Tattoo Ink

Welcome back. Way back when, I blogged that I wasn’t wild about tattoos (see Temporary Tattoos Addendum). But I added: That’s not to say that I didn’t love temporary tattoo transfers when I was about 7 years old and they came in packs of bubble gum and boxes of Cracker Jack--even if you could just about wash them off. 

In those years, the only people I saw with tattoos (away from fairgrounds) were WWII veterans and later, veterans of the Korean conflict. Now, it seems that everyone has at least one tattoo (surveys vary, generally at least 30% U.S. population). And these tattoos don’t wash off. 

Poster of World War II veteran with D-Day tattoos for salute to Honor Flight Southland that transports California veterans from Los Angeles, San Bernadino and Orange counties to Washington, D.C. to visit their memorials (from www.tattoodo.com/articles/20-world-war-ii-tattoos-for-dday-4158).

In fact, as John Swierk, Ph.D., a Binghamton University chemistry professor points out, the inks used for today’s tattoos are not regulated in the U.S., even though tattoo artists must be licensed. The Food & Drug Administration classifies tattoos and tattoo ink as cosmetic products. 

Prof. Swierk and students in his lab have been studying the safety and photochemistry of tattoo inks. They have analyzed the composition of nearly 100 inks. He presented the results to date at this fall’s meeting of the American Chemical Society. I thought you’d find the topic and their work of interest.

A Bit About Tattoo Inks
Tattoos are inks, composed of a pigment dissolved in a liquid carrier, inserted into the skin to produce the color.

The carrier solution transports the pigment to the middle layer of skin, the dermis, and typically increases its solubility. It can also control the viscosity of the ink solution and may include an anti-inflammatory ingredient.

Tattoo’s depth into the dermis layer (from tattooing101.com/learn/tattoo-equipment/ink/).

The pigment could be a molecular compound, such as a blue pigment; a solid compound, such as white titanium dioxide; or a combination of the two, such as light blue ink. Tattoo ink pigments are manufactured by large companies and are the same as those used for everything, paint or textiles. No company makes pigments specifically for tattoo ink.

Prof. Swierk and the students interviewed tattoo artists and learned they could quickly identify the brand of ink they preferred, though they knew little about the ink contents.

Tattoo artist at work (from tattooglee.com/tattoo-needle-definition/).

Ink Analyses
To analyze the particle size and molecular composition of tattoo pigments, the researchers employed multiple analytical techniques (UV-visible, infrared, nuclear magnetic resonance and Raman spectroscopies; liquid chromatography and inductively coupled plasma mass spectrometries; microwave acid digestion, electron microscopy). They identified specific pigments in some inks and found ingredients not listed on the label (e.g., ethanol).

Their analyses frequently highlighted something disconcerting to Prof. Swierk. He reported, for example, that analysis of many inks suggested the presence of an azo-containing dye. While many azo pigments are not health concerns when chemically intact, they can be degraded by bacteria or ultraviolet light into another nitrogen-based compound that is a potential carcinogen.

Another example is that about half of the inks analyzed using electron microscopy contained particles smaller than 100 nanometers. Particles of that size can get through the cell membrane and potentially cause harm.

Tattoo removal is a general cause for concern. How the ink breaks down (e.g., after laser photolysis) and what products form are not fully known. Analytical techniques similar to those used to study pigments can be used for analysis, focusing on products potentially harmful to human health.

Laser tattoo removal (from thegardenmedspa.com/laser-tattoo-removal/).

Wrap Up
The researchers plan to complete testing, have the data peer reviewed, then add the information on the composition and potential risks of different inks to the website they developed, What’s in My Ink?

Their goal is to help the artists as well as consumers make informed decisions and understand the accuracy of the information.

Thanks for stopping by.

P.S.
Exposing what’s in tattoo ink:
Article on EurekAlert! website with American Chemical Society meeting presentation abstract: www.eurekalert.org/news-releases/960976
YouTube video of review of work: www.youtube.com/watch?v=239bEv4pTTo&list=PL-qHxGvFeZV11YAygI6lgZ6yOq2nWwvv7&index=3

2020 article on tattoo ink safety from India’s myUpchar: www.firstpost.com/health/is-your-tattoo-ink-safe-7778391.html
2021 NPR article on tattoo ink safety: www.npr.org/sections/health-shots/2021/02/13/965549858/as-scientists-study-tattoo-ink-safety-europe-bans-two-widely-used-pigments
2021 systematic review of tattoo pigment degradation products in Journal of Exposure Science and Environmental Epidemiology: www.nature.com/articles/s41370-021-00364-y

Online Art Viewing

Welcome back. To make amends for not blogging about art in years, I have two studies to review. Although the two are quite different, both focus on appreciating how viewing art can improve wellbeing--even when the viewing is virtual. I hope you’ll find them of interest.

Viewing Art and Non-Art
Researchers with Austria’s University of Vienna, Germany’s Max Planck School of Cognition, and Netherland’s Max Planck Institute for Psycholinguistics examined how online art and cultural engagements impact mental states.

They recruited 84 participants (65 women, 17 men, 1 other, 1 unknown; average age 35, ranging from 21 to 74; from the Americas, 48%, Europe, 43%, Asia, 8% and Africa, 1%), and exposed 40 to an “art” condition, 44 to a “non-art” condition.

Both conditions, taken from Google Arts and Culture, consisted of single online images whose visual details could be zoomed in on and related text.

The “art” condition drew upon an exhibition of Monet’s The Water Lily Pond from the National Gallery, London. 

