Pronounced halos around high contrast edges using ICE

[JustRight]

Hi everyone,

Now that I have finally managed to get my copy of SilverFast Ai-Studio 6.2.4r9 calibrated using a Kodachrome IT8 target on my Nikon LS9000, I embarked on testing various settings for scanning my Kodachromes.

Unfortunately I immediately ran into a problem with SilverFast. When scanning at high resolutions in 48bit colour I found that SilverFast seems to have created strong halo's around the edges of objects with high contrast. These halos are visible when viewing the output TIFF file at 100%

For example, the first slide I tried out had a sign in the image with white lettering on a black background. SilverFast produced very noticable halos around the white letters.

I have tried various settings, and I am not using USM or GANE or any other SilverFast filter.

HOWEVER, and this is the killer, if I perform the same scan, at the same resolution and bit depth using Nikon Scan 4.02, I get a perfectly crisp image. Excellent focus, with or without ICE. No halos at all. Which I guess means that the problem is not in the scanner itself, but rather in SilverFast.

What could be wrong here? What is SilverFast doing in it's image processing that is making such a mess of these images?

I should mention that the halos are much larger than you might see on an oversharpened image, and I am not using any sharpening!

Could anyone offer any suggestions.

Best Regards,
Trevor White


PS: Purely as a matter of interest. The colour quality of the scans is almost identical. Which indicates to me that the 'Kodachrome' settings within Nikon Scan are actually pretty good, as the scanned image was virtually identical to the one produced by SilverFast via the ICC profile built from a genuine Kodachrome IT8 target.

[RAG]

Hello JustRight,

Take a look to see if SilverFast is using the same scanner profile that Nikon Scan 4.02 is using. This is just and idea because I found quality differences between Epson Scan and SilverFast until I matched scanner profiles.

[JustRight]

Hello again,

OK, it turns out that I was wrong in thinking the problem was not related to Digital ICE.

After some additional testing I have verified conclusively that the halos are only produced when the ICE option within SilverFast is enabled.

With ICE turned off the image is output sharp and clear, but with the usual dust mites etc. With ICE turned on the halos appear (although the dust mites are now gone).

When performing the exact same scans using Nikon Scan 4.02 this does NOT occur. The images are sharp and clear whether ICE, or ICE-Fine is turned on.

Why is the SilverFast implementation/processing of Digital ICE different from the way Nikon Scan works?

Checkout the images for a sample of what I mean.
Note that these images are crops of a small area of the actual image viewed at 100%

Nikon Scan with ICE-Fine
<img src="/img/forum/nikon_scan_with_icefine.jpg">

SilverFast without ICE
<img src="/img/forum/silverfast_with_no_ice.jpg">

SilverFast with ICE
<img src="/img/forum/silverfast_with_ice.jpg">

SilverFast with ICE-Fine
<img src="/img/forum/silverfast_with_icefine.jpg">


Can anyone offer any suggestions about what may be going on here?
SilverFast?

Best Regards,
Trevor White

[degrub]

This one looks like it needs a problem report submittal

[RAG]

Here is the link to the support form.

http://www.silverfast.com/problemreport ... opic=Usage

[JustRight]

This one looks like it needs a problem report submittal

Yes, I agree, and have now submitted a problem report. I hope that the Lasersoft guys have a simple solution for me.

I should add that the implementation of Digital ICE on the Nikon LS9000 works perfectly well on my Kodachromes. Using Nikon Scan I have absolutely no issues with Kodachrome and Digital ICE. Even using SilverFast the cleanup on the Kodachromes is excellent using Digital ICE, it's just these annoying halos that are a show stopper for me!

Cheers,
Trevor.

[degrub]

BTW, there is a new version out for the scanner.

[JustRight]

BTW, there is a new version out for the scanner.

So there is! 6.4.3r6

I will check tonight if this is available for the Nikon. The last time I checked for an update (which was not very long ago) only 6.4.2r9 was available for the LS9000.

Thanks for the heads up.

[JustRight]

Just a quick update.

The new 6.4.3r6 version exhibits exactly the same behaviour when ICE is enabled.

I wonder just what could be wrong?

[JustRight]

OK, I think I know what is going on.

The issue here is Digital ICE-4 which is implemented on the latest Nikon scanners like the LS9000. I believe that Kodak/Nikon call this Digital ICE-4 'Professional'.

The critical difference (apart from the inclusion of GEM and ROC etc) is that ICE-4 is Kodachrome friendly. Within Nikon Scan you select 'Kodachrome' as the film type, and this causes the scanner to use a lower power version of ICE, which is not as effective as ICE-3 in cleanup, but does a respectable job anyway, whilst preventing the problems of blooming and halos around high contrast objects. Apparently this problem with halos is common with Kodachrome and Digital ICE-3.

So when enabling ICE within SilverFast, there is no way that the software can tell the scanner that we want to use the 'Kodachrome' friendly version of ICE-4, and so we end up with halos and other side effects from using the full power version of ICE, effectively ICE-3. Ideally, SilverFast should allow us to specify 'Kodachrome' when enabling the ICE option button so as to make use of the superior capabilities of scanners like the Nikon LS9000 and it's implementation of ICE-4 Professional. Presumably the NikonMAID SDK supports this switching of the ICE 'mode', as Nikon Scan is clearly able to do it.

So I guess that means I won't be using SilverFast any time soon with my LS9000 and Kodachrome. I have to tell you that this is a HUGE disappointment because SilverFast is much better than Nikon Scan in many other areas.

Anyway, I will communicate with the LaserSoft support people with what I have found out and see how I go.

Best Regards,
Trevor White

[LSI_Magnussen]

Dear Trevor,

thank you very much for your hard work to inspect this problem.
We will contact Nikon and will hopefully be able to include this special ICE mode in one of the next releases.

Best regards
Ralf

[JustRight]

Hi Ralf,

Thankyou for the positive reply. I can only hope that this is a 'relatively' simple enhancement and that the Nikon SDK will in fact support this 'Kodachrome' mode for third party developers like yourselves.

I for one would look forward with great anticipation to this enhancement if it were possible. I'm sure that every other Nikon LS9000 owner that is scanning Kodachrome would be the same. With this addition, SilverFast Ai-Studio would simply have no competition in my opinion. This is particularly true for me now that I have been able to perform IT8 calibration using a genuine Kodachrome target. The results from SilverFast, forgetting about ICE for the moment, are excellent.

Just for interests sake, for any other users following this thread, I have posted a pair of images below just to prove the point about ICE-4 and the special Kodachrome mode. The first image is a crop taken from Nikon Scan in 'Kodachrome' mode with ICE enabled. The second is a crop taken from Nikon Scan in the standard 'Positive' transparency mode where ICE-4 is enabled at 'full' power. You can see that even Nikon Scan will produce the halos etc in this case!

Nikon Scan with 'Kodachrome' film setting and ICE enabled
<img src="/img/forum/nikon_scan_with_ice4_kodachrome_setting.jpg">

Nikon Scan with standard 'Positive' film setting and ICE enabled
<img src="/img/forum/nikon_scan_with_ice4_standard_transparency_setting.jpg">


So there we go. Kodachrome friendly Digital ICE. Will wonders never cease


Best wishes to all.
Trevor White