Inkjet Printing

Posted by PITHOCRATES - March 5th, 2014

Technology 101

A Sunday Afternoon on the Island of La Grande Jatte is similar to Ink Jet Printing

Stephen Sondheim and James Lapine created a musical based on the painting A Sunday Afternoon on the Island of La Grande Jatte by Georges Seurat.  Giving us Sunday in the Park with George.  Seurat used a technique called pointillism.  Where he painted dots of color.  Points.  Up close the eye saw only a mass of different colored dots.  But when you moved back from the painting the brain blended those dots together into an image.

This is the same technique our televisions use to recreate an image on the screen.  Using only the 3 primary colors of light.  Red, blue and green.  Different colors of phosphor are energized to glow.  Causing a combination of these three dots of phosphor to glow creates a pixel of color.  A screen full of different colored pixels creates an image.  It’s similar to inkjet printing.  Where a print head places dots of different colors on a piece of paper.  Much like George did in Sunday in the park with George.  Although an inkjet printer can do it faster.  And without destroying a relationship.

George painted one dot at a time.  So it took him a very long time to create an image.  —SPOILER ALERT—   So much time that Dot left him and had a baby with Louis the baker.  Leaving George alone.  A true suffering artist.  Who died young.  Never realizing that Dot’s baby was his.  Which gave us a second act.  A great musical.  With some of Sondheim’s best music and lyrics.  The original Broadway recording with Mandy Patinkin and Bernadette Peters should be in everyone’s collection.  Do yourself a favor and buy it.  Support the arts.  But I digress.

Droplets of Ink are shot out of the Print Head onto the Paper without any Physical Contact with the Paper

If you have a large art museum near where you live you can probably see a work of art done in the pointilism technique up close.  And if you do you’ll probably notice that the dots are rather big.  Unlike they are with an inkjet printer.  Where the dots are much smaller.  It’s the same technique.  Pointillism.  But it is much harder to see that with inkjet printing.  Why?

George painted with a paint brush.  And even when the bristles are smoothed into a point it’s still pretty thick.  And makes large dots.  An inkjet, on the other hand, doesn’t ‘brush’ on the ink.  It spits it on.  Droplets of ink are shot out of the print head, across an air-gap and onto the paper.  Without any physical contact.  The only physical contact with the paper is the roller that loads a sheet.  And the roller that advances the sheet.  While the print head glides above the paper.  Spitting droplets of ink.

Well, it doesn’t actually spit ink.  It boils it.  In the ink cartridge.  Which is a marvel of engineering.  For the ink cartridge not only contains the ink.  But it also contains the print head.  A few hundred holes where droplets of ink jet out of.  As well as a lot of copper etched circuits.  To take the information from the computer when printing a document.  And transferring it to the proper ink port.  Which are very, very tiny holes.  So tiny that the droplets they produce make for near photo-like quality compared to a pointillism painting.

The Ideal Gas Law tells us if we incrase the Temperature while holding the Volume Constant the Pressure Increases

The ideal gas law is PV = nRT.  Which can be solved such that P = nRT/V.  Where pressure (P) equals the chemical amount in moles (n) times the universal gas constant (R) times the temperature (T) divided by the volume (V).  A lot of information there.  But the only things we want to focus on are pressure, temperature and volume.  The ideal gas law tells us if we incrase the temperature while holding the volume constant the pressure increases.  Which is how inkjet printing works.

Each ink port has ink in it.  But the hole is so tiny that the ink in its normal state will not flow through it.  Because it’s too thick.  However, when you heat the ink to boil it into a vapor the pressure is so great that it pushes a droplet of ink out of the print head onto the paper to releive the pressure.  All of this happens in a fraction of a second in all of those hundreds of ink ports.  An electric circuit turns on.  Boils ink.  Forces out a droplet.  The electric circuit shusts off.  And the ink just used to print with is replaced with fresh ink.  Waiting for the next electric current to boil it.

Complex software and hardware to advance the paper and move the print head over the paper are all coordinated to place thousands of droplets of ink with each pass of the print head.  A black ink cartridge is used for text documents.  And a color ink cartridge (red, blue and yellow) is used to add color to a text document.  Or to print color images.  Doing the work of a thousand Georges.  Faster.  And with tinier dots.  So tiny that they are impossible to detect with the naked eye.  Unlike Seurat’s A Sunday Afternoon on the Island of La Grande Jatte.  But few printed items will look as good.

