control), with a novel same‐category hue or with a novel new‐category hue. Additionally, ‘false’ or categorical recognition was tested by comparing the novel same‐category hue to the novel new‐category hue. On the immediate test, infants responded as if they had remembered the exact identity of the original hue—although there was also evidence of sensitivity to categorical relationships between hues. On the delayed test, however, infants appeared to remember only the category of the original hue. Control procedures adopted in the study made it unlikely that these results were confounded by such factors as differential hue preferences or hue brightness.

Protein staining by Coomassie Brilliant Blue G‐250: Unique color rendering in iron‐toned prints

AbstractBlack‐and‐white photographs of protein staining by Coomassie Brilliant Blue G‐250 may be iron‐toned by a modified procedure to obtain good reproduction of the original hue and range of intensities. A suitable paper and a film for transparencies are specified for printing from a given negative.

Hue Matching and Hue Oddity in Pigeons: Is Explicit Training Not to Peck Incorrect Hue Combinations a Sufficient Condition for Transfer?

In Experiment 1, pigeons were trained in a two-key higher-order conditional discrimination paradigm in which white lines tilted 0° or 90° were superimposed on colored backgrounds to signal matching or oddity contingencies. When the red and green training hues were replaced by blue and yellow during transfer, there was no transfer of appropriate responding to novel hues. In Experiment 2, pigeons were trained in a simple two-key matching-to-sample paradigm with red and green hues. A series of nine transfer tests was conducted in which either one or two novel hues were substituted for either one or both of the original training hues. The results of the transfer tests failed to provide strong evidence for concept learning and suggest that explicit training not to peck incorrect comparisons is not a sufficient condition for successful transfer of hue matching and oddity in pigeons.

A history of six years' thiouracil treatment in a brown Leghorn hen.

The history is recorded of a Brown Leghorn hen that received 0·5% thiouracil in the diet from 9 weeks of age until the bird was over 6 years old, when it was killed. During this period certain sections of the plumage exhibited a series of new and different pigments, while others remained relatively unchanged. The last category comprised the regions originally salmon; the feathers were structurally altered, but continued a duller shade of the original hue. Feathers of the dorsal tracts and the smaller wing coverts showed shades of orange and rust, resembling the modified male during the first 3 years. Thereafter, these feathers gradually became pale gold and small, but true female segments reappeared surrounding the shaft. Large wing and tail feathers were not greatly changed except the two most distal secondaries. At the end of the experimental period, proximally located, regenerating secondaries were laying down metallic black with some coarse brown mottling. Eggs continued to be laid, but intervals between clutches were greatly lengthened. Tests for fertility by artificial insemination were made at 3 and 6 years of age. Viable chicks were hatched at both times. Dissection of embryos and chicks in the second series showed greatly enlarged thyroids. Possible explanations of the appearance of black feather pigments in remiges and rectrices during such long-continued treatment with thiouracil are considered.