Corrupt software on the RIP
At one of our sites, a 'Sethalftone' error was caused by
corrupted screenfilter software on a Star 800 RIP. Simply
reinstalling all of the RIPs bootfiles solved the error.
Incorrect configuration of the RIP
When using several 16-bit Agfa Balanced Screens or
several halftone screens from the Agfa Balanced Screening
Option Kit (Flexo, Gravure, etc.) on an Agfa Taipan 2.02 or
3.01 a PostScript error "limitcheck", offending command
"sethalftone" may occur. This problem can be solved by
changing some buffersettings in the Taipan Tuner
application.
Insufficient memory
Sethalftone errors can also be caused by insufficient
free space on the harddisk of the RIP. Funnily enough this
can be more of a problem when you try to output very coarse
screenrulings like 5 lines per inch. This can cause
"limitcheck" errors, offending command "sethalftone" because
the RIP needs too much memory to calculate all the
screentiles for such large dots.
There are several work-arounds for this kind of problem:
- Lower the resolution of the RIP
- Allow the RIP to use more memory. This is often easy
on software RIPs like the Agfa Viper RIP.
- Try cleaning up the RIP a bit to solve the error.
- The following PostScript code may solve the problem
on Agfa hardware RIPs
Simply download the code to the RIP. It enlarges internal
buffers. I do not know whether this code is still valid for
current RIPs. The number 20000000 in the code represents the
size of the cache in bytes. You can modify this value
true 0 startjob
<< /MaxScreenItem 20000000 >>
setuserparams
<< /MaxScreenStorage 20000000 >>
setsystemparams
Using PhotoShop as a work-around
Since "sethalftone" errors only occur when the Rip has to
rasterize a page, it is sometimes possible to use the
"Rasterize" filter of PhotoShop to rasterize elements of the
page, instead of relying on the RIP to handle all the work.
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