Painters have used different types of mediums for centuries. There is oil, watercolor, acrylic, and tempera paint. One thing each of these paints have in common is the fact that each of their colors come from pigments. Pigments are usually minerals that are ground up and mixed with different binders to create paint. One medium whose popularity has risen and fallen through the ages is tempera paint. Created with pigment and a mixture of egg and water or casein (protein from milk) tempera paint has been a convenient medium used by artists for years.
Pigments are the properties in paint that give them their color. Pigments are various elements. These elements absorb and give off light, which humans then perceive as a number of colors. Different elements give off different colors. For example, the pigment “Cobalt green” is created when one gram of cobalt(II) chloride and five grams of zinc(II) oxide are mixed together and heated. The pigment that is then created gives off a dark green color. Pigments for paint are found it a ground substance very similar to thick sand. Not only made in sand form, during the Renaissance era pigments were dug out of the ground and shaped into chalk. In recent years, pigments have begun to be artificially created. One thing most people do not know is that pigments have different toxicity levels. The pigment “Emerald green” is very rare. It was created in 1808 as a replacement for Scheele’s green. This pigment was often used in paint as a color for houses but then found to be too toxic for use and was discontinued in the 1960s for causing deaths.
Tempera paint has been used for centuries starting in the Paleolithic ages. At that time they came from natural sources and were mixed with spit or fat from animals to create paint that was then used to paint caves. Later, in the twelfth century a monk used casein tempera paint. Casein paint has a casein binder. Casein is protein from milk. This was used for sometime then it’s popularity fell. Then, in the fourteenth century egg tempera was the primary medium for Italian artists. Many colors that were used are not in use today. One example of this is the color ‘Azurite’. It was one of the most prominent colors in artwork of the Middle Ages and during the Renaissance but was replaced when the color ‘Prussian blue’ was discovered. In the sixteenth century the popularity of egg tempera died down. In the late ninetieth and twentieth centuries artists began to study works of art and, wanting the same feel and look, began to use egg tempera again.
Binders are the item used in paint to make it stick to a canvas. The reason that this works is because most binders are something called a polymer. Binders can be many things including the protein from milk, fat, oil, or egg. Recently, there was a study conducted in which scientists created egg tempera paint the same as they did during the Renaissance era. They found that when applied to a canvas of some sort, these paints have certain properties (like the presence of lipids, proteins, and carbohydrates), which helped the paint stick to the canvas better. One example of how well an egg can work as a binder is simply found from doing dishes. Have you ever tried to wash your plate after having an egg for breakfast and find that it is a bit difficult to wash off? This is because egg sticks well and dries fast making it an ideal binder for paint.
When comparing tempera paint to oil paint one can see the differences very quickly. While oil paint is thicker while egg tempera tends to be much thinner. Oil paint dries very slowly and tends to look a bit murkier because artists often would mix the paints together while they dried. Egg tempera is known for being very vibrant and having a luminescent quality. With egg tempera you have to apply multiple layers. The good thing about this, however, is the speed at which egg tempera dries making this process go relatively quickly.
Pigments have been used for centuries and not only are good for paint but also different mediums of art such as chalk. Also, they are made up of different elements. Tempera paint is a popular medium and is convenient to make and use. Binders are what helps the pigments stay to a canvas and what, essentially, makes paint paint. There are perks and flaws to both tempera paint and oil paint but both are good for different styles of painting. Overall, tempera paints are a good choice of medium and have been shown to be so throughout the ages.
Tuesday, February 24, 2009
Sunday, February 22, 2009
Uncle Tungsten
Uncle Tungsten Chapters 21-25
Chapter 21:
1) What is pitchblende?
Pitchblende is the element also known as uraninite. It is called this because of it’s mixture of other metals (such as lead and thorium) and the fact that it is very dark. It can be up to four times as radioactive as uraninite or thorium.
2) Describe the process used by the Curie's to separate the elements in pitchblende.
They first broke it down into groups and continued to brake it down until they came about a new element which they suggested be called polonium.
3) Why did the Curie's die so young?
Both the Curies worked with very radioactive materials and did not think about the effects that the radioactivity could have on them.
Chapter 22:
1) What is Sack's idea for a vanadium farm?
He would want to have many acres of sea meadows with sea squirts in it and then collect vanadium from the sea meadows.
2) What is the Milton society and what happened to it?
The Milton Society was a literature group at Sack’s school. It was unpopular and many knew it wouldn’t last.