Claude Monet’s “The Water Lily Pond” (from artsandculture.google.com).

The “non-art” condition was A Bitesize History of Japanese Food; Explore a mouthwatering box of Japan’s iconic cuisine, which included a diagram in the shape of a bento box, containing photos and facts on the history and traditions of Japanese food.

"A Bitesize History of Japanese Food" (from artsandculture.google.com).

Assessing the Effects
A pre-study survey collected participants’ demographic and life status, personality traits and art interest and expertise.

To measure the impact of viewing the online conditions, the researchers assessed six wellbeing dependent variables in both pre- and post-viewing surveys: (1) De Jong Gierveld 6-Item Loneliness Scale; (2) State-Trait Anxiety Inventory; (3) Satisfaction with Life scale; (4) Subjective Wellbeing scale; and (5,6) two questions to rate positive and negative mood.

The Findings
On average, participants engaged with each condition for only about 1.5 to 2 minutes, describing the experience in similar positive-valence emotions and cognitive states (e.g., serenity, happy, stimulated, insight), with low levels of negative emotions (e.g., fear, embarrassed, anger).

Overall, the study found a significant impact on several wellbeing variables. The researchers concluded that online cultural engagement, including but not limited to fine art, appears to be a viable approach to support individuals’ mood, anxiety, loneliness and wellbeing, especially when the content is beautiful, meaningful and inspiring to the viewer.

Average self-reported ratings (means and standard deviations) for each time condition per group; number of participants, a = 36, b = 42; for a positive impact, negative mood, anxiety and loneliness should decrease while positive mood, life satisfaction and wellbeing should increase (from Table 1, www.frontiersin.org/articles/10.3389/fpsyg.2022.782033/full).

Online Museum Tours
Research has shown that older adults' wellbeing and quality of life are negatively impacted by both social isolation and frailty; the latter is defined as an aging-related syndrome of physiological decline, characterized by marked vulnerability to adverse health outcome. A team of investigators, led by a researcher with the University of Montreal, joined with the Montreal Museum of Fine Arts to gauge the potential benefits of online museum tours.

Montreal Museum of Fine Arts (museesmontreal.org/en/museums/montreal-museum-of-fine-arts).

They screened and ultimately enlisted 106 Montreal community dwellers aged 65 and over, randomly assigning half to a 3-month cycle of weekly online museum tours and half to be held as control, abstaining from any cultural activities.

Each online 45-minute museum visit was performed with 6 to 8 participants and a trained guide, for a total of 8 groups. The visits included presentation of objectives, a dialogic-style tour with trained museum guides, and open-ended discussion. The tour content consisted of artwork, live discussions animated by tour guides, ancillary information on the artwork or artists from tour guides, and videos about specific works or artists.

Assessing the Effects
Social isolation, wellbeing, quality of life and frailty were assessed for both groups using validated scales at baseline (M0) and after 3 months (M3). The museum tour group showed significant improvements in social isolation, wellbeing, quality of life and especially frailty scores compared to the control group.

Mean (standard deviation) changes in frailty of control and tour groups from baseline to 3 months; calculated from questionnaire providing a score ranging from 0 (vigorous) to 18 (severe frailty) (from Table 2, www.frontiersin.org/articles/10.3389/fmed.2022.969122/full).

The study suggests that a 3-month cycle of weekly online museum tours may foster a sense of connectedness and thereby improve mental and physical health in community-dwelling older adults.

Wrap Up
Living within a metro ride to Washington D.C. for over 20 years afforded the opportunity to visit the National and other museums. How often did we take advantage of it? Would online viewing have made a difference? Would it have improved our wellbeing? I’ve got to think about that, especially now that I’m retired and those museum are far away. How about you?

Thanks for stopping by.

P.S.
Study of online art and non-art viewing in Frontiers in Psychology journal: www.frontiersin.org/articles/10.3389/fpsyg.2022.782033/full
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/958286

Google Arts & Culture:
artsandculture.google.com
en.wikipedia.org/wiki/Google_Arts_%26_Culture

Study of online museum tours in Frontiers in Medicine journal: www.frontiersin.org/articles/10.3389/fmed.2022.969122/full
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/961581

The Most Creative Age

When does creativity
glow brightest (from
www.kisspng.com/png-creativity-472384/)?

Welcome back. Are you creative? Do you or did you ever have the ability to produce original or unusual ideas or make something new or imaginative? Did your creativity peak at a certain age?

A number of studies have examined how old people were when they were most creative, when they did their best work. The ages vary with the field or endeavor, and you may find fault with the criteria used for rating creativity; but you still might be interested to see how your creative peak--whether past, present or future--compares to that of others.

Peak Creativity in Forms of Art
In separate investigations, a researcher from the Erasmus School of Economics in the Netherlands determined the age when modern art painters, writers and classical music composers produced their best work.

To assess the most creative age of painters in a 2013 study, he began with the 189 highest-price paintings. The average age of the painters who created these paintings was nearly 42.

For writers, he considered Nobel Prizes for Literature. In a 2014 study, he found the average age of 89 Nobel Laureates approached 45 when they wrote their prize-winning work.

And for his 2016 study of composers, he identified the 100 most popular classical music composers from a website that documents the most often performed works. The average age at which they composed their most popular work was about 39.

Peak Creativity in Sciences
Determining the age when Nobel Laureates did their prize-winning work was the approach taken earlier by researchers affiliated with Northwestern and Ohio universities and the National Bureau of Economic Research. Their 2011 study analyzed 525 Nobel Laureates in physics (182), chemistry (153) and medicine (190) from 1901 to 2008.

