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Comment by layer8 | Hacker News Reader

Before Lightroom it might have looked closer to this: https://images-assets.nasa.gov/image/art002e000193/art002e00...

From the EXIF we can infer that every setting was left at the default. No exposure comp, no contrast, no HSL, no lens correction and a linear tone curve. Just the default Adobe Color profile at 5400K.

The photograph appears to show nightime on Earth with just a sliver of daytime. Beyond cities in Iberia and along the coast of Africa, most of what we can see would be reflected light from the Moon? We are just past full moon on April 1.

1/4 exposure time so 250 ms of light. the light is coming from all the light sources in the universe, plus the moon, plus the sun's rays refracting through the atmosphere which happens even at night.

The natural blue light is coming from the oxygen in the atmosphere but it's so overwhelming in that spot that it turns the light pure white. The red/orangish is coming from particulates and the green/red from aurora. My favorite part I think is the very bottom where you can see the blue light taper off and not overwhelm the camera sensor and you can see the aurora with it. I love this photo so much.

Probably my favorite photo ever now.

> the light is coming from all the light sources in the universe, plus the moon

And all the others are negligible by many orders of magnitude compared to the moon. So it's really just the moon as far as this photo is concerned (except for the small sliver that's still illuminated by sunlight, including refracted sunlight).

> the light is coming from all the light sources in the universe,

That's highly incorrect. I have many lightsources that aren't contributing to any photons in that picture. For example my refrigerator light.

I turn off my refrigerator light after I close the door by reaching in and pushing the button. Don’t you?

so the atmosphere acts as giant lamp lit from behind by Moon? never thought of it that way

> the light is coming from all the light sources in the universe, plus the moon

This is true for every photo ever taken

That's what the caption the article above says

> Beyond cities in Iberia and along the coast of Africa, most of what we can see would be reflected light from the Moon?

Yes, exactly.

Made me look for the first pictures of earth

https://en.wikipedia.org/wiki/Timeline_of_first_images_of_Ea...

- first video listed https://en.wikipedia.org/wiki/File:1946-11-21_White_Sands_NM...

quite amazing

Maybe it’s because I (like many) have experienced taking pictures at night and seeing the grainy result that _this_ image struck me as incredibly realistic.

Almost like I ran the grainy-to-real conversion in my mind and I felt like I was imagining seeing this in person. Beautiful image!

It's beautiful as these all are, that one is probably my favorite. And as somebody else said it kind of feels more real seeing the grain like that. It's just beautiful. A side we never see quite like this.

Might I ask, what was your path to finding this image?

https://www.nasa.gov/gallery/journey-to-the-moon/

Thanks so much. Sending this link to my nerdy nephews immediately.

But that one (art002e000193~large.jpg) is only 287kB. The Lightroom-processed one is 6.2MB. I would expect original to be heavier.

The Lightroom one was processed from raw. Also, by brightening it a lot, the noisy high-ISO grain becomes more apparent. Noise is famously incompressible, so it leads to a much larger file size.

Brightening the image may make the iso noise easier to see, but it doesn't create it.

Noise that's easier to see will not be compressed away by the JPEG compression. JPEG is basically just DCT + thresholding. Any higher amplitude noise is going to stay and increase the final file size.

Also, pulling more data from your 14 bit or 16 bit raws results in more noise in the end compared to the straight-out-of-camera 8 bit JPEGs.

But lossy-codecs job is to utilize psychovisual tricks to discard as much high-frequency information as possible, whilst remaining similar visual effects. If you increase the brightness in RAW and then re-encode the JPEG - more noise is being pulled up in the visual spectrum, therefor less of that information (filesize) is discarded.

For example, if you render Gaussian noise in photopea and export as JPEG 100% quality, it has 9.2MB. If you reduce the exposure by -2 it goes down to 7.8MB. That's partially because more parts of the noise are effectively black pixels, but also I believe because of the earlier mentioned effect.

It's not lossless

The resolutions are different, 1920x1280 vs. 5568x3712.

Also possibly different JPEG quality settings.

Could be the thumbnail / preview image generated alongside the raw

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