Chapter 23:
1) What is the half-life of an element?
It is the characteristics of a radioactive element that is transforming.
2) How did the understanding of elemental decay affect the debate over the age of the earth?
Because many thought that the earth was too cold to sustain life before a certain time.
3) Why did the bombing of Hiroshima remind Sacks of Soddy and Wells?
Sacks thought of Soddy and Wells when hearing of Hiroshima because they were two large figures in nuclear power.
Chapter 24:
1) How did Moseley confirm the periodic table?
He used a cathode ray to get x-rays of each of the elements and then plotted the square roots of the elements against their atomic weight. This way, nothing could be missing or added.
2) How do electrons determine the elements chemical properties?
The electrons create bonding and therefore making up the chemical bonding.
3) How did Bohr's elemental periodic table compare with Mendelev's empirical periodic table?
They are almost the same. They both rely heavily on numbers for organization.
Chapter 25:
1) How and why did the affair with metals and their chemistry come to an end in Oliver Sack's life?
It didn’t happen suddenly, but he knew that one day he would have to go to medical school and become a doctor and his interest in chemistry slowly died out.
Chapter 21:
1) What is pitchblende?
Pitchblende is the element also known as uraninite. It is called this because of it’s mixture of other metals (such as lead and thorium) and the fact that it is very dark. It can be up to four times as radioactive as uraninite or thorium.
2) Describe the process used by the Curie's to separate the elements in pitchblende.
They first broke it down into groups and continued to brake it down until they came about a new element which they suggested be called polonium.
3) Why did the Curie's die so young?
Both the Curies worked with very radioactive materials and did not think about the effects that the radioactivity could have on them.
Chapter 22:
1) What is Sack's idea for a vanadium farm?
He would want to have many acres of sea meadows with sea squirts in it and then collect vanadium from the sea meadows.
2) What is the Milton society and what happened to it?
The Milton Society was a literature group at Sack’s school. It was unpopular and many knew it wouldn’t last.
Chapter 23:
1) What is the half-life of an element?
It is the characteristics of a radioactive element that is transforming.
2) How did the understanding of elemental decay affect the debate over the age of the earth?
Because many thought that the earth was too cold to sustain life before a certain time.
3) Why did the bombing of Hiroshima remind Sacks of Soddy and Wells?
Sacks thought of Soddy and Wells when hearing of Hiroshima because they were two large figures in nuclear power.
Chapter 24:
1) How did Moseley confirm the periodic table?
He used a cathode ray to get x-rays of each of the elements and then plotted the square roots of the elements against their atomic weight. This way, nothing could be missing or added.
2) How do electrons determine the elements chemical properties?
The electrons create bonding and therefore making up the chemical bonding.
3) How did Bohr's elemental periodic table compare with Mendelev's empirical periodic table?
They are almost the same. They both rely heavily on numbers for organization.
Chapter 25:
1) How and why did the affair with metals and their chemistry come to an end in Oliver Sack's life?
It didn’t happen suddenly, but he knew that one day he would have to go to medical school and become a doctor and his interest in chemistry slowly died out.
Outline
Pigments and Tempera Paints Outline
What’s That Stuff? Tempera Paint & Pigments
I. Introduction:
-Artists have used all different types of mediums for centuries. There’s charcoal, oil paint, even photography. One medium that’s popularity has gone in and out through the ages, however, is tempera paint. Created with pigments and a mixture of egg and water or casein tempera paint has been a convenient medium used by artists for years.
II. Chemistry of Pigments
-Pigments are perceived as different colors
-Elements absorb lights that have color and let off another color
-Different elements create different colors
-For example, the pigment “Cobalt green” is created when one gram of cobalt(II) chloride and five grams of zinc(II) oxide are mixed together and heated
-The color “Emerald green” was created in 1808 but then found to be too toxic for use and was discontinued in the 1960s for causing deaths.
III. History
-Pigments have been used for centuries starting in the Paleolithic ages.
-Pigments at that time came from natural sources and mixed with spit or fat
-A monk in the 12th century used casein tempera paint
-Egg tempera was the primary medium for Italian artists in the 14th century
-Pigments were not only mixed for paint but also used as chalk
-In recent years pigments have began to be artificially created
-In 16th century popularity of egg tempera died down as pigment mixed
with oil became more popular
-In late 19th and 20th centuries artists studied paintings of the past and egg tempera regained its popularity
-
IV. Binders
-Binders are used in paint to make the pigment stick to your canvas.
