Descreen Moans, Groans and Algorithm Pains

[dougc]

Ok, I know the descreen feature has beed debated elsewhere but can I run this past anyone interested...

I'm a designer working on book which is essentially a reprint of old magazine articles. I recommended to my client they buy a Microtek i900 for the task. Spec seemed good and it came with Silverfast Ai. Had a look round this site and was impressed with the auto-descreen demo (as you are with demos) and since this is a key part of the job in question it seemed a major bonus.

First gripe, SF site says of the descreen feature:

* Ai, DCPro and HDR offer the complete descreening dialogue with preview, manual selection and automatic screen-detection. The fully automatic functions are not included.

Great methinks. Auto de-secreen detection, and therefore removal, here I come. I visit my client to set up new scanner and soon discover that, er, the SF Ai that ships with it doesn't have the auto-detect feature. I now expect to get swiftly pointed to the bit of the software agreement that explained this and yes, I can now see the demo is Ai Studio, but come on SF I think the site page on descreening quoted above is somewhat misleading.

Anyhow, I still have a job to do - and assuming the MD of SF is not about to offer me a free Studio upgrade - is the auto-detect worth the extra 60 bucks? Anyone used it and find it great?

I have to say I've found the SF descreen no better - in fact slightly worse on first tests - than Microtek's own Scanwizard software. Furthermore I do need to up the resolution of some of my scans and the lpi input ratio thing on SF is limiting. (No need for anyone to post up explanation of screen algorithms and the optimum scan resolutions of already printed matter. I've read the other very useful posts, tried the tricks kindly suggested and understand the logic - but with text and graphics as well as printed images you just sometimes need a bit more res to play with than what's in the original printed matter).

I like the look of the auto-detect descreen but if the Ai Studio version also prevents lpi enlargement above 100% without canny reworking of the input ratios, and, it doesn't improve on the descreen of the MT scanwizard it looks like I've backed the wrong software for this job.

[RAG]

dougc,

I think the best thing would be for you to download the Demo version of AI Studio and give it a try.

It is possible to exceed %100 (up-sample) scans. You just need to watch out for interpolation caused by exceeding the scanners optical resolution.

I hope this helps!

Best of luck!

[dougc]

Sorry if this is a stupid question but I can only find a demo of AI on the site - not AI Studio. Could you point to me wher the AI Studio demo might be please?

[RAG]

The demo should be downloadable at the following link:
http://www.silverfast.com/show/silverfa ... io/en.html
Look for the following link on this page.
<img src="/img/forum/ai_demo.gif" alt=Silverfast AI Studio GIF width="258" height="56" />

[LSI_Marquardt]

Dear customers,

at first, I beg your pardon if the showcase might have misleaded you.
The full automatic descreening is within the Ai Studio only.
The Ai has a half automatic.
Since August 2005 the new descreening allows higher input dpi values
(although I recommend 600dpi as best input res.) and scaling to exact pixel values is possible either.
Regarding quality I can't follow you with ScanWizard beeing better in any matter. With SilverFast you get least artifacts, maximum sharpness - if you compare it carefully to other software. Although it is a matter of settings - if you like more sharpness but don't mind artifacts you can adjust the screen values to your favour. If you are not convinced - please send me example images (+ the undescreened sample) for analysis and please tell, what's in your opinion better or worse.

P.S. The Ai demo versions are Studio versions in demo mode.

Kinde regards,

Philipp Marquardt
LSI Development