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Visible Light, Additive Coloring, Subtractive Coloring, Printing and Pointilism

Posted by PITHOCRATES - August 28th, 2013

Technology 101

Our Eyes see Shades of Gray with Rods and Color with Cones

If you have colorful flower gardens all around your home and go out at night you won’t see much.  Only shades of gray.  You’ll see none of the vibrant colors of your flowers.  The moonlight, streetlights, the neighbor’s security lights, your landscaping lights, etc., will provide enough lighting so you can see your flowers.  But you won’t be able to see their colors well.  If at all.

If you go out with the bright afternoon sun shining down it’s a different story.  You can see the color.  Rich, vibrant color.  Because of the cones in your eyes.  Which can see color.  As long as it is bright enough.  Unlike the rods in your eyes.  Which work well in low light levels.  Letting you see shades of gray in low light levels.  But saturate at high light levels.  Which is where the cones take over.

Light is electromagnetic radiation.  And the key to color is the wavelength.  What is a wavelength?  Think of a guitar.  If you pluck a thick string it vibrates at one frequency.  If you pluck a thin string it vibrates at a higher frequency.  The thick string will move back and forth at a greater distance (and a slower speed) as it vibrates than the thin string.  So the thick string has a longer wavelength than the thin string.  This is a crude explanation.  But the takeaway from this is this.  As frequency decreases wavelength increases.  As frequency increases wavelength decreases.

Different Wavelengths of Light have Unique Colors and are a Small Portion of the Electromagnetic Spectrum

Light is electromagnetic radiation.  Different wavelengths of light have unique colors and are a small portion of the electromagnetic spectrum.  If you ever conducted an experiment in grade school where you passed a white light through a prism (or if you saw the cover of Pink Floyd’s Dark Side of the Moon) you saw this.  White light enters the prism and a ‘rainbow’ of colors exits the prism.  Violet on the bottom.  And red at the top.  This is the visible light spectrum.  From violet (the smallest wavelength) to blue to green to yellow to orange to red (the largest wavelength).  Wavelengths smaller than violet are ultraviolet, X-rays and gamma rays.  Wavelengths larger than red are infrared, microwave, FM, AM and long radio waves.

In low light levels rods can make out things in shades of gray.  But cannot distinguish color.  As the light intensity increases the rods saturate and lose their ability to see.  While at the same time the cones begin to see.  There are three types of rods in the eye.  Those that see long wavelengths (around the color red).  Those that see medium wavelengths (around the color green).  And those that see short wavelengths (around the color blue).  These are the primary colors of light.  Red, green and blue.  If you add any combinations of these light wavelengths together you can get any color in the visible spectrum.  The cones will ‘see’ a color based on the combination of wavelengths they sense.  If the cones sense only red and green the eye will see yellow.  If the cones sense all wavelengths equally the eye will see white.

If you’ve ever bought a color inkjet cartridge, though, you may be saying this isn’t right.  Inkjet cartridge packaging has three dots of color on them.  None of them green.  There’re red, blue and yellow.  Not red, blue and green.  Green isn’t a primary color.  Yellow is.  And that is true.  When it comes to painting.  Or printing.  Or dyeing.  That uses subtractive coloring.  Where we use dyes, inks and pigments to absorb light wavelengths.  A blue paint, for example, will absorb wavelengths of all colors but blue.  So when you look at something dyed, printed or painted blue only the blue wavelength of the source light (such as the sun) reflects onto the cones in your eye.  The other wavelengths from the source light get absorbed in the dyes, inks and pigments.  And don’t reflect onto the cones in your eyes.

Our Brain blends Wavelengths of Color together into a Continuous Color Image

Artists mix paints together on a palette.  Each individual paint absorbs a set of wavelengths.  When mixed together they absorb different wavelengths.  Allowing the artist to create a large palette of colors.  The artist applies these colors to a canvas to produce a beautiful work of art.  But not all artists.  Georges Seurat didn’t mix colors together for his masterpiece.  A Sunday on La Grande Jatte.  The subject of Stephen Sondheim’s musical Sunday in the Park with George.  Where George explains the technique he used.  Pointilism.

Instead of mixing paints together to make colors Seurat applied these paints unmixed onto the canvas.  And let the eye mix them together.  The individual pigments absorbed all wavelengths but the desired color.  As these different wavelengths of different intensities fell onto the cones the brain blended these dots of color together.  In the musical George (Mandy Patinkin in the original Broadway cast available on DVD) shows someone what the painting looks like up close.  A bunch of dots of different colors.  And then moves backward with him.  As they do the dots blend together into a rich palette of colors.  Producing a beautiful painting.