They found the differences among the three fields were small compared with the differences over time within each field. For example, before 1905, 60% to 70% of prize-winning work was done before age 40, with about 20% before age 30. By the end of the century, Nobel prize-winning work before age 30 was near 0%.

The mean age at which Nobel Laureates produced their prize-winning work in physics, chemistry and medicine from 1901 to 2008 (whole), through 1905 (early) and from 1985 (late); standard errors in parentheses (from www.pnas.org/content/108/47/18910).

The age increase mirrors both the increase in training--how long it takes to acquire foundational knowledge--and the decrease in theoretical contributions.

Regarding training, most Nobel laureates in these fields earned their PhDs by age 25 in the early 20th century. The number dropped substantially by the end of the century.

As for the nature of the contribution, theoretical/deductive contributions tend to come earlier in scientific careers than do inductive contributions, which build more on the knowledge associated with increased training.

Peak Creativity in Economics

The Nobel Memorial Prize in Economic Sciences, officially “Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel,” was established in 1968, not by Alfred Nobel’s will (from www.geni.com/projects/Nobel-Prize-Winners-in-Economics/8200).

In a recent study of age and creativity--the study that got me started--collaborators from Ohio State and Chicago universities examined 31 Nobel Laureates in economics.

By ranking the laureates on a scale from most conceptual/deductive to most experimental/inductive, they found the conceptual laureates made their most important contribution at an age of about 25, while experimental laureates peaked in their mid-50s.

Wrap Up

Comment on creativity
attributed to Einstein.

Well? How do you compare? Don’t lose sight of the many other forms of creativity or the other criteria for judging creativity.

If you’re into the mystical, you’ll appreciate how the researcher who studied painters, writers and composers expanded his assessment. Besides determining the average ages of peak creativity, he calculated the percentages of lifespan they had lived to that point.

It turns out that those percentages for painters and composers, 62% and 61%, are almost exactly the golden ratio, also known as the divine proportion among other labels. (Writers, at 57%, are off a bit.)

Apparently, Euclid studied the mathematical properties of the golden ratio around 300 BC, and its proportions pop up in music, art, architecture and patterns of nature. If you’re reading this, it’s too early for you to calculate your ratio. Thanks for stopping by.

P.S.
Study of when painters did their best work in Creativity Research Journal: www.tandfonline.com/doi/full/10.1080/10400419.2013.843912
Study of when writers did their best work in Creativity Research Journal: www.tandfonline.com/doi/abs/10.1080/10400419.2014.929435
Study of when composers did their best work in Creativity Research Journal: www.tandfonline.com/doi/full/10.1080/10400419.2016.1162489
Article on forms of art creative peak on Washington Post website: www.washingtonpost.com/news/wonk/wp/2016/06/23/when-you-will-most-likely-hit-your-creative-peak-according-to-science/
Study of scientific creativity in Proceedings of National Academy of Sciences: www.pnas.org/content/108/47/18910
Study of economics creativity in De Economist journal: link.springer.com/article/10.1007/s10645-019-09339-9
Article on economics creativity on EurekAlert website: www.eurekalert.org/pub_releases/2019-04/osu-cin042319.php
Golden ratio: en.wikipedia.org/wiki/Golden_ratio

The Scream’s Clouds

Welcome back. On occasion, I’ve ventured into the world of art, where I have no background (among other blog posts Authenticating Artwork Computationally and Authenticating Artwork Addendum). A study of the painting The Scream by the Norwegian artist Edvard Munch (1863–1944) has me venturing again. 

Edvard Munch’s The Scream
(1893), The National Gallery,
Oslo, Norway.

You’re probably familiar with the painting or at least the character portrayed, whether from reproductions, horror movies or Halloween costumes. But the study by researchers from the UK’s Oxford and London universities and Rutgers University focused on the sky, not the character.

Munch’s graphical depiction may be the earliest visual documentation of a type of cloud largely unknown to atmospheric science at the time.

The Scream
The dates of artwork can be important when trying to identify possible sources of inspiration. Unfortunately, Munch is known to have been indifferent about dating his work, in addition to producing many versions of the same painting.

There are four known versions of The Scream in paint and pastel. The National Gallery in Oslo, Norway, holds a painted version, dated 1893; the Munch Museum in Oslo holds a pastel version, dated 1893, as well as a painted version, undated but thought to be 1910; and a second pastel version, dated 1895, was sold for nearly $120 million in 2012. Munch also produced a lithograph version in 1895.

A glance at the painting suggests the character is screaming, yet the character was attempting to smother the sound according to Munch’s diary entry in 1892 and his later description of the image: “…the sun was setting, and the clouds turning blood red. I sensed a scream passing through nature; it seemed to me that I heard the scream. I painted this picture, painted the clouds as actual blood. The color shrieked…”

Possible Sources of Inspiration
Presuming that Munch’s painting captured the sky as he actually saw it, the researchers judge the event to have been either an abnormal or particularly striking sunset, a sunset affected by a volcanic eruption or some other meteorological phenomenon.

The volcanic sunsets caused by the August 1883 eruption of Krakatau in what is now Indonesia is often posited as the cause of Munch’s blood-red clouds. Munch’s whereabouts and the dates of Krakatau-affected sunsets over northern Europe narrow his possible observation to the winter months of 1883.

An alternative explanation, which the researchers favor over volcanic sunsets, was put forth in a 2017 study by a meteorological consultant from Norway and researchers from the University of Oslo and Norwegian Meteorological Institute. That study attributed Munch’s observation to nacreous clouds.

