Print Quality
Image and print quality are largely dependent on the following factors:

1. Printer resolution
2. Ink properties
3. Paper suitability

1. Printer resolution
The resolution of a printer is specified in dots per inch (dpi). This means the number of dots produced in a vertical or horizontal inch.
Printing several drops of ink one on top of the other produces the required colours and shadings for each individual pixel. The image to be printed is produced by the printing colours (cyan, magenta, yellow, black) when observed from a distance. Current photo printers have a resolution of up to 5,760 dpi and use droplet sizes of less than 2 pl. To enlarge the colour space, manufacturers often use extra colours in addition to the basic colours of cyan (C), magenta (M), yellow (Y) and black (K). Examples include light cyan (LC), light magenta (LM), orange (O), green (G), blue (B) and special colours such as matt black or photo black.

2. Ink properties
Ink manufacturers have developed different inks to cover the wide variety of applications. A distinction is made between water-, solvent- and oil-based inks.

Only water-based inks are used in the desktop sector. They are divided into dye inks and pigment inks (also called UV inks or UltraChrome® inks). Finer nuances of colour can be achieved with dye inks that with pigment inks. On the other hand, dye inks are not as resistant to light and ageing. In contrast, pigment inks are more resistant to environmental influences such as light, ozone and water. They are therefore preferred for large-format printing for outdoor applications.

In the case of solvent-based ink an aggressive solvent is used as the carrier for the colourants. This solvent evaporates during printing and noxious vapours can occur. Extraction is required in many cases. The advantage of these inks is that they adhere to a wide range of materials (banners, fabric, wood, etc.). Additional pre-treatment in the form of a special ink-receptive coating, for example, is not required.

So-called oil-based ink plays a relatively minor roll. In this case oil is used as the ink carrier. This odourless ink offers the advantage of being more resistant to water and light than water-based inks.
Oil-based inks are only used for large-format printing on equipment made by Xerox® and Seiko®.


3. Paper suitability
The suitability of the paper used has a major impact on the quality of the printing. In the case of uncoated natural papers the ink can penetrate right into the cellulose fibres. This allows the ink to spread out of control along the fibre, resulting in a fuzzy print image. What is more, such papers can only absorb a small amount of ink. If they absorb too much, they have a tendency to cockle.
To counteract this effect, natural papers are given a special ink-receptive coating. Unlike with natural paper, the ink is unable to penetrate the cellulose because it is fixed in the ink-receptive coating. This makes it possible to produce print images with impressive sharpness and brilliant colours.
Different formulations and application weights for the ink-receptive coating control factors such as the surface gloss, smoothness, whiteness, stability and ink absorption of the print medium.
Cast-coated inkjet media win customers over with their high-gloss surface. Mainly used in desktop printing with water-based dye inks, they deliver photo realistic printing that bears comparison with traditional photo papers.
A further development is represented by what are called photo papers. Available in a silk matt, lustre or gloss finish, these media have been specially developed for photo printing. They are superb for both desktop and large-format inkjet printing. The microporous surface coating guarantees optimum compatibility with dye and pigment inks, extremely fast drying and excellent wipe and water resistance. The special PE coating on front and back offers optimum flatness even with high inking levels and the unique haptics of an analogue photo paper.