SDR doesn't work with SS120 for 645 scans at 4000dpi

[Doug Nielsen]

I submitted the following to Lasersoft this morning. I would be interested if anyone else has experienced this problem. I will post Lasersoft?s answer when I get it.

"SDR, when it works, works quite elegantly. However, I am unable to make it work for the scans I wish to perform.

I am running SF6.0.1r18 with Photoshop 7.01 using a Polaroid SS120 Scanner and a Macintosh G3/ MAC OS9.1.

The problem I have encountered is that I am unable to produce SDR Preview and Navigation Window images under some combinations of image dimensions, resolution and file size. I get proper operation for 35mm (or 645 negatives cropped to 0.9 by1.3 inches) at 4000dpi. This works whether I scan at 8 bit Gray Scale or 48 bit RGB. However, for full (100%) frame 645 image dimensions, the maximum usable resolution goes down to about 2100 dpi. Again it doesn?t seem to be effected by the bit-depth (file size) or image type I select. 645 scans cropped to intermediate sizes can be successfully SDRd at intermediate resolutions (ie greater than 2100dpi but less than 4000 dpi.

When I scan at an image size/resolution/file size that wont SDR properly the view shown in the SDR Navigation window appears as a horizontally-torn unrecognizable image. The Preview window will show repeating misplaced, improperly framed, and sometimes distorted sections of the scanned image.

SF version SFE-6.0.1r07 (Polaroid) produced the same results.

My interpretation is that that problem is some type of programming bug and is not a true program limitation.

I would certainly appreciate some help."

Doug Nielsen

[LSI_Belli]

Dear Doug,

could you please send your Prefs directory to support@silverfast.de when the problem appears, so that we can analyze the problem ?

And to be sure that the problem was well understood:
- you scanned 645 images (without restarting SilverFast in between?)
- SRD seems to have some problems when the resolution is greater than 2100 dpi (scale at 100%). And how about with a scaling factor of 110-120%?

Thanks for your cooperation.

Regards.

Thomas

[Doug Nielsen]

Thomas

Previously I overlooked the possibility that restarting SF between attempts to apply SDR would have an effect, and my earlier observations were made without restarting between attempts. However, almost all of my previous attempts were done with SF set to 645 scans and I examined smaller formats by merely changing the cropping.

I had previously looked at scanning at a lower resolution (2000dpi) and increasing the scale (200%). The problem still existed with that setting. I repeated that approach this morning restarting SF between each attempt and still met with failure.

As you suggested I have emailed copies of the Prefs Directory (Folder to us Mac Heads). I have included two sets. The first set was copied immediately following a failed SDR attempt at 2600 dpi and the second was copied following a successful try at 2000 dpi.

I am anxiously awaiting a solution. Thanks for your help.

Doug Nielsen

[Doug Nielsen]

I need to add some information that may more specifically define the problem.

As Thomas implied I should do, I did a series of scans of a 645 negative at various dpi?s restarting SF in between tries. I found that I actually had to restart Photoshop not just SF to have any effect. Further, restarting PS between SDR applications did not solve the problem, but I did get different results than before -- ie, the resolution at which SDR would not work was at a different value. Additional messing around showed another interesting effect. If I ended an attempt at applying SDR by clicking the Cancel Button, the subsequent attempt would always fail regardless of the resolution set (unless I restarted Photoshop). However, if I ended an attempt by clicking the OK Button the result of the following attempt was independent of the result of the previous attempt. That seems to be true whether I restart Silverfast or Photoshop or not.

While I was still restarting PS between SDR applications I thought I had pinned down a possible clue to the problem. Without changing the framing/cropping setting I found I got successful SDR results when the image width was set at 4095 pixels and that SDR failed at 4097 pixels. This was satisfying in that 4096 is 2^12. I jumped to the conclusion that the problem was image widths greater than 2^12th. That theory went down in flames when I changed the cropping set and then later tried to recreate the earlier placement. Even when I reset the cropping to give the same values I had recorded earlier for both width and height, the success/failure boundary now was at an image width of 4112/4113 pixels. Close but not at the magic value of 2^12th.

In summary, I have learned some things, but I still can?t use SDR at the image size and Resolution that I need - full 645 frame at 4000dpi.

I presume that no response means that you were able to use the Perf files I sent you earlier at support@silverfast.de . If not let me know and I will send additional files using a compression scheme you specify.

Thanks for your help.

Doug Nielsen

[LSI_Belli]

Dear Doug,

our developers team is analyzing the problem.

Regards.

Thomas

[Doug Nielsen]

It?s not clear whether anyone else encountered the problem I reported in my 30 September submission. In any event, I am happy to report the problem appears to have been satisfactorily resolved with the r25 SF 6.01 update.

I can now use all of the functions of SF6 with a Polaroid SS120 even for 4000dpi scans of 645 format negatives.

My thanks to Thomas Belli and the Lasersoft staff for their efforts.

Doug Nielsen