is graininess in a picture the same thing as noise?

Answer 1

Well, not really. If you are looking at a print from film, there IS no noise, but there can be plenty of grain.

Here's a scan of a print from film and I added fake grain from Photoshop. It is actually a decent rendering of what real "grain" looks like: http://www.flickr.com/photos/samfeinstein/774534298/ Grain in film comes from the size of the photosensitive crystals. If they are big enough, they are visible in the print. The grain comes from the negative and not the paper, by the way.

"Grain" in digital may be noise that looks sort of like those crystals. Here's an extreme example: http://www.flickr.com/photos/samfeinstein/842992586/ Read the caption and then click "All sizes" and "Original" to see the digital version of grain. This is noise that looks kind of like film grain.

So, it's a matter of whether you choose to call digital noise "grain" or not. It's not really grain, because there are no crystals ("grains") but it mimics grain in film.

Maybe I can explain why you see grain in some film and not others, but it will be short and simplified because my brain is fading. Film has crystals deposited on a base (the actual film itself) and held in place by a layer of "glue" called emulsion. These crystals (in black and white film - not to complicate things...) are light sensitive. If a photon strikes an individual crystal, it alters it chemically. When you develop and fix the film, that crystal will be stripped from the film base. If you have a lot of microscopically tiny crystals, it takes more light to create a useful image. This is how low ISO films are made. If you have fewer crystals, they will need to be larger in order not to leave gaps on the film, but this means there is a greater chance for each individual crystal to get struck by a passing photon so the film is more sensitive to light. This is how higher ISO films are made. The thing is, while the film is more sensitive to light and can be used in a darker situation, those larger crystals are big enough to show up when you pass light through the film to make a print on paper. This is why "faster" films have larger grain in the prints. The grain on the faster films is actually larger than it is on the slower films so it shows up more.

Digital noise comes from the "bleed over" of the boosted signal from one photodiode into the "realm" of its neighbors. You might say that it is analogous to distortion in a musical recording when you turn the volume up to loud. Or, you can compare it to clipping of the source material if you have the gain in the pre-amp too high, but this might be too esoteric for this discussion.

The more you boost the signal out from the sensor, which is all you are doing by using a higher ISO in a digital camera, the more interference it gives to the signal of the adjacent pixels (photodiodes) and the more digital noise is created. Noise is an artifact of the amplification process; something that is not really there. Grain is actually present in the film.

Was that rambling enough for you? If I clouded the issue, you have your choice of running my answer through the hypo for an extra minute of viewing it through a polarizing filter. Either one might help...

Answer 2

Grain and Noise are two different things, but are basically the same.

As to a answer posted above, Grain is not on the paper. Grain is on the film. When you get high ISO film speeds, like ISO 1600 or 6400, the silver halide crystals in the emulsion on the film grow large; this is to capture more light. The higher the ISO, the larger the crystals, the more grain there will be. The lower the ISO-50, 100, 200, 400-the less grain will be apparent.

Noise is the same way, sometimes referred to as digital noise. Noise is the sensor mimicking film. It basically does the same thing as film does when the ISO is raised. It is often said, though, that film has a more appealing grain when compared to digital cameras. With digital cameras, it seems more annoying, and causes lack of detail.

Hope this helped.

Answer 3

Not exactly though the effect is similar
.
Noise can be used in Digital imaging to simulate grain that is inherent within Film stock.

Essential;y film is made up from Silver salt crystals in a gelatine emulsion spread upon a flexible or rigid base.

Films with a low ISA (ASA) e.g. < 100 ISA have fine grain which seldom manifests itself in the print. Such films are called 'slow films'.

The faster films with a film speed > 400 ISA have larger, more light responsive, crystals.

The variation in crystal size is called the grain size.

The larger grains of the slower films, when printed correctly
through a high definition lens such as a Rodagon can be seen sharply focused in a print.

They only give a fuzzy or unfocussed effect when badly used or in low quality equipment.

When used correctly many high impact prints have been made utilizing the grain effect of film stock .

It is the ability of a lens to bring the individual crystal 'grains' of the film into sharp focus, at the same time, across the diagonals of the film negative, that is in a large part the factor determining the quality of a lens.

In digital photography, noise introduced at the image editing stage, within the computer can be used to give a similar, and equally impressive display image.

Hope this helps.

Answer 4

Yes and no. Grain and noise are produced for the same reason. Noise is produced because the photosites in a digital are not identical. Grain is produced because the silver halide crystals in the film are not identical to each other.

The difference between grain and noise is they do look different. The noise produced by Canon cameras are easily identified as digital noise because of the colour variation between each pixel. Nikon noise is more like film grain because there's is minimal colour variation and mainly luminance variation like film grain.

Answer 5

strictly speaking, no.
graininess is when you use iso 500 or higher film. noise is the color speckles in digital pictures.
although for common use, grain is just one type of noise, along with the jpeg artifact

Answer 6

I would say that the graininess means the lack of clarity and sharpness.

Answer 7

Yeah

Answer 8

dr.sam gave you a long answer, but a very correct and precise answer, what he sez is rite.

Answer 9

i vote for dr sam

a

Answer 10

No, the grain is in the paper the photo is printed on.
Although this grain pattern is very small, it doesen't
show up unless you over enlarge the photo.