Use of images
Image resolution
Ensure that the image resolution is sufficient for printing. Ideally the image resolution is twice the screen line. The screen line ruling is determined according to the used paper and press.
Guideline values for image resolution:
Print Method |
Paper Coating |
Resolution ppi |
Screen ruling lpi (lcm) |
Sheetfed |
Coated |
350 |
175 (70) |
Sheetfed |
Uncoated |
300 |
150 (60) |
Preparing the images with resolution 350 ppi, you ensure the resolution is sufficient for all printing. If you know which paper will be used, you can surely prepare the images to a lower resolution. As a benefit you’ll get a smaller file size, otherwise it has no importance.
NOTE!
Enlarging the image in a layout reduces the effective resolution. E.g. after enlarging a 350 ppi image to 200%, the real resolution is no more than 175 ppi.
Total Ink Coverage in CMYK images
The total sum, in percentage, of partial colours in the darker areas of an image are determined according to the paper and press used. In addition, this value is also affected by any UCR or GCR function that is used. Today, the ICC profiles include this information. By using a proper profile in colour separtaion a correct TIC (Total Ink Coverage) value is determined automatically into the images.
The total ink values used for standard output profiles are described in the table below. The total ink values in the table – and the functionality of the profiles – are based on the printing according the values defined in standard.