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Printer ink is often of different colours and black printer
ink is usually unable to produce saturated tones. This
means different inks have to be produced, which is
unnecessarily complex.
Greyscale can be imitated by halftone. Presumably,
halftone using dots between one and about twelve
microns, separated by the same order of distance would
look like greyscale to the naked eye. But what happens if
the dots and the separation are both between three
hundred and eight hundred nanometres? I'm not good at
this, so help me out please. Does it not mean that a
surface covered in such a halftone pattern would look
coloured rather than greyscale?
Having said this, paper has a rough surface. It's a mat of
lumpy vegetable gunk on the whole, unless it's made of
beetles, polythene or something. I imagine this would
mess the spacing up somewhat and make the colour non-
Lambertian. So, it's not enough just to fling precise globs
of goo at a surface like Francis Bacon. That surface has to
be even.
Well, to make a virtue out of a necessity, before you start
doing that, coat the paper with a translucent white layer,
very evenly, then throw the particles of ink with a precise
force to embed them at different distances from the
surface of the coating. This would afford different levels
of saturation too, though the scattering introduced by the
translucency would presumably also mess up the diffraction
thing.
So, how to do the spacing and size? Use a printer head
which consists of an adjustable grid of squares a total of
twelve microns on a side with each square adjustable to
within the limits of the visual spectrum along with the
gaps, avoid viscosity problems by making the ink gaseous
and hot, with a subliming point above the temperature at
which paper catches fire (which is not four hundred and
fifty one degrees F of course), and methinks one has a
printer which can generate its own colour ink from black
toner. No idea what kind of gas or coating to use though.
Colour Holography
http://school.maths...sis03.htm#Heading32
One method for creating true-colour holograms. [Wrongfellow, Jul 19 2011]
Colour Holography 2
http://www.wired.co...plasmonic-holograph
Another way to do it - more high-tech, but perhaps less relevant to this idea. [Wrongfellow, Jul 19 2011]
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I'm not sure about this - you talk about placing ink particles on the paper close enough to each other to create diffraction effects, and thus different colours, however the point about this method of creating colour is that ink isn't needed - all the colour is created by the structure of the surface. So, the iridescence on a butterfly's wing might be created by material all of the same colour. Another way to do this would be to not use ink at all, but instead use a laser to etch diffraction patterns in the surface of the paper. |
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Ooh, i like that! In which case ink is entirely unnecessary and it's less fiddly. |
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//...use a laser to etch diffraction patterns...// |
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If you're doing this, why stop at colours? You can use it to print a hologram. |
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That's horses for courses really though, because is it not a case of either realistic colour or a hologram? |
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Not if you don't restrict it to a monochromatic light source. (2 links for the price of 1!) |
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I like this. It should work, using a shiny paper and
an opaque ink - you'd basically create a diffraction
mirror. |
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You'd have to be very accurate, though (I'm
guessing you'd need accuracy down to a tenth of a
wavelength, say 50nm), and the colour would
depend on the angle you viewed it from. |
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An alternative approach would be to coat a
reflective paper with a continuous layer of
transparent, lacquer-like ink of precisely-
controlled thickness. I inadvertently did this (on
a silicon wafer substrate), and the intensity of the
colours is absolutely astonishing. |
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Unfortunately the difference between my MBE
machine and my printer is that only one of them has
a USB port to connect it to my computer. |
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I am left with the impression of a rapid prototyper which can produce medals, though i presume you're talking about some semiconductor producing thingy. There would presumably be iridescence. Maybe it would also be able to conterfeit banknotes? |
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