-This works because most binders are something called a polymer.
-Binders can be many things including milk, fat, oil or egg.
-Have you ever tried to wash your plate after having an egg for breakfast and find that it is a bit difficult to wash off? This is because egg sticks well and dries fast making it an ideal binder for paint.
-
V. Tempera Paint vs. Oil
-Tempera paints are thinner then paints such as oil
-Multiple layers must be applied
-Egg tempera dries very quickly therefore layers can be applied one right after another
-Oil, however takes much longer to dry and sometimes artwork using oil paint is murkier then the bright and luminescent quality egg tempera paintings come up with
What’s That Stuff? Tempera Paint & Pigments
I. Introduction:
-Artists have used all different types of mediums for centuries. There’s charcoal, oil paint, even photography. One medium that’s popularity has gone in and out through the ages, however, is tempera paint. Created with pigments and a mixture of egg and water or casein tempera paint has been a convenient medium used by artists for years.
II. Chemistry of Pigments
-Pigments are perceived as different colors
-Elements absorb lights that have color and let off another color
-Different elements create different colors
-For example, the pigment “Cobalt green” is created when one gram of cobalt(II) chloride and five grams of zinc(II) oxide are mixed together and heated
-The color “Emerald green” was created in 1808 but then found to be too toxic for use and was discontinued in the 1960s for causing deaths.
III. History
-Pigments have been used for centuries starting in the Paleolithic ages.
-Pigments at that time came from natural sources and mixed with spit or fat
-A monk in the 12th century used casein tempera paint
-Egg tempera was the primary medium for Italian artists in the 14th century
-Pigments were not only mixed for paint but also used as chalk
-In recent years pigments have began to be artificially created
-In 16th century popularity of egg tempera died down as pigment mixed
with oil became more popular
-In late 19th and 20th centuries artists studied paintings of the past and egg tempera regained its popularity
-
IV. Binders
-Binders are used in paint to make the pigment stick to your canvas.
-This works because most binders are something called a polymer.
-Binders can be many things including milk, fat, oil or egg.
-Have you ever tried to wash your plate after having an egg for breakfast and find that it is a bit difficult to wash off? This is because egg sticks well and dries fast making it an ideal binder for paint.
-
V. Tempera Paint vs. Oil
-Tempera paints are thinner then paints such as oil
-Multiple layers must be applied
-Egg tempera dries very quickly therefore layers can be applied one right after another
-Oil, however takes much longer to dry and sometimes artwork using oil paint is murkier then the bright and luminescent quality egg tempera paintings come up with
Friday, February 20, 2009
Pigments & Tempera Paints Sources
http://homerepair.about.com/od/termsor/g/Pigment.htm
http://studiochalkboard.evansville.edu/p-pigment.html
http://www.watercolorpainting.com/eggtempera.htm
http://www.eggtempera.com/index.html
http://www.danielsmith.com/Learn/Articles/Making-Egg-Tempera.asp
http://www.eggtempera.org/
http://www.owlpen.com/paintedclothsessay.shtml
http://www.lindapaul.com/about_egg_tempera.htm
http://www.webexhibits.org/pigments/
http://www.brandywinemuseum.org/news_print/news058_print.html
http://www.learn-to-draw-and-paint.com/casein.html
http://www.springerlink.com/content/2707l65312430724/
http://www.paleolithic.com/
http://www.temperaworkshop.com/technique/technique4.htm
http://studiochalkboard.evansville.edu/p-pigment.html
http://www.watercolorpainting.com/eggtempera.htm
http://www.eggtempera.com/index.html
http://www.danielsmith.com/Learn/Articles/Making-Egg-Tempera.asp
http://www.eggtempera.org/
http://www.owlpen.com/paintedclothsessay.shtml
http://www.lindapaul.com/about_egg_tempera.htm
http://www.webexhibits.org/pigments/
http://www.brandywinemuseum.org/news_print/news058_print.html
http://www.learn-to-draw-and-paint.com/casein.html
http://www.springerlink.com/content/2707l65312430724/
http://www.paleolithic.com/
http://www.temperaworkshop.com/technique/technique4.htm
Tuesday, September 2, 2008
Homeland Security's Research Facility
Huffington Post
Although a research facility sounds like an amazing idea, why is it that Homeland Security would be the people in charge of it? This article confused me. I think that if the DHS is pushing so much to have the facility somewhere, and there are people that have the power to put it somewhere better, they should put it in a better place. I think that when you look at all the things that have gone bad with Homeland Security, how can you trust them to be studying these things? I mean, aren't these the people with the wait until something goes wrong and then fix it mentality? I guess all we can really do as far as changing all the things that the DHS does wrong, is wait for a new administration. Which is a somewhat scary thought because you never know how wrong things could go in that short amount of time.
