Patterns appear in CTP highlight dots

[nagtype]

Using Nexus 7.5r11 to for computer-to-plate output to a Creo Thermoflex at 2400 dpi. Lately (past 4-5 months) have been seeing patterns, lines, etc appearing in highlight areas 1%-6% especially in Magenta (82.5 degree). 1-bit TIFFs may or may not have the pattern in them, Artwork Sys. says no but without Dot Spy we can't be sure. Our old plates from late 2003-early 2004 definitely did NOT have these patterns in them. Anyone experiencing the same problem?

[knvb]

Have you looked at the thermaflex, we have seen patterns from the swathing and/or laser. Does DotSpy show these patterns?

Photoshop CS will open 1-bit tifs

Bman

[Kristian]

What version of ArtPro are you using??

If you are using Version 8 you need to double check you 'Noise' values, by default in ArtPro 8 rev1-4 this is 5% which causes problems with the highlight dot.

They have changed this to be 1% (Same as ArtPro 7.5) but you still need to double check before printing anything.

The noise values are found under the Flattening options in the preferences. If this isnt the issue then im not too sure.

[Sack]

We had same problem outputing film on the Dolev 800v imagesetter. Particularly noticable below 3% @ 133lpi on Magenta. Everything looked fine in Dotspy, and RasterBlaster preview.... Found it was due to a faulty I/O board in the Dolev. Once replaced, lines gone.