Saturday, March 8, 2014

Noise vs. Grain

In the same forum (Fine Art Photographers) someone said they liked Noise as it gave them that grainy look of film. My reply. 
On the grainy look….
 
OK lets get this clear, digital noise is NOT grain. It doesn’t even approximate grain.
 
In traditional B&W film grain is caused by the size of the silver crystals in the film itself. It is what creates the image in the form of black on the negative. These almost invisibly small crystals take on the look of grain when enlarged. This ‘grain’ is prized by many photographers even to this day and it still plays a large role in the Fine Art photography world of collectors.
 
B&W grain is uniform based on the film type. Different films had different grains, some finer, some larger but generally always uniform throughout the entire picture in the whites, mid tones and blacks (but not in the blown out areas).
 
Photographers usually likes a specific film for the grain (or lack thereof) and often shot all their work (or sometime specific projects) with a specific film. The reason for this is because of consistency. They could get very consistent repetitive results if they used the same film and the same processes. This is important when creating a project or body of work.
 
Digital noise on the other hand varies greatly from picture to picture based on not just the ISO setting used but on the scene itself, the amount of light and dark areas, whether the scene is back lit or not and even on if the exposure is perfect or not. Add to the fact the longer exposures change the whole equation as does temperature. The hotter it is you usually end up with more noise.
 
Another issue with noise is that it varies not just from picture to picture but within a picture itself. Each area light/dark will have differing amounts of noise. And this noise is not shaped and randomized like ‘silver crystals’ but takes on blotchy areas and worse (or better if that’s what you want) takes on colours.
 
It is this lack of consistency that can make your image not work well together as a unified body of work. Typically fine art photographers work hard at capturing the perfect images they require with the least amount of noise possible. Then, they will remove any noise present and finally they will add grain either in programs like Photoshop or they will use a program or plugin like NIK Silver Efex Pro. Using this process, you can have complete control (and repeatable control) over the look, feel and size of the grain and you can make it consistent within all your images.
 
On the other hand if you like the look of ‘noise’ then by all means go for it! It has its own unique qualities that may work with your images. Just remember that’s it not grain.


© 2014 Francois Cleroux
Version 1.00 - February 2014

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I value thoughtful comments and suggestions. If you like or dislike this post, please let me know. If you have any ideas or suggestion, comments or corrections (I do make mistakes) please also let me know. Thanks.

- Francois Cleroux