Questions that arouse while reading this article:
1. I'm still very confused as to why the DHS wanted the research center in Mississippi so badly. Why is this?
2. Who would they hire to do the research at this center?
3. What would they/we do with the information gathered at this new facility?
Monday, September 1, 2008
Homeland Security Watching Our Phone Calls
Brookings Institution
It was reported by USA Today that many phone companies have given away their phone numbers to the National Security Agency in effort to help stop terrorism. While I understand that this is an attempt to keep us safe, is losing our privacy worth it? Plus, not everything works out as planned. So many different things are misinterpreted and misread. I don't think that this is such a good idea. Having someone constantly watching what you are doing, who you are calling, it's violating our constitutional rights as citizens of the United States. Of course, when many doubt the fact that the president has even read the Constitution, you can't really expect your rights to be respected. Homeland Security is obviously there for a reason, but are they really doing a good job at what they are supposed to be doing? Or has someone given them too much power?
Questions:
1. Even though President Bush has let them have the numbers, and the phone companies have given them the numbers willfully, can they be prosecuted for this?
2. Once the presidential office is taken over by someone else, will they be able to do anything about this? I mean, it's not exactly Homeland Security's fault, they were just following orders, and I hardly think they would punish Bush for this.
3. This was a very hot topic for a while, but it seems like the interest is dwindling. Why is it that people aren't more concerned still? It's still happening, but have they given up trying to stop it?
It was reported by USA Today that many phone companies have given away their phone numbers to the National Security Agency in effort to help stop terrorism. While I understand that this is an attempt to keep us safe, is losing our privacy worth it? Plus, not everything works out as planned. So many different things are misinterpreted and misread. I don't think that this is such a good idea. Having someone constantly watching what you are doing, who you are calling, it's violating our constitutional rights as citizens of the United States. Of course, when many doubt the fact that the president has even read the Constitution, you can't really expect your rights to be respected. Homeland Security is obviously there for a reason, but are they really doing a good job at what they are supposed to be doing? Or has someone given them too much power?
Questions:
1. Even though President Bush has let them have the numbers, and the phone companies have given them the numbers willfully, can they be prosecuted for this?
2. Once the presidential office is taken over by someone else, will they be able to do anything about this? I mean, it's not exactly Homeland Security's fault, they were just following orders, and I hardly think they would punish Bush for this.
3. This was a very hot topic for a while, but it seems like the interest is dwindling. Why is it that people aren't more concerned still? It's still happening, but have they given up trying to stop it?
Friday, August 29, 2008
Homeland Security's Struggle
The Washington Post
Although the article I read about Homeland Security's problems seemed a little like an excuse for how they are run, I found it interesting. Not only does the chief of Homeland Security admit to waiting for a problem to occur to fix it, he says that he does it because of the people he is working for. Does the blame really belong solely on the Bush Administration? They were the ones that created Homeland Security to secure our country. The Bush Administration is flakey at the best of times, but when they are putting the safety of our country on the shoulders of someone like Homeland Security can they really expect it to fall apart? I mean, they are the ones who created it.
Questions that came up while and after reading this article:
1. If Homeland Security was created by and for the Bush Administration, will the next administration get rid of it?
2. The article mentioned that the working conditions over at Homeland Security were very poor ones. Doesn't any department working for the government automatically get the best? And if they don't what other departments are doing nothing to help our country?
Although the article I read about Homeland Security's problems seemed a little like an excuse for how they are run, I found it interesting. Not only does the chief of Homeland Security admit to waiting for a problem to occur to fix it, he says that he does it because of the people he is working for. Does the blame really belong solely on the Bush Administration? They were the ones that created Homeland Security to secure our country. The Bush Administration is flakey at the best of times, but when they are putting the safety of our country on the shoulders of someone like Homeland Security can they really expect it to fall apart? I mean, they are the ones who created it.
Questions that came up while and after reading this article:
1. If Homeland Security was created by and for the Bush Administration, will the next administration get rid of it?
2. The article mentioned that the working conditions over at Homeland Security were very poor ones. Doesn't any department working for the government automatically get the best? And if they don't what other departments are doing nothing to help our country?
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