iMedia R081 Pre Production Skills
3.2: describe the properties and limitations of file formats for still images
3.2: describe the properties and limitations of file formats for still images
| Keyword | Definition |
|---|---|
| bitmap | An image made up of individual pixels |
| colour palette | The number of colours used in the image |
| compression | Technique used to reduce the file size of an image |
| DPI | A measure of quality calculated by the number of dots or pixels in a line that's 1 inch long. |
| file format | The type of file that has been saved |
| file size | The number of bytes used to store the image. |
| GIF | File format that uses lossy compression to reduce file size. Great for logos or cartoons with a limited number of colours but not suitable for photos. Supports animation and transparency. |
| height | The number of pixels in each column up/down an image |
| JPG | File format that uses lossy compression to reduce file size. Great for photos or use on the internet but doesn't support transparency and reduces the number of colours and detail available. |
| limitations | Weaknesses of a particular file format |
| File format that combines images and text in a way that can be easily distributed without needing particular fonts or software to be installed. | |
| PNG | File format that uses lossless compression or no compression for high quality images. Large file size but supports full or partial transparency. Suitable for diagrams or logos but not ideal for photos due to large file size. |
| PSD | File format used by Photoshop that stores layers and effects separately so images can be easily edited providing that you have Photoshop installed. Very large file size. |
| still image | A picture rather than a video or animation |
| transparency | Whether or not parts of an image can be completely or partially see through |
| vector | An image made up of shapes, colours and patterns |
| width | The number of pixels in each row across an image |
