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Comment by jacobolus | Hacker News Reader

Marketing copy exaggerates a bit, film at 11.

You are right if they wanted to really push the limits of human perception they could develop custom printers or buy some machines used for physics experiments or integrated circuit fabrication or whatever and try to print at 1200+ pixels/inch.

Realistically, what they are doing is making full resolution prints on commercially available large-format photograph printers, with their effort going into tweaking the shaded relief algorithms and applying photoshop filters to boost local contrast.

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I think you're being unjustifiably uncharitable by accusing them of intentional fraud. I think they're just fooling themselves because they're carried away by their enthusiasm for what they've created, which is really pretty cool.

You don't need custom printers to print at 1200+ pixels per "inch". Most off-the-shelf inkjet printers and some laser printers can do it, though at high resolutions there's a serious tradeoff between precise color and precise position. https://news.ycombinator.com/item?id=27965938 points out that standard imagesetters are 2540 "dpi" (and they have been since the 01980s). Photographic processes routinely produce images with a resolution below 10μm (2540 "dpi") and, when desired, below 2μm (12700 "dpi"). I don't mean with some kind of super niche lab equipment; I mean Kodak point-and-shoot cameras with mass-market Kodachrome film. Metal machining routinely hits precisions of 25 μm (1000 "dpi") and has for a century and a half, sometimes using machines made out of junk using nothing but hand tools; when it matters, it gets down to 1 μm (25400 "dpi"), which is roughly the measuring repeatability of any old handheld micrometer. You can buy such a micrometer on eBay for US$30 https://www.ebay.com/itm/363415676100?hash=item549d4324c4:g:... though a quality one probably costs US$60 or more, even used.

What made Harrison's achievements with the diffraction-grating ruling engines 70 years ago remarkable was not that he could position the ruling engine in increments of 25 nanometers or better (a million dpi); that, and even 2-nanometer increments, had been achieved for small gratings about a century earlier. His achievement was maintaining a total error under 5 nanometers across a distance of over 200 mm during the weeks necessary to rule a full diffraction grating. (I think the Richardson Grating Lab still uses the Michelson ruling engine he overhauled in the 01940s, though with further improvements.)

Fraud? Huh? When they say that these maps are the “most detailed” in their marketing materials they clearly mean that they are using a digital elevation model with higher resolution than the ones used to create other similar images available for sale elsewhere. They obviously use relatively standard digital photo printing processes, and are not implying otherwise. If you have your own source file, you can get it printed/mounted using similar technology from your favorite commercial print shop.

One can certainly produce a higher resolution image using various technologies (as you say, a photographic negative potentially has very high resolution). But so what? I really have no idea why you are talking about micrometers, diffraction gratings, and so on.

I came here to tell you, kragen, that I am enjoying your zeros before 4-digit dates, your derision of old units, etc. Oh, that and your informative comments, of course.

> Realistically, what they are doing is making full resolution prints on commercially available large-format photograph printers, with their effort going into tweaking the shaded relief algorithms and applying photoshop filters to boost local contrast.

Yes, exactly this.

> Marketing copy exaggerates a bit, film at 11.

And yes, also this, ha. We sell wall art, so the article is intended to convey that for something you look at on a wall, we're running up against the limits of what a human can see, with normal vision, at any reasonable viewing distance. It is absolutely true that someone with good vision, the right light, and a magnifying glass could probably see some dots, but that's not typically how wall art is viewed, which is what we design for.

You should probably fix that, because lying about your product in order to get people to buy it is fraud. Even if you don't care about the ethical issues, it could have negative repercussions for you in the future. It looks like it's good enough that people would buy it even if you didn't lie about it, so I think you should capitalize on that. (Maybe you disagree? People who notice the lie will think you don't think it's good enough to sell without lying about it, and they'll wonder what else you're lying about.)

Also 300 dpi is coarse enough that, despite my aging vision, I wouldn't need a magnifying glass or particularly good light to see the jaggies from 300 mm, and I think that is a reasonable viewing distance for wall art. 300 dpi is definitely not a "gold standard" for coffee-table books or wall art. Someone with good vision, the right light, and a magnifying glass can see features at 2400 dpi, 64 times the number of pixels you're using. Why do you think Linotype made 2450 dpi the Linotronic resolution 35 years ago? Perhaps you think they didn't have any experience with printing?

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