Photographs of nacreous clouds taken on 20 Jan 2008 from Leirsund, southern Norway, at times: (top left) 1508:56, (top right) 1532:47, (middle left) 1533:17, (middle right) 1534:20, (bottom left) 1546:35, and (bottom right) 1548:11 UTC. (Photos by F. Prata from journals.ametsoc.org/doi/10.1175/BAMS-D-17-0144.1)

Nacreous clouds are seldom seen, filmy sheets, unbelievably bright with vivid and slowly shifting iridescent colors, curling and uncurling in the winter polar stratosphere at altitudes of 15,000–25,000 meters (49,000–82,000 feet). They are best seen within two hours after sunset or before dawn.

In Support of Nacreous Clouds
For the study, the researchers determined from the literature that nacreous clouds are sometimes observed during cold winter months in southern Norway. The clouds produce very dramatic skies, being most noticeable when the sun sets and clouds redden to what could be described as blood red.

They also established that the direction and location of the scene depicted in The Scream are compatible with the direction and location for nacreous cloud observations.

Going further, the researchers performed detailed analyses of the colors and patterns, comparing the sky and clouds in the painting to photographs of volcanic sunsets and nacreous clouds.

Comparison of sky in (a) 1910 and (b) 1893 versions of The Scream with photographs of (c) nacreous clouds and (d) a volcanic sunset (from journals.ametsoc.org/doi/10.1175/BAMS-D-17-0144.1).

The waviness in the sky in The Scream is absent in the volcanic sunsets, while a uniform progression from red to deep blue seen in volcanic sunsets is absent from the painting. In contrast, The Scream’s alternating patterns of colors and eye-like structure are evident in the nacreous cloud photographs.

Wrap Up
Although The Scream might have been inspired by a particularly striking sunset, a volcanic sunset or simply by Munch’s mental state, the sky depicted in the painting is remarkably similar to that of nacreous clouds.

Reiterating, if Munch did observe then paint his sky with nacreous clouds, The Scream would likely be their first graphical depiction. This would be relevant to atmospheric scientists, particularly to those interested in the historical aspects of the development of cloud science. Thanks for stopping by.

P.S.
Study of the sky in The Scream in Bulletin of the American Meteorological Society: journals.ametsoc.org/doi/10.1175/BAMS-D-17-0144.1
Article on the study on ScienceDaily website: www.sciencedaily.com/releases/2018/07/180723142808.htm
2017 study of The Scream in Royal Meteorological Society’s Weather journal: rmets.onlinelibrary.wiley.com/doi/abs/10.1002/wea.2786
Nacreous clouds (type II polar stratospheric clouds):
www.atoptics.co.uk/highsky/nacr1.htm
weather.com/news/news/ozone-chlorofluorocarbons-cfc-nacreous-clouds-polar-vortex-stratosphere-reaction
en.wikipedia.org/wiki/Polar_stratospheric_cloud
The Scream:
www.edvardmunch.org/link.jsp
en.wikipedia.org/wiki/The_Scream
mymodernmet.com/edvard-munch-the-scream-painting/

A version of this blog post appeared earlier on www.warrensnotice.com.

Bee Foraging

Welcome back. Permit me to begin by recalling an incident that occurred when we were living in Virginia, harboring our absent son Noah’s cat Henry. It was the time Henry leaped onto a radio on a room divider behind my chair in pursuit of a bug on the wall or ceiling. As I faced forward in the chair, the bug flew over my head. Henry followed, jumping from the radio onto the top of my head, where he prepared to launch himself into space after the bug.

There’s more, of course (see Cat and Man--Henry and Me), but today, I’m bypassing Henry in favor of the flying insect.

A Flower-Inspecting Wasp

Canvas print of photograph of
allium on living room wall.

Flying insects somehow find their way into nearly every home. A few weeks ago, a wasp suddenly appeared from nowhere and made a beeline (sorry) to the canvas print of a photograph hanging on our apartment’s living room wall.

The photograph was one my daughter Rachel had taken of an allium plant against a brown wall (see Viewpoints Photo Addendum). She had the photo enlarged and printed on canvas as a gift, and the wasp was carefully inspecting the image of the flower’s petals, pistil and stamen.

Wasp inspecting canvas print of photograph of allium
(photo of wasp by Vicki)

I was fascinated to see a wasp attracted to a photograph of a flowering plant. Perhaps the poor bug was merely confused. The colors the wasp saw were likely quite different from those of the actual plant, even if the flower’s enlarged size made it an obvious target. Yet size of the flowering plant is what I had in mind having just read a recent study about bee foraging.

Flower Size and Bee Foraging
For that study, investigators from Japan’s University of Toyama examined bumble bee (Bombus ignitus) foraging using arrays of nectar-supplying, artificial flowers of different sizes in a laboratory flight cage.

It had generally been assumed that, when bees are exposed to a new area, their foraging efficiency increases as they learn the locations of greater rewards, the higher nectar providers. And that’s what the researchers observed when the test flowers were small (2 centimeters or about 0.8 inch). The bees needed time to find the next closest flower.

When the flowers were large (6 cm or about 2.4 in) and more easily found, however, the bees flew from one flower to the next more quickly. They created foraging routes without accounting for the locations of higher reward flowers.

The results suggest that bees choose rapid rather than accurate foraging when they can locate the flowers easily. The learning of spatial and reward information seems to be a choice that bees and possibly other foragers apply according to a cost-benefit tradeoff.

