Hi bit gray with Howtek 4500

flatbed scanners for Howtek

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Joined: Sat Oct 05, 2002 7:42 pm

Hi bit gray with Howtek 4500

Postby Tyler » Sat Oct 05, 2002 7:46 pm

In working with hi bit grayscale scans of B&W negs with Silverfast and a Howtek 4500, I've run into some problems. In Photoshop, moderate curve edits seemed to give me gaps in the histogram unexpected with 16 bit files.
I went back and tried every conceivable way of scanning provided by the software, then looked at the histos in Photoshop, looked at the "unique colors" in each as revealed by Bruce Lindbloom's Levels app.
I included a step wedge in each scan so I could also edit each to the same approximate tonality to see how robust each method was to editing.
The results are very disappointing. It seems the Silverfast/4500 combination returns a number of bits or tones far fewer than other much less expensive scanners I have used, and the files don't stand up to much tonal editing compared my past experience.
Silverfast has an "HDR" mode, that supposedly saves raw high bit scans. Even these are disappointing. There is a gamma setting in Silverfasts prefs, and an option to apply it to HDR mode or not. When applied, it's amazingly destructive, throwing out approximately 3/4 of the levels, according to Bruce's app. However, even with no gamma applied by Silverfast, the "raw" files are not impressive.
Other methods of editing within Silverfast before the file comes up in Photoshop, while obviously delivering a visually closer image, are also less than impressive in terms of level and robustness.
Is this real life, or is Silverfast not giving me access to the 4500's capabilities?
Any comments would be most helpful.
Thank you

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SilverFast Professional
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Joined: Tue Apr 09, 2002 1:00 am

Postby LSI_Kratzenstein » Wed Oct 09, 2002 2:41 pm

Hello Tyler

SilverFast supports 16bit scanning first with version 5.5.2 . Before you could only scan 8bit or 16bit raw data. HDR scan is primary to use the raw picture in SilverFast HDR, so the scan could be done in the night, and with HDR you could "scan" the raw data very quick, so you don't need to wait a long time after make the settings.
What SilverFast you use currently ? You could try our demo of version 6, if you like to.

kind regard,

Kristian Kratzenstein

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