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- Is a unit of measurement of light wavelength. A nanometer is one million of a millimeter.
- A time measurement equal to one-billionth of a second.
- ND Filter or Neutral Density Filter
- A filter that attenuates light evenly over the visible light spectrum. It reduces the light entering a lens, thus forcing the iris to open to its maximum.
- Near ultraviolet
- Are wavelength from about 400nm down to 250nm. Most photographic emulsions are sensitive to this range of bands.
- Nearest neighbor
- Type of interpolation in which the value of the new pixel is an average of the neighboring pixels. Quick and dirty interpolation that gives rather ragged results.
- A photographic image which tonalities and colours are reversed from the original scene. Usually the film negative is used to make a positive print.
- Negative carrier
- A frame that holds a negative flat in an enlarger.
- Neutral density filter
- Describes a gray camera filter which has a equal opacity to all colours of the spectrum and so does not affect the colours in the final image. It is used to reduce the amount of light entering the camera when apertures or shutter must remain constant.
- Newton rings
- A series of concentric circles that appear on a scanned image when a thin layer of air exists between the glass scanner bed and the image being scanned. Newton rings appear when light waves are reflected from both top and bottom surfaces of the air between the glass and the image, interfering with the resulting scan.
- Nickel cadmium (NiCad)
- Rechargeable batteries that use an alkaline electrolyte. They have a longer life than non-rechargeable batteries. NiCad batteries have a memory, so they need to be run all the way down before recharging. Otherwise, they will begin to run out of power sooner.
- Nickel metal hydride (NiMH)
- A rechargeable battery that lasts longer than a NiCad and has no memory, so it is easier to manage.
- Noise can be summarized as the visible effects of an electronic error (or interference) in the final image from a digital camera. Noise is a function of how well the sensor (CCD/CMOS) and digital signal processing systems inside the digital camera are prone to and can cope with or remove these errors (or interference). Visible noise in a digital image is often affected by temperature (high worse, low better) and sensitivity (high worse, low better). Some cameras exhibit almost no noise and some a lot and all the time. It's certainly been the challenge of digital camera developers to reduce noise and produce a "cleaner" image, and indeed some recent digital cameras are improving this situation greatly, allowing for higher and higher ISO's to be used without too much noise. Noise can also affect certain colour channels more than others, this is because a typical digital camera sensor (CCD/CMOS) is more sensitive to certain primary colours than others (often sensors are less sensitive to blue light) and so to compensate, these channels are amplified more than the others. Noise is also often amplified by the JPEG compression algorithm which reacts badly to a very noisy image (often introducing hue errors which weren't in the original noisy image). There are several techniques for cleaning a noisy image, and several products which have been developed to specifically perform this task. Long Exposure "Stuck Pixels“ - Another type of noise often referred to as "stuck pixels" or "hot pixels" occurs only with long exposures (1-2 seconds or more) and appear as fixed coloured dots (slightly larger than a single pixel). These stuck pixels can be fairly successfully removed by taking a "dark frame" either before or after the main shot and subtracting this from the original shot, this technique is detailed innoise reduction.
- Image compression without loss of quality.
- Normal lens
- A lens with a focal length approximately the same as the diagonal measurement of the film being used. This produces an image that approximates the same angle of view and perspective of the human eye. For a 35mm camera, the 50mm lens is considered normal.
- Notching code
- Notches cut in the margin of sheet film so that the type of film and its emulsion side can be identified in the dark.