In 4-color printing we use a combination of these techniques.  Where they reproduce a color photograph by blending the three primary colors (red, blue and yellow) and black.  The original photograph is broken down into its primary colors.  Before digital printing this was done with photography and color filters.  One for each primary color.  They then made screens for each color.  To vary the intensity of each color they broke solid colors into dots.  The amount of white paper showing between the dots of ink lightened the shade of the color.  The paper runs through a press that adds each of the primary colors onto the image.  Overlapping colors to produce different colors.  Subtracting wavelengths to produce a color image.  With the brain blending these colors together to reproduce the original color photograph.  (They added black to make a cleaner image than they could by mixing the inks together to make black.)

Video displays are more like pointilism.  Televisions in the days of picture tubes had three electron guns repeatedly scanning the phosphorus coating on the inside of the picture tube.  Each gun hit one of three different colors of phosphorus.  Red, blue and green.  These dots of phosphorus glowed at different intensities.  Each pixel on the screen has one dot of each phosphorus color.  The three colors blend together into one color pixel.  We use different technology today to produce the same wavelengths of red, blue and green.  That produce a color image.  That falls on the cones in our eyes.  With our brain blending these pixels of color together into a continuous image.

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FT115: “If you like the arts vote Republican because corporations need profits to make charitable donations.” -Old Pithy

Posted by PITHOCRATES - April 27th, 2012

Fundamental Truth

Starving and Suffering Artists

There’s a reason starving artists are calorically challenged.   There isn’t a large demand for them.  One of the greatest Post-Impressionist painters, Vincent van Gogh (1853- 1890), sold only one painting during his lifetime.  He suffered bouts of depression.  And in the end killed himself.  He was a man that truly suffered for his art.  He existed for his art.  And died a failure.  Of course, that was then.  Now if you stumble across a van Gogh in your parent’s attic you can probably retire early.  And live very well.

Stephen Sondheim’s Sunday in the park with George is a musical based on Georges Seurat’s A Sunday Afternoon on the Island of La Grande Jatte (1884–1886).  The musical is a multigenerational piece.  The story is part fact and part fiction.  In the first act Seurat loses his girlfriend, Dot, to Louis the baker because he can provide for her.  Unlike the starving artist.  Well, that.  And the fact that his art can’t share the artist with anyone else.  Though Dot leaves George with something of his.  A daughter.  The second act opens with George’s great grandson displaying his new sculpture and schmoozing with rich people who can fund his next work.  Because art costs money.  Like everything else in life. 

Georges Bizet was a French composer who died young.  And a failure.  At least he thought so.  During his lifetime he did not earn much of a living from his skills as a composer.  Instead he made a living by transcribing other people’s music.  Working long hours.  Through depression and ill health.  In his last years he completed an opera unlike any of the time.  He was very proud and pleased.  But, alas, the people and critics weren’t.  Shortly thereafter he died from a heart attack.  A young man of 37.  Sure that his works were as great failures as was his life.  But history lamented the early death of Bizet.  For his last opera, Carmen (1875), is one of the greatest and most beloved operas of all time.  And packs opera houses around the world whenever it’s performed.

Art Belongs to the Wealthy

Artists not only starve.  They suffer.  And it’s often their suffering that produces their greatest art.  As their art provides an outlet for their pain.  Which keeps them going.  At least for those who don’t quit life.  So when they can’t find rich patrons to fund their art they hunger and suffer more.  For it isn’t the poor who buy their work.  Not when they’re struggling to put food on their own tables.  Leaving them with little if any disposable income.  No.  Art belongs to the wealthy.  Some modern art has changed this.  Such as the music industry.  Where musicians can sell a work of art millions of time.  Something that just wasn’t available to van Gogh, Seurat or Bizet.  Though in the world of digital music some artists are experiencing what it was like during the times of van Gogh, Seurat and Bizet.  Where people copy their music from others instead of buying it.  Though their starving and suffering today is not quite what is was in the days of van Gogh, Seurat and Bizet. 

