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8/16 bit images! What's the difference !

View Poll Results: In reading the article on 8/16 bit images. Can you tell the difference?
Can not tell the difference. 7 28.00%
Can tell the difference and let me explain. 9 36.00%
16 bit images is just a waste of space(longer processing). 3 12.00%
I would like to remain neutral on this subject. 6 24.00%
Voters: 25. You may not vote on this poll

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  #1  
Old 10-01-2002, 07:54 PM
john_opitz john_opitz is offline
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8/16 bit images! What's the difference !

http://www.ledet.com/margulis/PP7_Ch15_Resolution.pdf

The 8/16 bit article starts on page 310 of this pdf. file.
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  #2  
Old 10-01-2002, 09:35 PM
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Ed_L Ed_L is offline
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Good question John. Maybe I'm getting older, and can't see the difference. But I've read a lot of text supporting the 16 bit per channel option, and I've tried several scans at 8 bit, and 16 bit without being able to see a difference. So to my mind, unless there's a strong case for using 16 bits (a lack of tonal structure), I see it as a waste of space, and a loss of Photoshop features. So far, I haven't found an image where I could see the difference.

Ed
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Old 10-01-2002, 10:21 PM
john_opitz john_opitz is offline
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I have to agree with you Ed. On the dcs 760 camera I use. I see no difference in 8 or 16 bit, except....the 16 bit is a little bit softer(louping the print). So I could go either way. Its the editing(in P.S.). As you stated. That's the problem. Their are ways of editng 16 bit in 8 bit mode(selecting and pasting) but it's a pain in the neck. Too time consuming and nothing to gain from it. So I'm not a 16 bit die hard.
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Old 10-02-2002, 03:35 PM
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Trimoon Trimoon is offline
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As a printer I can see the difference. Hear is how Adobe explains it
Bit depth--also called pixel depth or color depth--measures how much color information is available to display or print each pixel in an image (more bits of information per pixel) means more available colors and more accurate color representation in the digital image.
A pixel with a bit depth of 1 has two possible values white and black.
A pixel with a bit depth of 8 has 28, or 256, possible values.
A pixel with a bit depth of 24 has 224, or roughly 16 million, possible values.
Common values for bit depth range from 1 to 64 bits per pixel.
In most cases, Lab, RGB, grayscale, and CMYK images contain 8 bits of data per color channel. This translates to a 24-bit Lab bit depth (8 bits x 3 channels); a 24-bit RGB bit depth (8 bits x 3 channels); an 8-bit grayscale bit depth (8 bits x 1 channel); and a 32-bit CMYK bit depth (8 bits x 4 channels). Photoshop can also read and import Lab, RGB, CMYK, and grayscale images that contain 16 bits of data per color channel.
I reproduce art for the artist and I need all the info I can get.

Last edited by Trimoon; 10-02-2002 at 03:55 PM.
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  #5  
Old 10-02-2002, 04:45 PM
shag-man shag-man is offline
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I can't find the difference. The other thing. If Adobe says that 16 bits is better, then why doesn't PhotoShop support adjustment layers,filters,ect..ect.. for 16 bits.
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Old 10-02-2002, 06:08 PM
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One reason is most system can’t handle the file size
“A 16-bit-per-channel image provides finer distinctions in color, but it can have twice the file size of an 8-bit-per-channel image”
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  #7  
Old 10-02-2002, 11:03 PM
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Tim_S Tim_S is offline
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A warning about Dan Margulis

Since I consider myself, at least well read on this subject, if not actualy knowlegable about it, I'd like to point something pertinent.
Dan Margulis in not unbiased about the 8-bit vs 16-bit debate.

Take a look at Bruce Lindbloom's site, go to imaging and look for the 16-bit challange article... it is an interesting read.

--tks
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  #8  
Old 10-03-2002, 03:52 AM
Stephen M Stephen M is offline
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You have to have a lot of fortitude to catch up with this whole debate, if you were not 'lucky' enough to be there and to follow the natural progression, as I have over time.

I would suggest reading the ACT archives for the first hand info as it unfolded (membership reqd):

http://groups.yahoo.com/group/colortheory

Or perhaps these two summaries:

http://www.ledet.com/margulis/ACT_po...bit-16-bit.htm

http://www.ledet.com/margulis/ACT_po...6-bit-2002.htm

These links in addition to the previous posts link should bring everyone up to speed on Dans latest offering:

http://www.ledet.com/margulis/PP7_Ch15_Resolution.pdf

Save this for when you have a LOT of spare time, then do your own tests as I have (I think each user should come to their own conclusion for their own setup and workflow based on their own tests).

Stephen Marsh.
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  #9  
Old 12-24-2004, 06:04 AM
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Doug Nelson Doug Nelson is offline
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Get with it, the new debate is 16/32

http://www.idruna.com/photogenicshdr.html
http://www.cybergrain.com/tech/hdr/
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  #10  
Old 12-24-2004, 11:10 AM
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Ed_L Ed_L is offline
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Very interesting to say the least! Thanks for the link.

Ed
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