| Darkroom: |
Light tight room used for processing and printing. It usually incorporates safe lighting suitable for the materials in use. |
| Deadstick: |
Describes a descent and landing with engine(s) shut down and propeller(s) stopped. |
| Definition: |
Subjective term for the clarity of a negative or print. |
| Delta: |
Stands for the letter D in the phonetic alphabet. |
| Depth of field: |
Distance between the nearest point and the farthest point in the subject which is perceived as acceptable sharp along a common image plane. |
| Descend: |
To come down under control from a higher to a lower altitude. |
| Descent: |
The action carried out in flying an aircraft from a higher to lower altitude. |
| Development: |
Process of converting exposed silver halides (negative or positive film) into visible images |
| Dew Point: |
The temperature to which the air must be cooled for water vapor to condense and form fog or clouds. |
| Differential focusing: |
Setting the camera controls to produce minimum depth of field, so that image sharpness is limited to a particular subject element. |
| Digital camera: |
A camera that captures the photo not on film, but in an electronic imaging sensor that takes the place of film. |
| Digitize: |
The proccess of converting or encoding an image or data that is represented in analog form into digital information of X and Y values.
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| Disc Area: |
The area swept by the blades of helicopter rotor. This is a circle with its center at the hub axis and a radius of the longest blade length. |
| Dodging: |
Selectively lightening part of a photo with an image editing program. |
| Doppler: |
The Doppler effect (or shift) is the change in frequency of light, radio or sound waves when source and receiver are in relative motion. |
| Doppler Radar: |
A type of weather radar that determines whether atmospheric motion is toward or away from the radar. It determines the intensity of rainfall and uses the Doppler effect to measure the velocity of droplets in the atmosphere. |
| Dots per inch: |
Also called DPI, the resolution, or number of pixels or pieces of information per inch, of a graphic or image. A higher DPI will be more precise and therefore produce a sharper image. High DPIs also mean large file sizes and so sharpness must be balanced |
| Downdraft: |
A column of generally cool air that rapidly sinks to the ground, usually accompanied by precipitation as in a shower or thunderstorm. |
| Downwind leg: |
A flight path parallel to the landing runway in the opposite direction of landing. |
| Drag: |
The force that resists the motion of the aircraft through the air. One type of drag is caused by air molecules. As the aircraft flies through the molecules, they resist the motion of the aircraft. This resistance is due to friction between the air molecul |
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