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Author Topic: Scanning photos in high bit rates  (Read 1769 times)
Jonathan Wienke
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« on: May 19, 2005, 02:22:35 PM »
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And the correct answer is...

None of the above. If your scanner can actually scan in 48-bit mode than it will indeed output in 48-bit mode if you select an output file format that supports >8 bits per channel, like TIFF. JPEG is 8-bit per channel only, and in any event is totally unsuitable for images you will be editing extensively. Better yet, scan directly into Photoshop in 48-bit mode. If this is not possible, then get rid of your scanner and replace it with one that has a 16-bit per channel (48-bit total) output option.
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Jonathan Wienke
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« Reply #1 on: May 20, 2005, 03:51:53 AM »
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It's me again...

The scanner is a HP ScanJet 2400, and wherever I look on the Net, it is said to support 48 bit color mode.
But however I try, even with it's own scanner software, the bitdepth selections are limited to: Millions of colors, 256 color, 256 gray shades, 1 bit BW.
I know JPEG's limitations, I scan to TIFF (or compressed TIFF).
The output image will be 24 bit only.

So, the trick I want to use is essential for me, because I have no money now for a new scanner. But you are all can feel free to send me one if you don't need it anymore
Initiate the scan from Photoshop, and there is a check box hidden in the driver settings to enable 16 or 48-bit output for clients that support it. Your mission, should you accept it is to find that check box and enable it. Make sure you have tha latest drivers installed also.
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Jeno1
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« Reply #2 on: May 19, 2005, 08:45:12 AM »
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Hi!

My problem is:
I have a BW pic on paper that I'd like to process in 48 bit.

My scanner can scan pictures in 48bits per pixel, but the output image bitdepth is limited to 24bpp.
The scanner's software allows me to set basic levels and gamma, so I think it is possible to cheat "a bit" and scan the image in multiple steps with different settings, so each scanning step captures only a portion of the full detail.

For example at step 1/3 I scan the details of shadows, at step 2 I scan the middle channels and finally in step 3 I capture the details of the highlights. Each step would end up in a 24bpp image, and finally in Photoshop I could build up a 48 bit image, that, if contains not even true 16 bits per color, surely way more than 8.

I've made several tries, but what I get is something that doesn't really meet the original picture.

I can set in the scanner's software the highlisghts' limit, shadows' limit, each 0-255, gamma (1.0-4.0) and black and white level, each from 0 to 255.

My main question is: Is there a mathematical formula, that gives an exact solution of these settings based on the parameter of the number of scanning steps?

And my second one would be:
How can I blend these images to build up the "original" picture?

I think the steps would be something like:
1. convert from 8 to 16 bpc
2. adjust contrast to shrink the histogram to the boundaries that represents the actual information corresponding to the final image.
3. use some sort of blending method to build the final image that stores values of each pixel in more than 8 bits per color.

Mathematicans, professional photographers and PhotoShop users, helpme now!

PS: Sorry for my english, I hope you get me, I've tried to describe my problem as clean as I could. If you don't understand something, ask for details

Thanks in advance!

J. Borsodi
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Jeno1
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« Reply #3 on: May 20, 2005, 01:29:23 AM »
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It's me again...

The scanner is a HP ScanJet 2400, and wherever I look on the Net, it is said to support 48 bit color mode.
But however I try, even with it's own scanner software, the bitdepth selections are limited to: Millions of colors, 256 color, 256 gray shades, 1 bit BW.
I know JPEG's limitations, I scan to TIFF (or compressed TIFF).
The output image will be 24 bit only.

So, the trick I want to use is essential for me, because I have no money now for a new scanner. But you are all can feel free to send me one if you don't need it anymore
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Jeno1
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« Reply #4 on: May 20, 2005, 06:31:00 AM »
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I've get news!

I've found some interesting stuff in the driver directory.

I found this line in 2400.ini:

bScanAtMaxPixelDepth=0

I assumed the first letter "b" stands for "boolean", so I set it to 1.
Voila! I thought it would be much harder than this!

Thanks for the advice!
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