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Old Feb 16, 2011, 12:28 PM   #1
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Default Scanning Issues (reflective surface)

Hi all,

I have a bit of an issue with a unique situation, but hopefully there is a relatively easy solution. For several years I've been part of a group at the University of Alabama that does research on cave formations. We split a stalagmite in half, polish the surface flat then image it at high-resolution before taking samples of the material. Using a basic flat bed scanner (Epson 1660) typically works great as you can be assured the final image is: 1) high-resolution, 2) in perfect focus, and 3) is at a 1:1 scale in that when importing the image to photoshop/illustrator, 1 inch = 1 inch.

Unfortunately, with a few samples we have issues of the material being too reflective in that the final image is washed/blown out and there is no detail. Software will let you adjust your setting a little bit, but it seems I need to find a way to physically adjust things. Ideas I have thought of include using either ND filter sheets (although there seem to be 1000's to choose from) or maybe some type of polarized sheet? As far as I can tell, you cannot tell the scanner to reduce the intensity of its light source. In a general sense, if the rock is very clean it is very white and I cannot image it. In areas where there is dirt mixed in with the rock I do preserve some detail.

I have included 3 images below to demonstrate what I'm trying to describe with words. The first two images have issues, while the third one is what we're trying to get. The third one worked because it's a slightly different type of material that is not as reflective.

Maybe there is a better quality scanner that will let me have more control? If some type of sheet between the scanner bed and sample would work, where should I start experimenting? Whatever, I use can't be too thick or else the sample goes out of focus as it is father away from the glass.

Thanks in advance!

Joe

Example 1


Example 2


Example 3
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Old Feb 17, 2011, 12:49 PM   #2
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Default Scanning Issues (reflective surface)

Scanning Issues (reflective surface)
.
Hello:
- I do not claim to be an "Expert", of any kind, when it comes to scanning.
- I am only stating actual results that I have actually used and found.

================================================== ===

You are using the correct type of scanner. --> A true image scanner.

Your --> Epson 1660: (Specifications)
- Optical Resolution = 1600 by 3200 D.P.I.
- etc.
My --> Epson Perfection V500: (Specifications)
- Optical Resolution = 6400 x 9600 D.P.I.
- etc.
Optional --> HP Scanjet 8300 Professional Image: (Specifications)
- Optical Resolution = 4800 D.P.I.
- etc.

================================================== ===

Image Scanning: (D.P.I.)
- I would suggest that you use a much higher D.P.I. (Dots Per Inch), image scanner.
- Each higher level of D.P.I. (Dots Per Inch) you use, on an optical resolution image scanner,
will improve the image clarity by that much more.

Image Scanning: (Intensity of scanner light source)
- There is no way to "reduce" how bright the scanner light source, is.
Image Scanning: (Neutral Density Filters)
- I know nothing of this type of item.
- I do know, that astronomy requires special colored filters (Lens) to block out a certain colored ray.
- Using any type of "filter" will "alter" the "true / actual" colored image.

Image Scanning: (Software)
- An image scanner, only copies, and saves the image, using the present hardware.
- An image scanner, has no control over how shiny or dark, the object, to be scanned, is !
- Custom image software, may be required, to enhance the "true" image.
- Custom image software, will now only "enhance" the lighted and dark sections.
- You state that you are presently using photoshop / illustrator.
- I am presently using, Adobe Photoshop Elements 6.0

Your Images: (Downloads)
- Image 1 & 2.
- I downloaded two (x2) of your images.
- I ran the two (x2) of your images through , Adobe Photoshop Elements 6.0.
- I received two (x2) of your images, same as or better quality, at "half" the file size !

