Agfa Gevaert Nv

Agfa-Gevaert

Jan Van Cauwenberge

Paul A Delabastita

Johan Hubert Van Hunsel

Jacobus Herman Bosschaerts

Katrien Daels

Johan Vanhunsel

A visual control strip for imageable media such as a printing plate, a photographic film or a printable substrate is described wherein the visual control strip is to be applied to the imageable medium. The control strip includes a plurality of first control fields having differing grey tone values which are relatively insensitive to the processing variables which influence the size of the spots or dots produced on the imaged medium. The control strip also includes at least one second control field which is relatively sensitive to these process variables. The second control field is located immediately adjacent to the first insensitive control fields for ease of comparison. The second sensitive control field has a target grey tone value which may typically be 25%, 50% or 75%. To improve assessment of exposure parameters, the insensitive fields are completely surrounded by a sensitive field or vice versa. Methods of using the strip are also described for both traditional or photomechanical and digital reproduction methods.

Visual control strip for imageable media

A method for generating a screened reproduction of a multiple tone image comprises the steps of autotypical or amplitude modulation screening the multiple tone image to obtain screened data representing tones of the multiple tone image in terms of halftone dots; reproducing the halftone dots on an imaging element by means of a scan-wise exposure by means of a laser or a LED, wherein in extreme regions of the tone scale the shape of the halftone dots is compact, characterized in that the halftone dots have a ratio of peripheral length to surface area which is minimal.

Autotypical screening with optimised dotshape

In order to improve the printability of a periodic halftone screen, the amount of growth of the halftone dots in a halftone screen is modulated as a function of tone in a tone selective way that is different for at least two halftone dots.

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Zottegem, Belgium

Jan Van Cauwenberge