Wrap up
If you’re wondering about the difference between wasps and bees as it relates to foraging, wasps also have high-energy needs for survival. They need key resources such as pollen and nectar from a variety of flowers, though lacking the fuzzy hairs of bees, they’re less efficient as pollinators.

Now, if you’d like to run your own experiment, Rachel would be very happy to sell you a photograph or canvas print of a photograph of a flower or flowering plant. There are a few examples shown under still life on her website, www.rachelphilipson.com. Thanks for stopping by.

P.S.
Bee forage study in Behavioral Ecology and Sociobiology journal: link.springer.com/article/10.1007%2Fs00265-017-2328-y
Article on study on ScienceDaily website: www.sciencedaily.com/releases/2017/06/170629101711.htm
Examples of older and current research on bee foraging:
booksandjournals.brillonline.com/content/journals/10.1163/156853956x00291
www.benefunder.com/environment-causes/johanne-brunet/understanding-how-bees-foraging-will-improve-plant-and-pollinator-health
Wasp pollination: www.fs.fed.us/wildflowers/pollinators/animals/wasps.shtml

Authenticating Artwork Addendum

Do you know how many ways there are to authenticate a painting? Lots.

Wikipedia would categorize the methods described in last Friday’s blog post, Authenticating Artwork Computationally, as digital authentication. That category encompasses statistical analyses of digital images of paintings and is the newest bundle of authentication methods, borrowed presumably from signal and image processing.

The oldest methods, of course, are examinations by art experts. These methods consider the provenance and every detail of the painting (e.g., brushwork, theme, colors, cracks in older work) as well as observable properties of the canvas or wood, frame, mounting, signature and whatever else might validate or refute the authenticity of the work.

On the shelf between digital and expert analyses, there’s a bag labeled forensic authentication that’s filled with continually evolving scientific methods.

Commonly used imaging methods for examining paintings: infrared reflectography (IRR); visible light (VIS); grazing light obtained with illumination at an oblique angle or almost parallel to the surface (GL); infrared charge coupled device (IR CCD); infrared false color (IRFC); ultraviolet reflectance (UVR); ultraviolet fluorescence (UVF); x-ray radiography (RX). Each method uses wavelengths (measured here in nanometers, nm) that reach different layers of a painting. (www.webexhibits.org/pigments/intro/look.html)

If you reach into the bag, you might grab: radiocarbon dating of canvas and wood; radioactive (radiometric) dating of white lead, one of the most important pigments used especially before the 20th century; x-ray methods (diffraction, fluorescence) to image beneath the visible painting or to analyze the paint’s composition; and in addition to ultraviolet methods (reflectance and fluorescence) to detect surface anomalies and infrared methods for subsurface analysis, other spectroscopic techniques, such as Raman spectroscopy and Fourier transform infrared spectroscopy to identify pigments, binding materials and varnishes and detect anomalies therein.

Forensic Research

A recent study led by an investigator from the Deutsches Elektronen-Synchrotron, Hamburg, who was formerly with the University of Antwerp, Belgium, offers an illustration of non-destructive forensic methods, though it was not conducted to authenticate a painting.

Susanna and the Elders, a 1647 oil on mahogany panel painting by Rembrandt; 30.2 in (76.6 cm) by 36.5 in (92.8 cm). (commons.wikimedia.org/wiki/File:Rembrandt_-_Susanna_and_the_Elders_-_WGA19104.jpg)

The research team set out to compare methods for analyzing subsurface layers of Rembrandt’s Susanna and the Elders to learn the artist’s creative process. The painting has a wide range of pigments of different chemical elements, and x-ray radiography of the painting in the 1930s showed a number of features had been painted over. 

Area of painting shown by different images in the next photograph.

Building on the earlier x-ray radiography, the researchers focused on two imaging methods: neutron activation autoradiography done in 1994 and scanning macro x-ray fluorescence done for the study.

They found the x-ray fluorescence images were easier to interpret. All chemical elements with atomic numbers larger than silicon (14) could be detected; however, the method could only detect bone black, a carbon-based black pigment, on the painting’s surface and would thus miss the artist’s hidden sketches.

Although the neutron activation autoradiography could not resolve inter-element interferences as well, it did differentiate certain pigments (e.g., bone black, umber, copper-based greens and blues, smalt and vermilion). It was also the only method capable of visualizing phosphorus, present in bone black, in lower paint layers. 

Top: Scanning macro x-ray fluorescence images of lead (Pb), copper (Cu) and cobalt (Co); bottom: x-ray radiography (XRR) image from the 1930s and neutron activation autoradiography images (NAAR) done in 1994. The dotted yellow lines in Pb-L trace the original and final positions of the Elder’s arm.

Combining information from the two methods enabled the detection of single brush strokes, an important factor in learning about an artist's technique.

A major operational difference between the two imaging methods is that x-ray fluorescence was performed in situ in a few tens of hours, while autoradiography required weeks in a dedicated research facility.

P.S.

Example articles on art authentication methods:
en.wikipedia.org/wiki/Art_forgery
www.scientiareview.org/pdfs/197.pdf
www.researchgate.net/publication/255709264_A_study_of_uv_fluorescence_emission_of_painting_materials
www.yalescientific.org/2010/12/art-restoration-the-fine-line-between-art-and-science/
fineartconservation.ie/conservation-of-paintings-4-4-32.html
www.heritagesciencejournal.com/content/2/1/13
www.webexhibits.org/pigments/intro/spectroscopy.html
articheck.co.uk/taking-off-the-heat-thermal-quasi-reflectography/

Rembrandt painting study in Applied Physics A: Materials Science and Processing journal and articles on the study on Science Daily and Live Science websites:
link.springer.com/article/10.1007%2Fs00339-015-9081-8
www.sciencedaily.com/releases/2015/04/150414085319.htm
www.livescience.com/50497-rembrandt-painting-hidden-layers.html

Authenticating Artwork Computationally

Welcome back. During our latest swing through New York and Virginia, we visited with my daughter Rachel and son-in-law Mike. He’s an abstract painter. I’ve featured his work in a blog post (Abstract Memories Photo Addendum) and his websites are on the Blog Watch List (Mike’s Paintings, Dunham Enfield Art).