Also different today is that many artists don’t have to die before we recognize their talent.  Today you can make millions from your art.  While living to enjoy those millions.  Which for many is the goal of their art.  Today the artists live like the rich patrons did in the past.  Who didn’t create art.  But enjoyed it.  And paid for it.  Making art possible.  Today all it takes is to be popular.  You don’t even have to be good.  If you can ride a wave of popularity the people will shower you with money.  Which is a heck of a lot better than having to please a king or queen.  Or the rich upper classes.  So some artists are doing well.  These new artists.  While the old ones continue to suffer.  Well, not so much the old artists but the venues for their old art.  Where some things never change.  For this art is still the art of the wealthy.

Anyone can buy a ticket for the cheap seats at a symphony orchestra or an opera.  And they do.  Rich.  Middle Class.  Even the poor.  But these people aren’t patrons of art.  They enjoy some of it.  But not all of it.  They may buy a ticket for Beethoven’s 9th Symphony.  Or Bizet’s Carmen.  Or a showing of Post-Impressionism including van Gogh and Seurat.  So they’re less likely to buy season subscriptions.  And even less likely to make generous donations.  No.  These people enjoy a nice night out or two.  They don’t immerse themselves into the art.  Which is a problem.  Because art costs money.  Especially the ones with symphony orchestras.  Whose musicians tend to belong to unions these days.  Making a season of symphonic music very expensive.  As is a season of opera.  Which is even more expensive because they have very expensive singing talent.  Sets.  And all the people behind the scenes to make it all work.

Corporations and their Shareholders typically make the most Generous Donations to the Arts

Chances are if you went to a symphony or opera during the Great Recession you noticed some things.  For the recession caused great hardship for the arts.  Because when people lose their jobs they don’t buy tickets.  Or make donations.  When a corporation is losing money they make their donations less generous.  Or stop making them altogether.  Simply because the economy is so bad that their sales are down.  And they’re bleeding cash.  So just like people who lose their jobs cut out the nonessentials like vacations or going out to dinner, corporations have to make cuts, too.  Employee benefits.  Jobs.  And charitable donations.  Governments, too.  As unemployment rises more people fall into the social safety nets.  Unemployment benefits, food stamps, housing assistance, health care, etc.  Less economic activity brings in fewer taxes.  While the recession put more people into these programs.  They have to cut something.  And programs for the arts are high on their list.  Because human physical needs take precedence over spiritual needs.  For people can die if we don’t meet their most basic physical needs.

Art is a business.  Members in an orchestra don’t play for free.  Or cheaply.  If ticket sales and donations are down orchestra members may be unable to get the contracts they want.  And go on strike.  The orchestra, opera or ballet may shorten the season to cut costs.  And, of course, they will ask you for money at all times of the day and night.  Before performances.  In your email.  On the telephone.  Everywhere.  They’ll even approach you in a parking lot if you once made a donation but haven’t in the current year.  They will do this because people don’t universally love their art.  At least they don’t love it as much as they love their football, baseball, basketball or hockey.  Whose players have gone on strike.  But their seasons never lived or died from the affect of the economy on their rich patrons.  For sports is a business, too.  Only one with a far greater audience.  Which makes fundraising easy for them.  While it’s difficult in the arts.  For if just one corporate sponsor is struggling to survive bankruptcy and doesn’t contribute as they had in the past it could put the artistic business into bankruptcy.  Especially if they are already heavily in debt.  Which many are.

People in the arts eschew capitalism.  They say it is cold, harsh, cruel and callous.  That it’s all about profits and money.  Which they say is wrong.  And disgusting.  Not like their noble world of the arts.  Which is warm, caring, loving and nurturing.  For music has charms to sooth a savage breast.  As do the other arts as well.  The only problem is that so few people enjoy them.  Which means like in days of yore art still must rely on the generosity of rich people.  And corporations.  To make those big charitable donations.  Without which art cannot survive.  And what do rich people and profitable corporations need?  A healthy economy.  A free market economy.  That generates jobs for everyone.  Giving more people disposable income to try different things.  Like the arts.  And makes fat profits for corporations and their shareholders.  The people who typically make the most generous of donations to the arts.  The rich who don’t have to work.  And need something else to occupy their time.  Such as the arts.  So if you like the arts vote Republican.  Increase the pool of disposable income.  Where all charitable donations originate from.  So the rich patrons can pay for the Carmens of the world as well as the more obscure works no one has ever heard of.  Because these people love the arts.  And immerse themselves into them.  Giving life to more art than ticket sales alone could ever generate.  So thank these rich people.  These lovers of art.  And help them give us more art.  By letting them make money to give away.  And not demonize the thing that lets them do this.  Capitalism.

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