Color Printing Reaches Its Ultimate Resolution

ananyo writes "The highest possible resolution images — about 100,000 dots per inch — have been achieved, and in full-colour, with a printing method that uses tiny pillars a few tens of nanometres tall. The method could be used to print tiny watermarks or secret messages for security purposes, and to make high-density data-storage discs. Each pixel in these ultra-resolution images is made up of four nanoscale posts capped with silver and gold nanodisks. By varying the diameters of the structures (which are tens of nanometres) and the spaces between them, it's possible to control what colour of light they reflect. As a proof of principle, researchers printed a 50×50-micrometre version of the 'Lena' test image, a richly coloured portrait of a woman that is commonly used as a printing standard (abstract). Even under the best microscope, optical images have an ultimate resolution limit, and this method hits it."

Re: optical images have an ultimate resolution lim

[schroedingers_hat]

Those things would not be Color printing. In fact, you could view this process as monochrome too, except when the comparitively long wavelength visible light hits it, it acts in a similar way to a pigmint (well, diffraction isn't exactly the same, but similar enough).

Re:In other news...

[Tubal-Cain]

I can think of one way their claim can be entirely true, and not just another shortsighted statement like Duell's:
If they make it any smaller, they won't be dealing with visible light anymore.

Re:In other news...

[uradu]

http://en.wikipedia.org/wiki/Charles_Holland_Duell [wikipedia.org]

Famous statement attributed in various forms to various people throughout history. Duell's actual statement (provided that was attributed correctly) was the exact opposite of this.

Re: optical images have an ultimate resolution lim

[hamjudo]

This just hits the resolution limit for color printing that includes red. It is possible to make color images with just greens, blues and violets at a higher resolution, it just wouldn't count as full color. Researchers could go to even higher resolutions, if they just use blues and violets, but they wouldn't be able to render a very convincing human flesh tone. Competition will start shortly, for the smallest smurf vision display.

Re: optical images have an ultimate resolution lim

[arielCo]

You can't see much smaller than the wavelength used, and they're talking about visible light. It's in TFS:

Even under the best microscope, optical images have an ultimate resolution limit [wikipedia.org], and this method hits it.

And the linked Wikipedia article quoth:

With green light around 500nm the Abbe limit is 250nm.

That's a bit more than 100,000 dpi. Visible light goes down to 380 nm (~133,000 dpi), so you'll never see anything smaller by optical means.

Re:Added home utility

[dgatwood]

If you don't care about size, I recommend networked color laser printers. No more clogged printheads, no more quirky drivers that break every other release (they speak PostScript), usually at least 5 PPM in color even for the small ones, and the bigger ones will do as much as 25 PPM in full color. Of course, they don't cost $50, but you also don't pay $50 in ink every time you need to refill the thing. (Okay, so you pay a couple hundred bucks in toner, but for home use, you refill the thing every five years instead of every month or two, so it works out to being a lot cheaper.) And instead of replacing the whole thing every couple of years when the print head finally gives up the ghost, you'll still be using the same color laser printer in a couple of decades.

Re:In other news...

[phantomfive]

And you are correct. If they printed it any smaller, the colors would start blurring together because of the wavelength.

Here's a picture if you want to see it [nature.com]. Although it is small, fidelity to the original image is clearly low. The technique could use some improving. Still cool.

Re: optical images have an ultimate resolution lim

[Anonymous Coward]

With near field optics [wikipedia.org], you could see things much smaller than the wavelength. Even with practical limitations, current technology can sometimes see with resolution and order of magnitude or two below the wavelength. The only catch is it requires optical elements or structure to be placed at distances on the order of a wavelength or less from what is being observed. So it is limited to some very specific uses.