In fact this is a key way in which printed inks work google

canada goose black friday sale overview for wileycat canada goose black friday sale

canada goose coats on sale To understand this, imagine a thin, brightly coloured (orange for example) piece of transparent plastic (like a sweet wrapper). If we flattened it against a bright, white piece of paper the plastic colour canada goose uk shop would be very clearly visible. Imagine now, you put the same plastic over a matt black surface, the colour would be all but impossible to distinguish. This is because one substrate reflects a lot of light back through the plastic to your Canada Goose sale eye and the other canada goose coats does not. The buy canada goose jacket cheap printed ink film is essentially a cheap canada goose uk very thin (5 micron) canada goose black friday sale layer of coloured plastic. In fact this is a key way in which printed inks work google «CMYK color model» to see what I mean. canada goose coats on sale

buy canada goose jacket Note also that the reason the paper is white is because it is made up of bleached white wood and canada goose factory sale a significant amount of white inorganic filler pigments such as titanium dioxide. These inorganic pigments don absorb visible light at all. Generally ultraviolet light is higher energy, shorter wavelength light Canada Goose Online which we can see and which we are protected from by the ozone layer. Some UV gets through which is UVB and UVA. uk canada goose dyes being the chemicals we use to colour the ink we print things with). This process is photolysis and is usually the first stage in a whole series Canada Goose Coats On Sale of chemical reactions uk canada goose outlet which breaks down the highly coloured dyes on the CD covers and effectively canada goose uk black friday bleaches them. Because Canada Goose Parka the CD labels are screened by the glass window and the polystyrene case I would guess that a lot canada goose clearance sale of the UVB would not be getting through to cause this type of photo fading. buy canada goose jacket

Canada Goose Parka However, another process which is very common (and the primary cause of photofading) is called photo oxidation and as you might expect it is mostly the result of a reaction of the dyes with oxygen in the air. This reaction is sensitized (made worse by) UVA and visible light absorption by Canada Goose online the dye (or pigment) molecules in the printed ink. Now, the reason dyes are so coloured is because their chemical structure allows them to selectively absorb certain colours of visible canada goose clearance light, what remains un absorbed is the colour of the dye as you canada goose uk outlet see it. The example used elsewhere was the orange azo dye which absorbs mostly blue and green light to leave yellow and red (orange) light the «colour» of the dye Canada Goose Outlet as you see it. Canada Goose Parka

cheap Canada Goose Before a dye absorbs light it is said to be in the ground state. When it absorbs light, the electrons in the bonds holding the atoms together gain energy and move from one part of the molecule to another (HOMO to LUMO for the scientists). Once the dye has absorbed the light it is in an «excited state» (teehee!). How long this lasts is called the excited state lifetime and can be relatively long (nanoseconds), especially in the case of fluorescent and phosphorescent dyes. Fluorescent and phosphorescent dyes are the types of dyes used to give that Day glo effect, for example in high vis safety vests and signs. An important feature of this excited state is whether it is a triplet or singlet which is a term Canada Goose Jackets describing the spin of the excited electron in the canadian goose jacket molecule. Rose Bengal) a lot of the excited canada goose dyes are in the triplet state the majority of other dye types are mostly singlet though with a tiny proportion of triplet. cheap Canada Goose

canada goose store Now, molecular oxygen (O2) is very unusual in that in the ground state it exists as https://www.canadagooseoutlet4online.com a triplet and in the excited state as a singlet. As this is known as a spin forbidden process it almost never happens by the absorption of light alone. However, if a ground jacket state triplet oxygen molecule were to collide with a dye with an excited triplet state then energy can be transferred to oxygen and the transition from ground state triplet oxygen to excited state singlet oxygen can happen. canada goose store

canada goose Excited state singlet oxygen is a psycho and can be likened to the hulk in the Avengers movie; being very reactive towards anything close by. This can be a dye molecule or it can be water water can be transformed into peroxide which oxidises and breaks down the buy canada goose jacket nearby dyes. Note also that singlet oxygen canada goose coats on sale in the gas phase has a cheap Canada Goose much longer lifetime (an hour or more) and so canada goose store even if the process of creating it is very slow or inefficient it can still hang around long enough to react with something. canada goose

Canada Goose Jackets TL:DR The dyes themselves aggravate oxidative bleaching when they absorb light. Canada Goose Jackets

buy canada goose jacket cheap Oh yes, forgot to make the point that the red may seem to have faded more than the others because the blue dye used (or Cyan, from CMYK printing) is almost certainly copper phthalocyanine based which has phenomenal light fastness buy canada goose jacket cheap.