How big can I print my image?

by LorenDB • 12 months ago

61 11 12 months ago

tl;dr:

    Viewing distance PPI
    1 meter          170 pixels/inch

which is to say that a 12mp image is going to max out at 18x24"

alwa• 12 months ago

…supposing the pixels are the limiting factor, and that you’re interested in viewing an 18x24” image from 3 feet away.

If the optics that captured the image are such that its sharpest feature spans multiple pixels, TFA provides some handy rules of thumb to adjust your print size down accordingly.

dsign• 12 months ago

Half-in-jest, I think we should put some pressure on the International Bureau of Weights and Measures to standardize dots per meter (DPM), and then have the EU follow through with a new law or two to accelerate adoption.

ggm• 12 months ago

Yes, the meter/inch thing is jarring.

Angular measure only has degrees. We should be fine with angles subjected to a point, unless somebody decided fractions beat decimals.

throw0101c• 12 months ago

Angular measure only has degrees.

The SI unit for angular measure is radians:

* https://en.wikipedia.org/wiki/Radian

Also:

* https://en.wikipedia.org/wiki/Angle#Units

Eisenstein• 12 months ago

"Zoom into this image so that the width of each vertical line is 1 mm or the whole image is 3.2 inches wide."

Is it possible to pick one system? Also, "3.2 inches" is difficult to measure. Rulers that measure in less than an inch use fractions, not decimals. It usually goes by 1/8ths, then 1/4 and 1/2, but some rulers have 1/16ths. 3/16" is .187 inches which is pretty close I guess.

funac• 12 months ago

"Zoom into this image so that the width of each vertical line is 1 mm or the whole image is 3.2 inches wide." > Is it possible to pick one system? Also, "3.2 inches" is difficult to measure. Rulers that measure in less than an inch use fractions, not decimals. It usually goes by 1/8ths, then 1/4 and 1/2, but some rulers have 1/16ths. 3/16" is .187 inches which is pretty close I guess.

decimal inch rulers (& tape measures) are available; i have several. imo they're much more useful than fractional rulers in the context of machining, where the natural base unit, if you're not in metric, is 0.001” ('one thou')

perching_aix• 12 months ago

Unfortunately printers print in dots though, not pixels. There are printers with variable dot sizes, supposedly a thing with professional print, I wouldn't know - but nominally a dot is gonna be one of the four ink colors (cyan, magenta, yellow, black) and then it's either present or not present. I'm sure someone who didn't sleep only just one hour overnight can calculate you how many dots you need to cover the same gamut as a typical 24 bit SDR RGB pixel will.

jjcob• 12 months ago

24?

pointlessone• 12 months ago

8 bits per channel. 8 * 3 = 24

MrSkelter• 12 months ago

Good luck printing anything at 870dpi.

This whole article is a bit confused. Image quality isn’t about the ability to discern detail. Many people cannot see the detail in their 4k TVs or a photo, it’s about not seeing visible pixelation.

Those aren’t the same thing. Visible pixelation is connected to contrast and color depth. That’s why a perfectly smooth gradient appears as bands of color in poorly encoded images and video. There’s no detail in gradients at all. The pixelation is due to a lack of color information.

On top of that printers use different numbers of colors (from 3 to 11 or more) and different ways of sizing and layering dots (if you aren’t using continuous tone printers which are very rare nowadays).

Then you have to add in the ability to up res images plausibly using modern algorithms. Whereas before we were always stretching the data we had, now by adding false detail using ML we can scale a significant amount without a visible reduction in quality. That can be very effective at removing pixelation while preserving the original image content.

So in reality there aren’t hard and fast rules. It’s totally image and output dependent.

How big can I print my image?

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