I mention this, not only so you’ll view and purchase his paintings, but because he and I spoke briefly about analyzing artwork--not as an art lover or critic, but from the standpoint of who really painted that painting? I had seen a recent study that used machine vision to authenticate Jackson Pollock’s paintings, and Mike was interested in learning more about it.

Pollock’s Painting Technique

Jackson Pollock action painting with his
all-over style, watched by spouse Lena
(Lee) Krasner, who was also a celebrated
abstract expressionist painter.
(Multiple websites)

Jackson Pollack (1912-56) was the leading figure of the art world’s Abstract Expressionist movement that followed World War II. Best known for his action painting technique, he would drip, splash and pour paint onto the canvas, placed on the floor or against a wall, manipulate the paint with knives, trowels or sticks rather than soft brushes and sometimes add sand or other material for depth.

Pollock also led the all-over style of painting, which shuns any clear point of emphasis on the canvas, such as the face of a person sitting for a portrait. The all-over painting style gives equal attention to all parts of the composition, independent of the canvas size; it invites the viewer to roam, following colors, lines and shapes.

His unique artistic style was emulated by others, resulting in many fake and disputed “Pollocks.”

Fractal Analysis of Pollock’s Paintings

Background for the latest study is provided by a 1999 analysis of Pollock’s paintings by researchers from Australia’s University of New South Wales. They showed that the patterns were fractal. A fractal is a never-ending pattern, infinitely complex, that has the same structure (is self-similar) at different scales. 

Jackson Pollock’s Blue Poles, originally titled Number 11; enamel and aluminum paint with glass on canvas, approx. 7 feet by 16 feet; painted 1952; owned by National Gallery of Australia since 1973. (Video on Blue Poles and Pollock: www.youtube.com/watch?v=fnORitT5h4U)

Though we can easily measure the dimensions of a line, rectangle or cube, we have a harder time with complex objects, the classic example for fractals being the length of the coastline of Great Britain. Fractal dimension allows measurement of the degree of complexity of an object by evaluating how fast the measurements increase or decrease as the scale changes.

I’ll pass on describing the algorithms but note that there are different types of fractal dimension, the most commonly used being self-similarity and box-counting. The 1999 analysis of Pollock’s paintings used the latter, dividing images of his paintings into boxes of different sizes and recording the fraction of boxes containing part of the painted pattern as the basis of the fractal dimension.

While the 1999 study concluded that fractal analysis could be applied to characterize and authenticate Pollock’s paintings, later work by researchers from Case Western Reserve and Arizona State universities questioned that conclusion. Later still, investigators at Ricoh Innovations showed that the fractal feature could indeed be useful when combined in a classifier that employed multiple image descriptors.

Latest Research

Which brings me to the study that I spoke about with Mike. The researcher, from Lawrence Technological University, scanned 26 paintings by Pollock and paintings by others who tried to mimic Pollock’s style, extracting over 4000 numerical image descriptors from each painting. Comparing them computationally, he found the image descriptors were able to differentiate Pollock’s paintings with an accuracy of 93%.

Fractal features were the most discriminating image descriptor but other descriptors showed substantial differences (e.g., Zernike polynomials, Haralick textures and Chebyshev statistics).

Wrap Up

Pollock’s painting style was truly unique. It may not be fully distinguished with fractals or any single mathematical descriptor, but when different image descriptors are combined, his paintings are computationally separable from those by other artists who would try to copy his work.

And if computational approaches to detecting art forgery seem a bit much, you and of course Mike know from movies and television that there are other ways to authenticate a painting. I’ll highlight some of those in next Tuesday’s blog post. Thanks for stopping by.

P.S.

Background articles on Jackson Pollock:
www.jackson-pollock.org/index.jsp
www.ibiblio.org/wm/paint/auth/pollock/
www.moma.org/cef/abex/html/know_more9.html
Video on Pollock’s action-painting, all-over style:
www.khanacademy.org/partner-content/MoMA/moma-abstract-expressionism/v/moma-painting-technique-pollock
Background articles on fractals:
fractalfoundation.org/resources/what-are-fractals/
en.wikipedia.org/wiki/Fractal
University of New South Wales study in Nature journal and article on study:
www.nature.com/natur20e/journal/v399/n6735/full/399422a0.html (must paste link into browser)
materialscience.uoregon.edu/taylor/art/Nature1.pdf
Case Western Reserve and Arizona State universities study in Physical Review E journal: www.phys.cwru.edu/faculty/papers/mathur/prefractal.pdf
Ricoh Innovations report in SPIE: spie.org/x35260.xml
Lawrence Technological University study in the International Journal of Arts and Technology and article on study on Science Daily website:
www.inderscience.com/offer.php?id=67389
www.sciencedaily.com/releases/2015/02/150210133210.htm

Faces from DNA Addendum

Searching research reports for last Friday’s blog post, Faces from DNA, I happened upon Heather Dewey-Hagborg’s bio-art project, Stranger Visions, and was blown away.  

