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Unfortunately I expected a more substantial quantitative analysis rather than this nonsense: > Noise, by nature, is digital so it is all square-shaped, like a

by shrx 4y ago

Unfortunately I expected a more substantial quantitative analysis rather than this nonsense: > Noise, by nature, is digital so it is all square-shaped, like a pixel, and it’s uniform in nature because pixels are just a grid of little, tiny squares. So when you look very closely you can easily tell that noise and grain are two very different things with grain achieving actual randomness of size and positioning while noise is just a table of black, white, and grey squares. edit: And calling film grain "organic" is a bit of a stretch, it's silver halide crystals.

underwater 4y ago
The point seems valid: that digital noise will be per-pixel (as will noise from digital sensors). Whereas a scan of film grain is capturing literal grains which will not align perfectly with scanned pixels. The comparison image shows this.
- shrx 4y ago
  You can generate noise with whichever shape, size and frequency distribution you need. It's entirely possible to emulate film grain computationally. one example: A. Newsom: Realistic Film Grain Rendering https://pdfs.semanticscholar.org/b791/566b0a38cc0269b1b7f9adbe5ba569aa4eb5.pdf https://pdfs.semanticscholar.org/b791/566b0a38cc0269b1b7f9ad...
  - underwater 4y ago
    That's why I said digital noise. If you're using randomness to generate something that emulates film grain then by definition it's not noise, it's a procedurally generated texture. The point was that many editing tools offer noise generation that works at a pixel level. The author was explaining why those are unsuitable for the task. That doesn't make it nonsense.
    - ginsider_oaks 4y ago
      Are noise and procedurally generated textures mutually exclusive? The Wikipedia article for gradient noise[1] says: > Gradient noise is a type of noise commonly used as a > procedural texture primitive in computer graphics. [1]: https://en.wikipedia.org/wiki/Gradient_noise https://en.wikipedia.org/wiki/Gradient_noise
- dorkwood 4y ago
  That's only if you're generating noise based on pixel coordinates. It's possible to generate digital noise of all different sizes and shapes.
- jameshart 4y ago
  Pixels are not squares. Pixels are sample points, arranged on a square grid. One of the things you can do with those sample points is fill in the whole square around them in the color of that sample point. But that is not 'what pixels are'.
  - nomel 4y ago
    In the context of what they said, pixels are the smallest unit of a display, all you will ever see with your eyes if looking at a display, and they are almost always square. Having them represented as a circle or diamond wont change the point they were making.
    - jameshart 4y ago
      They’re not actually square, though. They’re (on almost any display technology) a mosaic of red green and blue patches arranged inside a square. On a ‘retina’ class display these square areas are explicitly smaller than the resolution distinguishable by your eyes. Any sharp edges or corners you think you can discern are your mind reconstructing an edge from a series of neural samples on your retina that are the sum of the output of various sub pixel blobs of red green and blue light that focus on that particular cluster of cone cells.
      - nomel 4y ago
        > arranged inside a square. That is what we call a pixel: the smallest representation of a point of full color. But, none of this matters for the point they were making.
- yarg 4y ago
  It doesn't have to be. A voronoi based vector codec could probably be close enough that people would struggle to tell the difference from film.
dTal 4y ago
Presumably "organic" is here used in its figurative meaning of "[chaotic] result of a natural process", rather than "carbon-based compound".
nkrisc 4y ago
> edit: And calling film grain "organic" is a bit of a stretch, it's silver halide crystals. I thought it was super obvious they didn’t mean organic in the chemical sense.
cratermoon 4y ago
And yet, film developers like phenidone, hydroquinone, and metol are all organic compounds. And once developed, there are no halogens left, it's metallic silver.

by shrx 4y ago

underwater 4y ago

The point seems valid: that digital noise will be per-pixel (as will noise from digital sensors). Whereas a scan of film grain is capturing literal grains which will not align perfectly with scanned pixels. The comparison image shows this.

shrx 4y ago
You can generate noise with whichever shape, size and frequency distribution you need. It's entirely possible to emulate film grain computationally. one example: A. Newsom: Realistic Film Grain Rendering https://pdfs.semanticscholar.org/b791/566b0a38cc0269b1b7f9adbe5ba569aa4eb5.pdf https://pdfs.semanticscholar.org/b791/566b0a38cc0269b1b7f9ad...
- underwater 4y ago
  That's why I said digital noise. If you're using randomness to generate something that emulates film grain then by definition it's not noise, it's a procedurally generated texture. The point was that many editing tools offer noise generation that works at a pixel level. The author was explaining why those are unsuitable for the task. That doesn't make it nonsense.
  - ginsider_oaks 4y ago
    Are noise and procedurally generated textures mutually exclusive? The Wikipedia article for gradient noise[1] says: > Gradient noise is a type of noise commonly used as a > procedural texture primitive in computer graphics. [1]: https://en.wikipedia.org/wiki/Gradient_noise https://en.wikipedia.org/wiki/Gradient_noise
dorkwood 4y ago
That's only if you're generating noise based on pixel coordinates. It's possible to generate digital noise of all different sizes and shapes.
jameshart 4y ago
Pixels are not squares. Pixels are sample points, arranged on a square grid. One of the things you can do with those sample points is fill in the whole square around them in the color of that sample point. But that is not 'what pixels are'.
- nomel 4y ago
  In the context of what they said, pixels are the smallest unit of a display, all you will ever see with your eyes if looking at a display, and they are almost always square. Having them represented as a circle or diamond wont change the point they were making.
  - jameshart 4y ago
    They’re not actually square, though. They’re (on almost any display technology) a mosaic of red green and blue patches arranged inside a square. On a ‘retina’ class display these square areas are explicitly smaller than the resolution distinguishable by your eyes. Any sharp edges or corners you think you can discern are your mind reconstructing an edge from a series of neural samples on your retina that are the sum of the output of various sub pixel blobs of red green and blue light that focus on that particular cluster of cone cells.
    - nomel 4y ago
      > arranged inside a square. That is what we call a pixel: the smallest representation of a point of full color. But, none of this matters for the point they were making.
yarg 4y ago
It doesn't have to be. A voronoi based vector codec could probably be close enough that people would struggle to tell the difference from film.

dTal 4y ago

Presumably "organic" is here used in its figurative meaning of "[chaotic] result of a natural process", rather than "carbon-based compound".

nkrisc 4y ago

> edit: And calling film grain "organic" is a bit of a stretch, it's silver halide crystals. I thought it was super obvious they didn’t mean organic in the chemical sense.

cratermoon 4y ago

And yet, film developers like phenidone, hydroquinone, and metol are all organic compounds. And once developed, there are no halogens left, it's metallic silver.