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Comment by douglaswlance | Hacker News Reader

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douglaswlance

Every screen and printer will display/print colors differently. This is not a good idea.

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Every HN comment thread is full of armchair critics. Maybe the designer actually thought of this!

If the colors are quantized into a constellation, even significant error could be corrected.

Except if said colors fade over time or change their hue due to UV exposure like most pigments used for printing.

QR codes printed on thermal paper also fade over the course of a year and would be unreadable. There are always uncorrectable adverse conditions.

Sure. And if you light the paper on fire even 24pt Helvetica becomes unreadable.

But I’m sure you too feel that the failure modes of this colored barcode form a proper subset of the failure modes of its monochromatic counterpart.

Well, if your machine-readable color key fades as well, maybe it's not so much of a showstopper if the colors fade.

The primary problem I see is that so many industrial cameras today are black and white. B&W cameras can send at a higher framerate and you don't need to convert to greyscale as your first step in your algorithm, so it saves time to use b&w cameras.

Well, I hope the designer accounted for multiple colors failing to displayer properly. The pink and red are impossible to discern for me. My bank uses colored QR style codes and they're impossible to use with (very common) blue light filters active in the evening hours.

Every HN submission is treated as if it's a breakthrough discovery to herald in a new era of human society. Constructive criticism (like the parent comment of your comment) is helpful, considering that the author of JAB Code makes no mention of this obvious issue (that I could find).

You should read the specification. It more than mentions this. It is discussed in sections 3.3.8, 5.5, 6.5, and annex F.

The full color palette is embedded in every code, so the reader need only compare a cell's color to the colors in the palette region.

Printed colors fade at different rates and shift color in different ways.

The palette is embedded in the barcode which would presumably fade the same way the rest of the barcode does.

This would fail if the decoding algorithm was trying to match exact RGB or YUV values. But in reality, all it has to do is disambiguate 8 (in the case of the example) colors.

I went to the sample page and you can generate one with up to 256 colors.

Yes but you don't need exact colors. Just a limited set of colors that can be matched up, especially after correcting for white balance.

Depends on the chromatic differential it’s using, along with its error correction.

Why wouldn't/couldn't this thing just disambiguate colorspace the same way it does rotation/position with predefined locator patterns?

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