Descreening great...... but sloooooooooooooooow

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MicroSF6
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Descreening great...... but sloooooooooooooooow

Postby MicroSF6 » Sat Dec 10, 2005 12:51 am

So I am the first to admit that the latest incarnation of Silverfast (Microtek 9800xl using SF6 plugin 6.4.2r9) has the ability to descreen unlike any previous versions I was aware of.

BUT.... does it have to take so long? I think scanning now takes double the time, if not more. Is there not an option of use the old algorithms rather than reloading an older version of silverfast.

Even normal scanning now takes an age I find. I just don't understand why it must take so long. Almost tempted to go back to Scanwizard just because there is barely enough time in the day even if I run the scanner continually.

Any ideas out there? Or are there glitchs with certain systems? Does Silverfast have a benchmark for what an A3 at 48bit 600dpi 50% should take? At least then I'd know if what I am getting is normal.

Thanks,

Kenneth Beck

degrub
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Postby degrub » Sat Dec 10, 2005 3:42 pm

Not knowing anything about your system:
Adding memory can often help this type of issue
The descreening algorithm may be a n2 process where the compute time goes up as the square of the number of elements. That gets ugly real fast.

regards,

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RAG
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Postby RAG » Sun Dec 11, 2005 12:52 am

The descreening algorithm is processor intensive! When it runs on my system I can hear a substantial noise increase as the processor fan kicks into high gear.

If you don't like the feature you could always take the time to descreen after the fact with a photo editor if you think that would work faster.
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Helpful Corn
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Postby Helpful Corn » Fri Dec 23, 2005 5:06 am

I must say that I'm not very happy with this latest version of Silverfast either. Descreening is unacceptably slow; in fact, it starts, then completely hangs after about five minutes on my system. (It does not matter if I use the Silverfast launcher or the Photoshop plugin). Normal reflective scans without descreening are fast, but the image quality is much worse than the results I was getting with the previous version of Silverfast. Nothing about my system has changed, so I find these results to be disappointing, to say the least.

Time to roll back, I guess.

My system:

Windows XP Pro
1 GB RAM
Photoshop CS2

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RAG
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Postby RAG » Fri Dec 23, 2005 8:11 am

The quality of my scans has not been degraded at all. With the previous version I would get solid gray output when ever I attempted to use either of the automatic de-screening features. The scan times did not increase, but it took and takes a bit for the de-screening algorithm to complete, but the results I have gotten with this version have been phenomenal!
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LSI_Marquardt
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Microtek&Descreening

Postby LSI_Marquardt » Thu Feb 23, 2006 9:18 am

Dear Customers,

there were several issues with Microtek Scanners in the past,
which did force us to increase scan resolution internally to avoid some
"line drop out" effects. This issue does not occour any longer with most recent Microtek drivers and the workaround we took will be took back in a next release! Therefore scan time will be as fast as in ScanWizard.
The descreening uses, due to quality reasons at least 600 dpi to be 100% aware of moir?. That is why it needs longer than expected. In an earlier release the next native scan resolution was taken - at Microtek this was 800,
but we changed this due to speed issues and now do a interpolation to 600 dpi for descreening as well. In a most recent version the descreen might be faster for you.
Nevertheless we think about a draft mode with a little bit lower quality for the future.

Best regards,
Philipp Marquardt
LSI Development

c5nest
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Postby c5nest » Sun Mar 19, 2006 2:56 am

The slow descreening in the new version of Silverfast makes it absolutely unusable on my system. A scans that previously took 90 secs now takes approximately 10-15 minutes!

This is really not good...guess I'll go back to the previous version until this is fixed.

XP Pro Dual Xeon 2.3 Mhz/2.5 GB RAM & Epson 4870

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RAG
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Postby RAG » Sun Mar 19, 2006 11:10 pm

OK,

I thought I would run another test to see how de-screening would work for me with version 6.4.3r9 and I was very surprised to find that at the end of the process Photoshop closed down with an error Vs the de-screened image being displayed.

I restarted my computer and gave it another try with the same results, and yes I cleared my Prefs as well. Just for giggles I tried the manual de-screening and that worked. I went back and tried automatic de-screening afterwards and that seemed to work as well.

In summary will work, just not consistently. :-(
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