KB376398309: Imaging Engine - Why can the scum dot removal be different for the View files

Question

Why can the scum dot removal be different for View files compared to the LEN(X) file?

For example: The view file removes the 'smaller' WSI dots, while the LENX keeps them (as when boosted > smallest mindot, so should not be removed by Dot Cleanup)

Answer

Note that because of a different screen is used for the 'view' version, output can show differences also at other tones because of difference in scum dots.

The 'view' version of a screen is resulting in different scum dots compared to ripping with the real crystal screen which is using Pixel+.

This is a 'known limitation' for view files: dot cleanup is not exactly the same as LENX cleanup. See in the screenshot below; on the left is the LENX file with Crystal screen (using Pixel+), in the middle is the view file with an AM screen.

Technical background

View files do not use P+ dots and therefore cleanup of view files will be different when handling a cluster of pixels that contain isolated pixels.

On the LEN file, when in a cluster of pixels a pixel is isolated (no left/right, top/bot neighbor pixel), that pixel is considered as a boosting pixel. When there are 3 or more of such pixels, the cluster will not be cleaned up. Below screenshot is another example.