colours – Lightsources.org

Wild blue wonder: X-ray beam explores food color protein

2021/12/012021/12/09

A natural food colorant called phycocyanin provides a fun, vivid blue in soft drinks, but it is unstable on grocery shelves. Cornell’s synchrotron is helping to steady it.

In food products, the natural blues tend to be moody.

A fun food colorant with a scientific name – phycocyanin – provides a vivid blue pigment that food companies crave, but it can be unstable when placed in soft drinks and sport beverages, and then lose its hues under fluorescent light on grocery shelves.

With the help of physics and the bright X-ray beams from Cornell’s synchrotron, Cornell food scientists have found the recipe for phycocyanin’s unique behavior and they now have a chance to stabilize it, according to new research published Nov. 12 in the American Chemical Society’s journal BioMacromolecules.

“Phycocyanin has a vibrant blue color,” said Alireza Abbaspourrad, the Youngkeun Joh Assistant Professor of Food Chemistry and Ingredient Technology in the Department of Food Science in the College of Agriculture and Life Sciences. “However, if you want to put phycocyanin into acidified beverages, the blue color fades quickly due to thermal treatment.”

Ultra-white beetle scales may be the key to more sustainable paint

2019/08/292019/08/29

An international team of researchers has managed to mimic the colour of the Cyphochilus beetle scales – one of the brightest whites in nature, thanks to the ESRF’s imaging capabilities. This could help the development of ultra-white, sustainable paints.

Cyphochilus beetle scales are one of the brightest whites in nature. Until now, researchers did not known how their ultra-white appearance is created. X-ray nanotomography experiments at the ESRF have shown that the nanostructure in their tiny scales creates the colour, not the use of pigment or dyes.
Andrew Parnell, from the University of Sheffield and corresponding author of the study said: “In the natural world, whiteness is usually created by a foamy Swiss cheese-like structure made of a solid interconnected network and air. Until now, how these structures form and develop and how they have evolved light-scattering properties has remained a mystery.”
The findings show that the foamy structure of the beetles’ scales has the right proportion of empty spaces, in a highly interconnected nano-network, which optimise the scattering of light – creating the ultra-white colouring.

Image: Andrew Denison and Stephanie Burg in the experimental hutch of beamline ID16B.

In a first, researchers identify reddish coloring in an ancient fossil mouse

2019/05/212019/05/23

X-rays reveal an extinct mouse was dressed in brown to reddish fur on its back and sides and had a tiny white tummy.

Researchers have for the first time detected chemical traces of red pigment in an ancient fossil – an exceptionally well-preserved mouse, not unlike today’s field mice, that roamed the fields of what is now the German village of Willershausen around 3 million years ago.
The study revealed that the extinct creature, affectionately nicknamed “mighty mouse” by the authors, was dressed in brown to reddish fur on its back and sides and had a tiny white tummy. The results were published today inNature Communications.
The international collaboration, led by researchers at the University of Manchester in the U.K., used X-ray spectroscopy and multiple imaging techniques to detect the delicate chemical signature of pigments in this long-extinct mouse.

Image: In this image showing the fossil chemistry of an ancient mouse, blue represents calcium in the bones, green is the element zinc which has been shown to be important in the biochemistry of red pigment and red is a particular type of organic sulfur. This type of sulfur is enriched in red pigment. When combined, regions rich in both zinc and sulfur appear yellow on this image, showing that the fur on this animal was rich in the chemical compounds that are most probably derived from the original red pigments produced by the mouse. (10.1038/s41467-019-10087-2)

The secret to Rembrandt’s impasto unveiled

2019/01/102019/01/10

Rembrandt van Rijn revolutionized painting with a 3D effect using his impasto technique, where thick paint makes a masterpiece protrude from the surface. Thanks to the ESRF, three centuries later an international team of scientists led by the Materials Science and Engineering Department of TU Delft and the Rijksmuseum have found how he did it.

Impasto is thick paint laid on the canvas in an amount that makes it stand from the surface. The relief of impasto increases the perceptibility of the paint by increasing its light-reflecting textural properties. Scientists know that Rembrandt, epitome of the Dutch Golden Age, achieved the impasto effect by using materials traditionally available on the 17^thcentury Dutch colour market, namely lead white pigment (a mixture of hydrocerussite Pb₃(CO₃)₂.(OH)₂ and cerussite PbCO₃), and organic mediums (mainly linseed oil). The precise recipe was, however, unknown until today.

Image: Scientist Marine Cotte on beamline ID21.
Credit: Steph Candé.

