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The terms may sound familiar to you; maybe you have even experimented with some of them in different photo editing applications. You intuitively have an idea of what they mean but if anybody asked you to define them, you would struggle. If that's the case, this little glossary will help you clarify some of the basic notions relating to digital photography by providing simple and clear definitions.
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1. Alpha Channel – A mask that allows the user to set different levels of transparency for an image.
2. Anti-aliasing – A technique that makes the edges of an object appear smooth by inserting intermediate pixels in grey shades between that object and the background.
3. Aspect Ratio – A formula that divides the width of an image by its height. Examples of aspect ratios used in photography are 4:3, 3:2, 1:1 (square). If you tick the Keep/Maintain the aspect ratio box when you resize a digital image, you only have to fill in one field (either the width or the height), as the program will automatically generate the other one according to the formula.
4. Background – Part of an image that lies behind the objects in the foreground.
5. Balance – The property of all the visual elements in a photo to be in harmony with one another and create a pleasant effect to the eye. In achieving the balance, the photographer has to take into account several properties such as brightness, contrast, saturation, etc.
6. Composition - The technique of arranging the visual elements in a photograph in such a way that they are pleasing to the eye. When composing a picture, the photographer has to take into account several principles and elements such as focus, viewpoint, lighting, etc.
7. Contrast – The difference in color and brightness between objects. We talk about a low contrast when the difference between the visual objects is smaller and a high contrast when this difference is bigger. A higher contrast makes it easier for us to distinguish the visual elements in a photo. (See example below).
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8. Cropping – A process that involves selecting a part of an image and deleting all the rest.
9. Digital zoom – Making the subject appear closer by using the digital zoom feature on the digital camera. This has the same effect as cropping and enlarging an image on the computer.
10. Foreground – Part of an image that is closer to the viewer (as opposed to background) and usually includes the point of interest.
11. Hue – The main property of a color, the one that makes it what it is. The hue is the actual color we refer to in everyday speech. Red, blue, orange, green are all hues. Hues can be divided into two main categories: warm and cool.
12. Lighting – An element of composition that refers to using light and shadow in such a way that they draw the viewer's attention to the focus of the image. The distribution of light can emphasize the main point of interest. Shadows can add depth to an object, bring out its form or add a 3-D effect.
13. Optical zoom – Making the subject appear closer by using the lens of the camera.
14. Pixel – The smallest unit of a digital image. The term "pixel" is a shortening for "Picture Element". It is usually invisible for the eye but it can become visible when the image is zoomed in. (See Pixelation) Digital images can be measured in pixels.
15. Pixelation – Displaying an image at such a large size that the individual pixels become visible to the viewer. It is what happens when you zoom in a photo.
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16. Point of interest (also called centre of interest) – The main element in a picture, the visual point that attracts the eye of the viewer. A picture without a point of interest can be puzzling or confusing. It can be placed in the centre of the image but experts recommend positioning it at one of the intersections of the imaginary vertical and horizontal lines that divide the image into thirds.
17. Resolution – The number of pixels that can be displayed in an image. A higher resolution means a sharper and clearer picture, displaying more details.
18. RGB – (Red Green Blue) A color model that consists in mixing the three above-mentioned primary colors together in different quantities to form a new color.
19. Saturation - The amount of grey that can be found in a particular color. The less grey we have in a color, the more saturated that color is. We call bright colors highly saturated. On the other hand, an example of complete unsaturation is a black and white image (which is made up almost entirely of different shades of grey).
20. Tone – The intensity of lightness or darkness in a color. Every color has a large range of tones going from very light to very dark. So when we say dark blue, dark refers to the tone property of the color while blue refers to the hue property.
21. Viewpoint – The position of the camera in relation to the subject. The photographer should look at the subject from different viewpoints in order to get a better perspective.