Heather Dewey-Hagborg’s DNA-derived 3D-printed portraits at New York City’s Clockwork Tower Gallery exhibit, 2013. (clocktower.org/residency/heather-dewey-hagborg-stranger-visions)

Dewey-Hagborg is an assistant professor of Art and Technology Studies at the School of the Art Institute of Chicago whose artwork has been exhibited internationally. She is also pursuing a PhD in Electronic Arts at Rensselaer Polytechnic Institute.

A face predicted by Dewey-Hagborg
from DNA extracted from a cigarette
 butt found on a sidewalk.
(deweyhagborg.com/strangervisions/portraits.html)

Stranger Visions is a series of 3D facial portraits she created from DNA she recovered from cigarette butts, chewed gum and other discarded items. Really!

The discarded cigarette butt from
which Dewey-Hagborg extracted
the DNA that led to the face.
(deweyhagborg.com/strangervisions/portraits.html)

To develop her project, she took a 3 week course in biotechnology, extracted the DNA from her samples, processed parts of the genome to facilitate identification of SNPs (see Friday’s post) and sent the results to a company for sequencing.

She input the genetic code she received from the company into a computer program she had written to produce a list of traits, such as gender and color of eyes and hair. Finally, she used a face-generating program she had modified from a facial recognition program to prepare 3D portraits from which she made her final 3D prints.

The location in Brooklyn, N.Y., where Dewey-Hagborg found the discarded cigarette butt. (deweyhagborg.com/strangervisions/portraits.html)

How does Dewey-Hagborg’s DNA-face prediction method differ from that of the researchers and private company described last Friday? I haven’t the foggiest idea. I would expect that her faces, generated and massaged for art, do not depict their source as accurately, but the general approaches seem similar.

One difference is certainly found in the theme behind Stranger Visions--privacy, how much information can be derived from your DNA and the potential for a culture of genetic surveillance.

P.S.

-An article on Live Science website alerted me to Heather Dewey-Hagborg’s Stranger Visions: www.livescience.com/50146-art-genetic-data-privacy.html
-Wikipedia provided descriptions of Dewey-Hagborg and Stranger Visions: en.wikipedia.org/wiki/Heather_Dewey-Hagborg
-One of Wikipedia’s references provided the Stranger Visions portraits: deweyhagborg.com/strangervisions/portraits.html
-The Live Science article led me to exhibit announcements by Clocktower Gallery in New York City (2013) and South by Southwest (SXSW) Interactive in Austin, Texas (2015):
clocktower.org/residency/heather-dewey-hagborg-stranger-visions
schedule.sxsw.com/2015/events/event_IAP40120
-Dewey-Hagborg developed Stranger Visions at Genspace, a non-profit, community-based organization in New York City that provides training and mentoring in biotechnology: genspace.org/
-DNA sequencing for Stranger Visions was done by 23andMe, a privately held personal genomics and biotechnology company: www.23andme.com/

Fragmentation Addendum

I’ve gone about as far as I should go with Habitat Fragmentation, discussed last Friday, but you’ll find fragmentation or fragments popping up elsewhere.

Another example from science is the process by which certain lower plants and animals break into two or more fragments that grow into complete individuals. Although planaria, the free-living flatworms that reside in quiet bodies of water, probably don’t get very titillated by fragmentation, as asexual reproduction goes, it’s pretty cool.

Fragmentation in planaria. (www.tutorvista.com/content/biology/biology-ii/reproduction/asexual-reproduction.php#fragmentation)

Shifting from science to engineering, you’ll find fragmentation referring to inefficient computer storage that reduces the computer’s capacity or performance, or both. More commonly, you’ll read that you should periodically defragment or consolidate the files on your hard drive to make your computer hum with happiness.

Estimated hard disk usage before and after defragmentation, top vs. bottom bar. (Multiple websites.)

If you venture into military engineering and antipersonnel weapons, you’ll quickly come across fragmentation, which is nothing to joke about.

M67 fragmentation hand grenade. (Multiple websites)

Take a break, watch a movie. I’ve sat through many I thought were fragmented, yet there’s at least one titled Fragments. The R-rated movie, released in 2008 or 2009, was based on a book, Winged Creatures, and also went by the book’s name. It’s a story about strangers forming a unique relationship after surviving a random shooting at a Los Angeles diner.

Poster for movie Fragments, also called Winged Creatures. (Multiple websites, www.imdb.com/title/tt0948547/)

If you’d prefer to read rather than watch a movie, you’ll find books titled Fragments. No doubt the one with the most attractive front cover is a collection of poems, notes and letters by Marilyn Monroe. The hardcover version was published by Farrar, Straus and Giroux in 2010.

Marilyn Monroe’s book, Fragments, published in 2010. (Multiple websites)

Sticking with the arts, you’ll find fragmentation in music composition and photography as well as in other art forms. Wikipedia offers that postmodern art eradicates the boundaries between high and low art forms, disrupting conventions with collision, collage and fragmentation.

Fragmented Art by boxdemon (www.thatcreativefeeling.com/fragmentation-deconstruction-art/)

Finally, if you sometimes feel your life is fragmented, just think of countries like the Philippines with over 7100 islands or states that need a bridge to hold it together.

The Mackinac Bridge connects the Upper and Lower peninsulas of the fragmented state of Michigan. (Multiple websites; www.maps.com)

Deferred Guidance

Welcome back. Last Saturday, while stretching the washed and dried sheets back onto our bed, I began wondering what else I’d have to learn at my advanced age. I don’t mean learn for my cognitive development or for this blog. I learn something new every time I research topics. No, I was wondering about little things I’d missed over the years, like which side of the top bed sheet should face up.

