Rosettes in Print – not just for winners!

In four colour printing, images are all made up of halftone dots – one for each of the colours (CMYK). It occurs when 3 or more are all overlaid at angles to create what you can see close up, as a moire pattern, or rosette. Below you can see this represented by Wikipedia with multiple screen angles.

Screen Angles

Screen Angles courtesy of Wikipedia

There are 2 kinds of rosette that can be created:

1) Dot Centred

Dot Centered CMK Pattern

Dot Centered CMK Pattern

Called dot centered or closed centered, as there’s a dot in the centre!

Details of the dot-centered rosettes are:
• They show a less visible pattern than clear centered ones
• Have individual dots that land on top of one another – reducing chroma/gamut slightly
• Produce colour slightly differently than clear-centered rosettes
• Are more popular with low screen frequencies – 100 lpi and lower
• They tend to lose shadow detail
• Slight mis-registration causes significant colour shift

2) Clear Centered

Clear Centered CMK pattern

Clear Centered CMK pattern

Clear centered or open centered pattern, as there’s no dot in the centre of this rosette.

Details of the clear-centered rosettes are:
• They show a more visible pattern than dot centered ones
• Look slightly lighter due to more paper showing between dots
• Produce color slightly differently than dot-centered rosettes
• Tend to preserve shadow detail better
• resist color shifts better when slight misregistration occurs
• are more popular with high screen frequencies – 150 lpi and higher

Hope you found that interesting. If you need any more information or want to get in touch, call us on 0844 272 9109 or email [email protected]

 

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