Why do certain types of paper turn yellow faster than others?
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Paper is made from wood, which is made up mainly of white cellulose. Wood also has a lot of a dark substance in it called lignin, which ends up in the paper, too, along with the cellulose. The exposure of lignin to air and sunlight is what turns paper yellow.\n\nLignin makes wood stiff and trees stand upright. You could say it acts as a glue to bind the cellulose fibers together. It is a polymer, a substance that is formed by the joining of simpler molecules into giant molecules that act differently than the smaller molecules did. Dr. Hou-Min Chang, a professor of wood and paper science at N.C. State University in Raleigh, N.C., compares lignin to the concrete used in buildings, with cellulose as the steel frame. Without lignin, Chang says, a tree could only grow to be about 6 feet tall. Lignin also helps protect the wood from pests and other damage.\n\nNewsprint, which must be produced as economically as possible, has more lignin in it than finer papers. At the mill, the wood that will be turned into newsprint is ground up, lignin and all.\n\nPaper manufacturers utilize the benefits of lignin in some types of paper, though. Brown kraft paper, the dark brown paper used in grocery store bags, and cardboard are stiff and sturdy because they have more lignin in them, and because those kinds of paper aren't treated with bleaching chemicals. It doesn't matter how dark they are because the printing on them is limited.\n\nTo make a fine white paper, the mill puts the wood through a chemical solvent process, which separates and discards the lignin. Pure cellulose is white, and the paper made from it will be white and will resist yellowing.\n\nLignin eventually turns paper yellow because of oxidation. That is, the lignin molecules, when exposed to oxygen in the air, begin to change and become less stable. The lignin will absorb more light, giving off a darker color. Chang says that if newsprint were kept completely out of sunlight and air, it would remain white. After only a few hours of sunlight and oxygen, however, it will start to change color.
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because after 7 fold the thickness of the paper is greater than its length.
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The temperature of the sum's surface gives it's characteristic color. If an object with a small hole in it were heated to the same temperature the light comming out of the hole would have the same temperature. i.e., black body radation.\n\nAlso because our eyes the characteristic light as yellow. Namely, the three color sensors in our eyes senses the Yellow more brightly than the red and blue. So, we see yellow.
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So they are easily seen.  Most Post-it pads are stuck on white papers to furnish additional information.  If they were also white, they would not stand out and see easily seen.  Yellow is any color of light that stimulates both the red and green cone cells of the retina and therefore it "catches you eyes". That is why you see so much yellow in the transportation industry.  Such as Yellow lines on the sides of roads and yellow school buses.\n \nThe majority of Post-it are yellow, but now come in many "designer" colors.
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I have a theory.  Paper is semi transparent to start with.  That is why you can 'trace'.  Now, paper is made of small fibers.  The fibres are aligned randomly.  Each fibre is reflecting light in a different direction and you see white if no dye has been added.  Well, put oil on top of the paper and the light will not reflect back at you as much.  Without this interference (reflection) you can see through the paper more easily.\n\nAs an analogy .. if you look west across a lake an hour before sunset, you can't see the other side as well because of the glare.  The other side is other wise easy to see.  Cut down the glare and you can see the other side more easily.
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Because when it's hard to tear the paper (newspaper, computer paper, whatever) you're going against the grain of the paper. In that: paper is formed smuching lots of little peices of pulp together, and usually all the pulp is facing one way, if you tear it in a way that goes with it, then it's easy to tear, if you tear the other way you get the zigzag thing that happens because you are tearing it across the line of pulp. Understand? Kind of?
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Talk about how paper is made.
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You can get putty like ones from art shops that remove dark HB and pretty much destroy anything apart from the pressure on the paper. they need to be cleaned a lot but can be molded to an easy shape and are dabbed rather than rubbed which means less white flakes and little paper ripping.
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To answer your question, let me tell you the Basics.\n\nPrinter uses Black cartridge and Color cartridge\nColor cartridge normally contains 3 colors namely Cyan, Magenta & Yellow\n(Few models of printer has separate Cyan Cartridge, Magenta Cartridge and yellow Cartridge)\nThese 3 Colors are sprayed with different concentration of colors on the media (paper) like dots (very very tiny dots) by the printer at precise distance.  And these colors at different concentration gives you the illusion of different colors. \nCheck this link which gives you how this works exactly\nhttp://en.wikipedia.org/wiki/Half_Toning\n\nHope the info was helpful!!!
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there are many diferences:\n1)acid turns litmus paper blue to red while base turns litmus from red to blue\n2)acids produce H+ ions in aqueous solutions \nbases produce OH- ions in aqueous solutions \n3)acids are proton donors \nbases are proton acceptors
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the color of the food is recolored by the bile juice . bile juice absorbs the color pigments in turn produces yellow pigment that colors the material . \n10 points pls .
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I heard it makes it yellow
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It will be used in reference to a prism.\n\norange light has more wavelength thanx yellow.
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The same thing that gives a banana it's yellow color?
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maybe yellow jaundice hence yellow
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No heavy, toxic metals in printing ink that I know of.  The black color comes from carbon black (soot).  Colored inks use other organic pigments.\n\nNewspapers used to use lead (Pb)-, cadmium (Cd)-, and chromium (Cd)- based inks, but that practice was discontinued years ago.\n\nCheck it out here:\nhttp://answers.google.com/answers/threadview?id=97405
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Take a magnifying glass and look at a printed picture. You will see a lot of dots. That is how shades of gray are made on a printing press. To see this look at a black and white photo in a newspaper.\nAnd colors are made using only 4 colors of ink: Cyan, Magenta, Yellow and Black (CMYK). Look closely at a magazine cover for that example. Or more easily seen on color comics in the Sunday paper (heavier screening).\nTo print an image, the picture has to be transfered to a inked metal plate that transfers the image to the paper. There is no way to smear the ink in varying thicknesses. It can only make differences in darkness by using the screening technique, which means making the image into a series of dots (A screen). The distance between the dots determines the apparent darkness of the image. (Close together=darker. Far apart=lighter.) This used to be accomplished in the dark room with a camera and a sheet of film with the appropriate sized dots on it. Now it is done by outputting the image to film from computer which performs this function automatically. \nThe "screen size" is dots per inch (dpi) or lines per inch (lpi). Newpapers have faster, lower quality requirements for their product and typically use screens of around 80-100 dpi, while commercial, high end printshops doing 4 color work may use 1200 dpi, or higher screening.