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Comment by makmanalp | Hacker News Reader

> the fact that data can be copied perfectly, as many times as you want

Tangentially, this makes me wonder: While microfilm can't be copied perfectly, isn't it true that the source quality (e.g. the crispness of the print) is vastly lower than the resolution of the medium itself? Which seems like it would imply that the "lossy" transformation might in some sense still lossless, at least for a while - like converting a high bitrate mp3 recording of a radio broadcast into a lower bitrate one. Or perhaps the kinds of loss are different. I'm sure I'm confusing a lot of ideas and butchering some terms here.

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You're right! Copying to a higher-definition medium should in theory allow for effectively lossless copies.

There is a potential catch, in that analog copies will tend to introduce some amount of physical errors no matter how much the hypothetical increase in definition should allow for perfection. Subsequent copies, no matter how high their quality, will both tend to amplify these errors and introduce new ones. You get a similar result if you repeatedly re-endcode data even in high-fidelity lossy ways - each encode introduces artifacts and amplifies previous artifacts.

It's an intriguing idea! Thank you for bringing it forth for discussion.

Microfilm is pretty high resolution. How much does a 10K scanner go for these days?

I think you're trying to say something, but I'm getting lost in the details. Can you elaborate more on what you mean by source quality / crispness of the print / resolution of the medium itself? What items are you comparing? Please be specific.

With arbitrary numbers: if the original paper was printed at 100dpi, and the film captured 1000dpi, then the losses from copying that film might not make a real difference in fidelity.

In the analog world, you have to think about signal-to-noise ratios instead of DPI. Any given copying technique will add some small but nonzero amount of randomness to the output, which destroys some information.

The way digital copying gets around this problem is by having predefined signal levels that are farther apart than the vast majority of copying error, and writing a new master every time instead of the analog copy.

The first copy is unlikely to, since a random error (i.e. an unintentionally developed silver grain) will only introduce a distortion 1/10th the size of the original smallest detail. But what about after 10,000 copies? Scattering random 1/10th sized blobs all over the original details is still going to do something to the experience.

Sure, so long as you assume the transfer is 100% perfect with no errors or artifacts and can make subsequent copies similarly. In practice, few physical processes can offer that level of assurance, and digital copies can.

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