Screening method and apparatus for use in intaglio printing
The present application provides a screen method for intaglio printing, comprising: dividing multiple classes of regions according to a brightness range; and generating screen dots with various screen patterns for the grouped classes of regions. The present application also provides a screen device for intaglio printing, comprising: a dividing module configured to group multiple classes of regions according to the brightness range; and a generating module configured to generate screen dots with various screen patterns for the grouped classes of regions. Since multiple kinds of screen patterns are applied in the technical solutions in present application, the problem, i.e., water ripple will occur in the prior art, may be addressed, so as to improve the quality of printing.
1. A screening device for use in intaglio printing, comprising:
a dividing module configured to divide tonal zones to be printed into a plurality of classes of regions according to the brightness ranges; and
a generating module configured to generate screen dots with various screen patterns for the classes of regions,
wherein, the dividing module sets a region having brightness in [0, Per 1 ], a region having brightness in a light tone region[Per 1 , Per 2 ], a region having brightness in a light tone region [Per 2 , Per 3 ] and a region having brightness in [Per 2 , 1] as a light tone region, a light tone-mid tone region, a mid tone-dark tone region and a dark tone region, respectively,
and wherein Per 1 =0.25, Per 2 =0.5 and Per 3 =0.8.
2. The device according to claim 1 , wherein the generating module comprises:
a light tone module configured to generate screen dots with a first screen pattern in the light tone region, wherein, respective unit space for each screen dot in the light tone region is generated by the light tone module, and centre of each screen dot is set as an original point, x and y indicate coordinates in the unit space for the corresponding screen dot, so that the light tone module sets f (x,y)=max(|x|,|y|), wherein, {(x,y)∥x|≦Per 1 , |y|≦Per 1 }.
3. The device according to claim 1 , wherein the generating module comprises:
a light tone-mid tone module configured to generate screen dots with a second screen pattern in the light tone-mid tone region, wherein, the light tone-mid tone module generates respective unit space for each screen dot in the light tone-mid tone region, and wherein, centre of each screen dot is set as an original point, x and y indicate coordinates in the unit space for the corresponding screen dot, so that the light tone-mid tone module sets f (x,y)=0.5+0.3 *t/n, wherein, n is integer greater than 1, and t ε[0,1].
4. The device according to claim 1 , wherein the generating module comprises:
a mid tone-dark tone module configured to generate screen dots with a third screen pattern in the mid tone-dark tone region, wherein, the mid tone-dark tone module generates respective unit space for each screen dot in the mid tone-dark tone region, and wherein, centre of each screen dot is set as an original point, x and y indicate coordinates in the unit space for corresponding screen dot, so that the mid tone-dark tone module sets f (x,y)=0.5+0.3*t/n, wherein, n is integer greater than 1, and t ε[0,1].
5. The device according to claim 1 , wherein the generating module comprises:
a dark tone module configured to generate screen dots with a fourth screen pattern in the dark tone region, wherein, the dark tone module generates respective unit space for each screen dot in the dark tone region, and wherein, centre of each screen dot is set as an original point, x and y indicate coordinates in the unit space for corresponding screen dot, so that the dark tone module sets f (x,y)=1−0.2*t/n, wherein, n is integer greater than 1, and t ε[0,1].