================================================== ===

Conclusion: (D.P.I.)
- The "higher" a scan D.P.I. (Dots Per Inch) is used to scan,
- The "better" a scanned image, can be enhanced,
- Using 'true" enhanced, digital software.
.
..
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Old Feb 19, 2011, 7:34 AM   #3
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Does your scanner allow you to scan in 48-bit color? If so, try using that mode, as the gradations will be finer and should allow more detail in the highlight areas.
I have heard good things about VueScan software, though I haven't used it myself. You might want to give it a try.

brian

edit: I took the liberty of running your second image through Martin Sykes' AutoHDR software, and found it recovered quite a bit of the highlight details.
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Last edited by VTphotog; Feb 19, 2011 at 7:44 AM.
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Old Feb 20, 2011, 3:32 PM   #4
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Default Scanning Issues (reflective surface)

Quote:
Originally Posted by VTphotog View Post
brian
edit: I took the liberty of running your second image through Martin Sykes' AutoHDR software,
and found it recovered quite a bit of the highlight details.


Brian:

This digital software (Martin Sykes' AutoHDR) sure did a great improvement.
It looks a lot better, over my copy and testing, using Adobe Photoshop Elements 6.0

Just image, how much more detail could be digitally saved, if the University of Alabama,
converted from their old --> Epson 1660: (1600 by 3200 D.P.I.),
to a much newer --> Epson Perfection V500: (6400 x 9600 D.P.I.).
Over (x3) D.P.I., being scanned !
.
..
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Old Feb 20, 2011, 6:51 PM   #5
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The problem here isn't due as much to the resolution of the scanner in DPI, as it is the exposure setting.
I am not familiar with the Epson scanner control software, but others I have used are able to control the exposure. Since the light and aperture are fixed in a scanner, the exposure time is used to adjust the overall lightness of the image. The VueScan software can be used for this if the Epson software isn't able.

brian
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Old Feb 25, 2011, 2:26 PM   #6
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Brian and Old Boy,

Thanks for your tips! We're making some progress with this. I've downloaded both the free AutoHDR software and the full demo for the VueScan. Regardless of scanning DPI with old vs. new scanners, we're probably going to look into a new scanner for several reasons.

Brian,

1) Do you recall which scanners you've worked with in the past did give you control over the exposure settings? The Epson 1660 only has Autoexposure settings. Even with the VueScan software (v. 9.0.20), it seems the "Exposure" button under the "Scanner" tab also does some type of auto-exposure correction. Maybe I'm missing an advanced settings control somewhere. It would be great to be able to have full manual control over the exposure.

2) You were able to pull out more detail with the AutoHDR software than I was able to get with Photoshop CS1. Do you happen to remember which values you tweaked the most, contrast, etc.?

By the way, the Epson 1660 does do 48bit color. I'm currently looking at the Epson Perfection V700 and the Canon CanoScan 9000F.

Thanks again!

Joe
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Old Feb 25, 2011, 6:15 PM   #7
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The Microtek scanner I use, and the scanwizard software, allows full exposure control, but that is all I am really familiar with. I do believe that in order to access it, one has to use the advanced settings, though.
IIRC, the autoHDR settings I used were the default settings except for the highlights, which I increased to 8 or 9.
I haven't used the Vuescan software myself, being pretty well satisfied with the Microtek for my purposes.

brian
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Old Mar 1, 2011, 1:23 PM   #8
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Default Scanning Issues (reflective surface)

With my Epson Perfection V500, I tried different features.
I was unable to configure the scanner hardware, for light control.

- BUT -

After I copied 1,500 35mm slides, I did find that the clearer the original scanned image was,
the better, the enhanced software, worked !

My Conclusion:

The clarity an original image scanned,
will determine how well an enhanced software program, can / will work.
For image transfer, dots per inch, (DPI), should be a major controlling factor.

You can only get out, what you put in !
(Garbage In = Garbage Out).

.
..
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Old Mar 14, 2011, 11:20 AM   #9
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I know this may be an "old school" method, but have you considered going with a copy stand arrangement. Polarize your light source, polarize your lens and you will not have any problems with reflection. A good image sensor and sharp lens on the camera will get you the clean images you want, without having to wait for the scanner.

Put a sheet of foam on the copy stage then place your sample on the foam. This will help keep the slice surface parallel to the image sensor.
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