Grain

>>3136401
grain is inherent with digital cameras as the smallest resolution points can either be on or off, just like with film. nothing can change this. you can try to edit the grain a little like smoothing it out but that will fuck up microtextures obviously so it will reduce the image quality.

>>3136436
So it appears that, by that explanation, the only way to remove grain is by adding megapixels and making the "grain" much smaller(?)

>>3136401
When a signal is amplified, you will get noise.

>>3136452
well it's not that easy. sure theoretically you could try to make the sensor resolution fine enough so that your eye cant recognize them anymore. but even with todays resolutions, most lenses cant even provide a sufficient optical resolution to fully benefit from it. if you want to change that, you need to build larger optics and use larger sensors/film to increase the image quality until you are satisfied.

but pretty sure it's not the number of megapixels that bothers you; probably not even the optical resolution of your glass since if that would be unbearable you should find any classical photography disgusting. maybe you just hate the character of your medium, for example the heavy banding and regular pixel grid in your picture. you can switch over to film in this case. or wait for the next digital advance where pixel no longer are organized in a grid like with the screens of some modern smartphones or much higher bit-depths become standard, whatever.

>>3136401
Noise on digital cameras exists for a number of reasons. First and foremost, a sensor is basically charged with electricity all the time that it's active, which causes heat buildup (thermal noise), and general signal interface, being an analog device, sensors are in fact sensitive to electrical interference.
Next there are various aspects of physics like shot noise that come simply from the interaction of the photons and sensor, which causes a fine grain to form even in well-exposed areas.
Last but not least, there will be noise (more like artifacts really) that exists as a by-product of the fact that sensors don't capture accurate data for each pixel position, even with a good debayering algorithm, so some amount of graininess of the original pixel structure will always remain.
Some sensors produced by Sony have markedly lower noise and higher dynamic range because they developed the technology to read data off a sensor right on the sensor itself. Essentially, the faster you can measure the photon level and transform it into integrally secure digital data, the less noise you will get from interference sources.

>>3136436
This is wrong, the sensor wells are analog devices and can measure out an arbitrary range of values (although limited by full-well capacity), ADC transformation then simplifies this form to a range of 16,384 values with your typical 14-bit camera electronics.
The so-called "analog" film is actually the opposite way around in this aspect, since each grain of film can be polarized in only one of two positions. It's only through the combination of billions of film grains that dithering makes it seem as though there's a continuous tone. This is why film benefits significantly more from increased area size vs digital (sensor wells will accurately record tone at any pixel pitch), and also why film loses high-frequency contrast at higher resolutions, whereas sensor maintain maximum contrast up to the nyquist frequency.

>>3136452
Digital noise is, for the most part, a global variable, so you actually want pixels to be as large as possible to capture more light. At the same time, having more pixels does generally hide more of the "digital edge" that cameras tend to have at lower resolution, because you're getting a more accurate color sampling for any giving captured area.
The key then is to find a balance where you cram as many pixels in as you can, so long as it doesn't come as a significant detriment to noise and dynamic range. For instance, the sensors in cameras like the Nikon D810 and Sony A7RII and Pentax 645Z are sufficiently advanced that they wouldn't necessarily have benefited from having larger pixels - after a point you become limited technologically with regards to how much of an improvement you can get just by making pixels bigger. Without better readout or ADC they won't get more than maybe 1/2 stop better DR even if you halved the resolution. At this point it's better simply to keep the resolution decently high and take advantage of oversampling rather than worrying about noise and DR, which is already exceptional on these models as it is - if you're having issues even with that kind of hardware, you're probably doing something wrong.