Color Images

• File format: Save your images in either TIFF, EPS or DCS format. Avoid other formats like PICT, WMF, JPG or BMP. The layout application may support these formats but their proper conversion to PostScript data while printing is never guaranteed.
• QuarkXPress and TIFF: When placing TIFF images in QuarkXPress (Mac or PC) make sure to never have the background color of the picture box set to “none”. The image below shows what can happen if the background is set to ‘none’: either there is staircasing (jagged edges) at the edges of the image or white areas within the image simply vanish.

• Resolution: Make sure images have the correct size and resolution while scanning them. The final resolution of color pictures should be (screenruling x scale x 2). The “2” is a qualityfactor that can vary between 1.5 and 2.5 depending on your quality needs and the subject of the image. So if you scan a photograph and want to enlarge it 300 percent in the layout application and your publication is printed at 150 lpi, the image should be scanned at (150 x 3 x 2) or 900 dpi.
• Size: Never enlarge or reduce images more than 20 percent in your layout application. Enlarging them will lead to pixelization and staircasing. Reducing them too much will lead to a loss in sharpness and contrast.