Enlightening yellow in art

2018/06/212018/06/21

Scientists from the University of Perugia (Italy), CNR (Italy), University of Antwerp, the ESRF and DESY, have discovered how masterpieces degrade over time in a new study with mock-up paints carried out at synchrotrons ESRF and DESY. Humidity, coupled with light, appear to be the culprits.

The Scream by Munch, Flowers in a blue vase by Van Gogh or Joy of Life by Matisse, all have something in common: their cadmium yellow pigment. Throughout the years, this colour has faded into a whitish tone and, in some instances, crusts of the paint have arisen, as well as changes in the morphological properties of the paint, such as flaking or crumbling. Conservators and researchers have come to the rescue though, and they are currently using synchrotron techniques to study in depth these sulphide pigments and to find a solution to preserve them in the long run.

“This research has allowed us to make some progress. However, it is very difficult for us to pinpoint to what causes the yellow to go white as we don’t have all the information about how or where the paintings have been kept since they were done in the 19^th century”, explains Letizia Monico, scientist from the University of Perugia and the CNR-ISTM. Indeed, limited knowledge of the environmental conditions (e.g., humidity, light, temperature…) in which paintings were stored or displayed over extended periods of time and the heterogeneous chemical composition of paint layers (often rendered more complex by later restoration interventions) hamper a thorough understanding of the overall degradation process.

>Read more on the ESRF website

Image: Some of the mock-up paints, prepared by Letizia Monico. Credits: C. Argoud.

Combining X-ray techniques for powerful insights into hyperaccumulator plants

2018/04/042018/04/12

The complementary power of combining multiple X-ray techniques to understand the unusual properties of hyperaccumulator plants has been highlighted in a new cover article just published in New Phytologist.

X-ray fluorescence microscopy (XFM) at the Australian Synchrotron has been used by a consortium of international researchers led by Dr Antony van der Ent of the Centre for Mined Land Rehabilitation at The University of Queensland, in association with A/Prof Peter Kopittke of the School of Agriculture and Food Science also at The University of Queensland.

The XFM technique generates elemental maps showing where elements of interest are found within plant tissue, seedlings or individual cells.
Visually striking images (obtained at the XFM beamline) show various hyperaccumulator plants, on the cover of the April issue of New Phytologist. In the images each element is depicted in a different colour, making up a red-green-blue (RGB) image.

“Hyperaccumulator plants have the unusual ability to accumulate extreme concentrations of metals and metalloids in their living tissues,” said van der Ent.
“Hyperaccumulators are of scientific interest because whilst metals are normally toxic to plants even at low concentrations, these plants are able to accumulate large concentrations without any toxic effects,” he added

Image: X‐ray Fluorescence (XRF) elemental maps of hyperaccumulator plants. The tricolour composite images show (left to right) root cross‐section of Senecio coronatus (red, iron; green, nickel; blue, potassium); and seedlings of Alyssum murale (red, calcium; green, nickel; blue, Compton scatter).
Credit: A. van der Ent.

A colour photography pioneer comes to light thanks to the synchrotron

2018/03/192018/03/21

The colour prints of Louis Ducos du Hauron, an unknown pioneer of colour photography, have been put under the infrared and X-rays at the ESRF, the European Synchrotron (Grenoble, France) to better understand the methods he used. A team of researchers and curators from the ESRF, CNRS, C2RMF , Musée d’Orsay, École nationale supérieure Louis Lumière, the faculty of Science and Engineering of the Sorbonne University, the Chimie Paris Tech and a private photography conservator and curator has published the results of this study in Angewandte Chemie.

Who invented colour photography?

To this question, most people would reply “the brothers Lumière”. Their procedure “autochrome” is recorded into posterity because the brothers commercialised it with success. However, a photography pioneer has been kept in the shadow: Louis Ducos du Hauron. This is despite the fact that he patented an animated image-processing method in 1864, the same year that Louis Lumière was born. He was the first one to produce three-color prints using three negatives printed into three colour positives (one red, one yellow and one blue), in a similar manner to how printers today function.

As if he were a cook, Ducos du Hauron spent his life creating “recipes” – procedures based on scientific experimentation- to achieve a faithful reconstruction of reality through colour photographs. He photographed each scene through green, orange, and violet filters, then printed his three negatives on three thin films of dichromate gelatin containing red, blue, and yellow pigments, the complementary colours of the filters used for the negatives. When the three positives were superimposed, a full-colour photograph resulted.

Image: General principle of three-color carbon printing developed by Ducos du Hauron. (Full image here)
Credit: ESRF