An image that looks perfect on screen can become grainy in print if you do not understand colour resolution and file formats. As a media designer you must be able to choose the right colour space and format for each task.
§RGB and CMYK
RGB is an additive color space based on light (red, green, blue) and is used for screens. CMYK is a subtractive color space based on printing inks (cyan, magenta, yellow and black/key) and is used for printing. Some bright, luminous RGB colors cannot be rendered accurately in CMYK, and therefore you must work in the correct color space from the start and check how colors behave when converting.
- 01Work in RGB for digital deliveries such as web, app and video.
- 02Work in CMYK when the final product will be printed.
- 03Be aware that RGB→CMYK conversion can dampen very saturated colours.
- 04Use correct colour profile and clarify the printer's requirements in advance.
§Resolution and image size
Resolution indicates how many image points (pixels) are packed into a given area. Print requires higher resolution than screen because the eye looks more closely at printed details. An image cannot be made sharper by enlarging it — the missing information cannot be invented. Therefore, sufficient resolution must be ensured already when photographing or obtaining material.
§Raster vs. vector
Raster images (bitmap) are made up of pixels and are suited to photographs. Vector graphics are made up of mathematically described lines and surfaces and can be scaled freely without losing sharpness – that's why vector is used for logos, icons and illustrations that need to be reproduced at many sizes.
| Property | Raster | Vector |
|---|---|---|
| Built from | Pixels | Lines and areas (mathematical) |
| Best for | Photographs | Logos, icons, illustrations |
| Scaling | Loses sharpness with magnification | Scales freely without loss |
§Selection of file format
The file format is chosen by purpose. For web, compressed raster formats for photos and vector format for sharp graphic elements are typically used; for print, it is often delivered in a print-ready, high-resolution format with correct colour profiles. An editable working format is always saved alongside the finished export format so you can correct in the original later.
§Copyright and source material
Images, fonts and illustrations are protected by copyright. Only use material you have permission to use, and keep track of licenses and credits. It is part of professional craftsmanship — not just a formality.