Here’s the thing. I’ve always been our family’s laundry person, yet I wasn’t aware there was a proper order to bed sheet placement. I can only guess the odds that I’ve put the top bed sheet face up or down over the past 30 or so years are close to 50-50.

I could live with that. Well, I could if my wife Vicki hadn’t informed me about a year ago that the top bed sheet should face down, not up. Her decree prompted two concerns.

First Concern: Bed Sheets

A bed sheet corner exposing
the side which must face up
when making the bed.

Most immediately, what did she mean by face down or, for that matter, face up? I resolved that through careful study of the bed sheet: the flowers were more distinct on one side and the hem, or whatever it’s called, was folded to the other side. I knew I’d found the face.

I neither doubted nor cared if Vicki was correct or questioned why it mattered; I just proceeded to follow her directions. For the purpose of this blog post, however, I knew you’d expect me to research the topic.

I won’t burden you with numerous references. Trust me. The overwhelming opinion is that, if the top of the top sheet appears, anyone who happens to be passing by should see its face. That can only happen if, when making the bed and folding the top of the top sheet over our duvet, I install the top sheet face down on the bed.

Second Concern: Art Appreciation

The second concern induced by Vicki’s bed sheet bulletin was what else was I doing wrong?

I should have anticipated something like this was coming. A few years earlier in our previous home, Vicki announced that she thought the painting that had hung for 14 years next to our front door, where anyone departing would see it, was dark, depressing and dreadful.

Her painting confession was probably more piercing than her bed sheet pronouncement. I would not have hung the painting, which I’d purchased in my dark, depressing distant past, without her explicit approval.

We quickly replaced the painting with one of my daughter Rachel’s photographs--a bright sunflower that would cheer anyone departing, even a departee who was sad to leave.

Since Vicki loves Rachel’s photography, I felt confident I wouldn’t be surprised in 14 years. That confidence, however, did not extend to my photographs, a handful of which were hung along the entry corridor. Despite her assurances to the contrary, I had my doubts.

Rachel’s photographs on a wall in our
current apartment. (Sunflower on left.)

Those suspicions were confirmed on moving to our present abode, where Vicki chose and hung the artwork before I arrived. There are ample examples of Rachel’s work, including the sunflower, but none of mine.

Wrap Up

Of course there’s no reason to be totally honest about everything in a marriage. It isn’t pick your battles, as you might have to adopt with your kids. It’s more like being encouraging and thinking we’ll be together a long time, why rush to judgement. Vicki excels at that, especially over small stuff like bed sheets and wall hangings. I’m still working on it.

Thanks for stopping by. And that’s the truth!

Finger Painting Addendum

Pondering an extension of last Friday’s post, Finger Length Ratio, I thought you’d welcome something more, well, colorful. That led me to finger painting. Since my recollection of the topic was limited to artwork hung prominently on our refrigerator when my offspring were in elementary school, my reaction to what I found was WOW!

Before justifying my reaction, I’d better mention that Ruth Faison Shaw introduced finger painting to art education and, in 1931, patented a non-toxic, gelatinous paint that would be safe for children. Adults decided to try it out, and they--finger painting artists--moved on to donning surgical gloves so they could finger paint with oils, acrylics, soft pastels and just about anything in addition to Ms. Shaw’s finger paint.

Zaria Forman’s finger painting, “Greenland #66,” on view at the American Embassy in Switzerland through 2017. Soft pastel on paper. (From www.zariaforman.com/; video of artist’s work:
www.youtube.com/watch?v=aQv_VrMYHRw)

Iris Scott’s finger painting, “Shakin' off the Blues,” paper print of original oil (From twistedsifter.com/2014/06/fine-art-finger-paintings-by-iris-scott/; artist’s website: www.irisscottfineart.com/)

Dennis Velco’s finger painting, “Poppies and Their Buds,” acrylic paint on canvas. (From www.dennisvelco.com/; 1st of 22 videos of artist at work: www.youtube.com/watch?v=nvUbSvUuens&index=4&list=PL64590AA4B7BDD3AF)

The late Jimmie Lee Sudduth’s folk art, finger painting, “The Grimsley House with Tree,” mud and paint on wood. (From www.marciaweberartobjects.com/sudduth.html)

Chuck Close’s “Fanny/Fingerpainting,” oil on canvas, which earlier hung in Smithsonian’s National Gallery of Art. (From www.mymodernmet.com/profiles/blogs/chuck-close-fanny-fingerpainting; www.nga.gov/content/ngaweb/Collection/art-object-page.69637.html)

Paolo Troilo’s finger painting “Carnival #3,” acrylic on canvas. (From www.troilo54.com/; video of the artist describing his work: www.youtube.com/watch?v=sM5W8ntRPxc)

Hanging scroll "Finger Painting of Eagle and Pine Trees" by Gao Qipei (1660-1734), Shanghai Museum. (From commons.wikimedia.org/wiki/File:GaoQipei-FingerPaintingOfEagleAndPineTrees-ShanghaiMuseum-May27-08.jpg)

I’ll end with this painting, because I like it and the strokes and smears are how I remember finger painting. (Painter unknown; from synergysm.com/wpcontent/uploads/2014/05/Fingerpainting_Poster.jpg)

P.S.

Background: en.wikipedia.org/wiki/Fingerpaint
Examples of other artists whose work is not shown here:
www.fingerpainter.com/
yolandasanchezstudio.com/paintings