Loss of Shadow Detail in Green Channel

[BillMcMannis]

I am scanning some 4x5 transparencies that show shadow detail when I view them on a light table. When I scan them in SilverFast Ai Studio v6.5.0r4a I loose most of this shadow detail. If I look at each channel in PS, red and blue show the detail, but it is lost (big black detailess blobs) in the green channel. If I adjust my level to compensate this, my shadows either take on a greenish caste or a speckled green caste. I usually scan in 48bit, with the 4 pass ME.

Any suggestions would be appreciated.

Thanks!
Bill

[LSI_Heidorn]

Dear Bill,

could you try out to scan a 48 Bit HDR Color Scan and to analyze that image ?

If the green channel is also sgowing that behaviour on a HDR Scan, then the Hardware really doesn't deliver ( may doublecheck with the EPSON driver to be 100% sure ).

If there you find the "lost" details in that HDR Scan, then there is hope that your input profile and/or settings are unsuitable ( i recall your other post about settings going bad... )

Greetings,

Nils Heidorn, R & D, LaserSoft Imaging AG

[BillMcMannis]

I tried 48bit HDR; the results are far worse than a standard 48bit 2 or 4 pass ME. The HDR scan comes out very VERY dark. If you attempt to adjust levels you get the nasty green problems that prompted my initial post.

Thanks!
Bill

[LSI_Heidorn]

Dear Bill,
the images beeing dark is quite normal, as the raw signal from the scanner *is* that way...

If adjusting the levels lead to the same kind of image, only worse "blobs" in the green compared to MultiExposure or MultiSampling then the Hardware is simply not able to resolve that shadow detail.
( Exactly this kind of problem was the cause for our Multi-Sampling and now for our Multi-Exposure, to stretch the dynamic range beyond its designed capabilities ).

I'm sorry, but you might have to upgrade your scanner hardware, what scanner are you using btw. ?

Greetings:

Nils Heidorn, R & D, LaserSoft Imaging AG

[BillMcMannis]

I am using an Epson 4870.

Thanks!
Bill

[LSI_Heidorn]

Dear Bill,

the 4870 is a decent Flatbed Scanner, i wonder about the density of your film material...

However there is a reason that dedicated FilmScanners and $100.000 Drum Scanners exists, and maybe that film of yours is the reason why...

To give it a last check if everything is set up well, did you try to scan it in the Original EPSON Software ?
Outgoing from your scan wit HDR, normally EPSON Scan Software should not come up with a better result, may give it a try.
IF the original Software delivers better details in the shadow area, then there definately is something wrong, but as stated above, i think your Scanner is simply out of its depths, even out of the depths that Multi-Exposure can reach on your Hardware...


Greetings:

Nils Heidorn, R & D, LaserSoft Imaging AG

[BillMcMannis]

Hi,

My scans using Silverfast 48bit 4xME are the closest to being acceptable. Going with the bare bones Epson scanning software yields results that are inferior to the 48bit 4xME, but these are superior to the SilverFast HDR's.

What do you think I am doing wrong?

Thanks!
Bill

[LSI_Heidorn]

Dear Bill,
it could be how you handle / process the scans after scanning with HDR...
How about the Quality if you use exactly the settings of the MEX-4 Scan just with MEX disabled ?!
Those should be pretty close to the result of EPSON Scan if not better.

Please take note that many Scanner manufacturers also blur the extreme shadows to mask the noise problems of their Hardware without saying so, could this be why the EPSON Scan looks better than the HDR Scan ?!

Greetings:

Nils Heidorn, R & D, LaserSoft Imaging AG

[BillMcMannis]

Hi Nils,

My results remain inferior, but perhaps I am doing something wrong.

Do you mean MEX does not work with HDR?

Thanks!
Bill

[LSI_Heidorn]

My results remain inferior, but perhaps I am doing something wrong.

Dear Bill,
what do you mean exactly -> postprocessed HDR Scans beeing inferior to 48 Bit Color MEX Scans or inferior to EPSON Scan results or both ?!

Do you mean MEX does not work with HDR?

MEX works fine with HDR, its just that HDR images look awfully dark when you open them at first in HDR-Scan unaware applications such as Photoshop or the like !

The HDR Scan with MEX enabled contains the same Quality of Data as the 48-Bit Color Scan with MEX.

I still fear that your Hardware maybe is not sufficient to get everything out of your image even if MEX stretches the limit...

Greetings:

Nils Heidorn, R & D, LaserSoft Imaging AG

[BillMcMannis]

Hi Nils,

I really think my hardware is capable of of creating the scans I need. As the detail I need is visible when I place the transparency on the light box it would seem that if my aging naked eyes can pick up detail, so can my Epson 4870.

Scanning at 48bit 4MEX I get okay results. Scanning HDR is as you say much darker. But what can I do with these darker images? Manipulating them in Photoshop does nothing to give me an image that is usable. When I scan in HDR, it embeds my scanner's transparency profile. Is this normal?

Thanks for the advise, Bill