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Old May 20, 2013, 12:16 PM   #1
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Default 8 Bit VS 16 Bit Processing

We always seem to be concern about getting the best image quality from each picture we shoot. Have read some good threads on how to take a shot, use the best lens, best camera, use a good tripod, lighting gear and even threads about which program to use for processing ones' shot. The one thing I haven't seen talked about or compared is a 8 bit vs 16 bit process file. Is there are difference between 8 to 16 bit files in image quality. If there is a difference between the two is it something that one can see in a 11x14 inch print? I ask because most PP programs and add on programs only do 8 bit, so what is the advantage if any to using 16 bit files over 8 bit files?

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Craig
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Old May 20, 2013, 12:42 PM   #2
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This is a good article that can explain better than I can...

http://laurashoe.com/2011/08/09/8-ve...t-really-mean/

Hope that's helpful...
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Old May 20, 2013, 12:56 PM   #3
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Good read, explains the theory very well, still wonder what real world side by side comparisons would look like on a printed photo.
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Old May 20, 2013, 1:06 PM   #4
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Quote:
Originally Posted by Calicajun View Post
Good read, explains the theory very well, still wonder what real world side by side comparisons would look like on a printed photo.
It mostly matters in post processing... If you shoot in lower bit depth and
need to work an image hard to recover shadows, etc, then the final image
could end up very choppy (posterized)...
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Old May 20, 2013, 2:27 PM   #5
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  1. JPEG files only contain 8 bit color. Most monitors and all televisions only display 8 bit color. Any printer can print 8, 10, 12, or 14 bit color. (I don't know of any cameras that can produce 16 bit color images, but if there are some, the chances are that printers can print them too.)

    If you open a 14 bit color image in your image editor, but your monitor can only display 8 bit color, you will have no idea what colors you'll get until you print.

    If you want to preserve the greater color information, don't use JPEG. Save your intermediate images in TIF, PSD, or the like.
    .
  2. The human eye can only detect about 10 million distinct colors. 8 bit color can render 16.8 million distinct colors. Unfortunately, not all the 10 million colors that we can perceive are within the 16.8 million colors that are part of the 8 bit color gamut. Going from an 8 bit color gamut to a 10 bit color gamut means that an image can include a few more of the individual colors that we can see, going from 10 bit to 12 bit means we can see a few more, and so on.
    .
  3. Even when using a very large color gamut in a RAW image file, not every photoreceptor detects every color of light. Whatever color advantage you get by using a larger color gamut will largely be lost when the values for green are shared with the four adjacent pixels, and the values for red and blue are shared with the eight adjacent pixels.


So, despite the hype, the difference isn't much, even if it can be detected.
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Old May 20, 2013, 2:31 PM   #6
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Even when using a very large color gamut in a RAW image file, not every photoreceptor detects every color of light.
That is, unless you're using a camera with a Foveon image sensor.
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Old May 20, 2013, 3:06 PM   #7
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TCav, nice read. I shoot in RAW only but have been exporting from LR4 in Jpeg format, think I'll give TIFF or PSD format a go and see what happens.

Thanks all,
Craig
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Old May 21, 2013, 9:24 AM   #8
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While JPEG, and even TIF and PSD image files contain red, green and blue color values for each pixel, RAW files only contain a single luminance value for each pixel. These luminance values are mapped to the color values for each of red, green, and blue, depending on the color of the portion of the Bayer filter over the particular photoreceptor. In order to display an RGB image (and to save an RGB image in a file format other than RAW), the RAW conversion process uses the luminance values of adjacent photoreceptors to get values for colors a particular photoreceptor didn't detect itself.

So the RAW conversion, in effect, waters down much of the advantage you might gain by using a greater color depth.
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Old May 21, 2013, 3:08 PM   #9
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Medium format backs like the Phase One IQ1 series output 16bit (48bit image) files
http://www.luminous-landscape.com/re...sor-plus.shtml

Quote:
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  1. JPEG files only contain 8 bit color. Most monitors and all televisions only display 8 bit color. Any printer can print 8, 10, 12, or 14 bit color. (I don't know of any cameras that can produce 16 bit color images, but if there are some, the chances are that printers can print them too.)
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Old May 21, 2013, 3:46 PM   #10
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Thanks.
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