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07/31/2007 08:57:18 PM · #1 |
| Just got Photoshop CS2 and was wondering how much better is 16bit mode than 8bit. Or I am really wondering whats the diffrence?? |
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07/31/2007 09:01:12 PM · #2 |
I asked this question a few months ago and got this response from kirbic;
Originally posted by kirbic:
For the best possible final quality, only convert to 8-bit at the end. That said, if you make your major tonal adjustments in 16-bit, that is the most important thing. Specifically, if you're adjusting contrast through curves or levels, or significantly adjusting exposure, it should be done in 16-bit. Dodge & burn are also best done in 16-bit. Things like cloning, sharpening, etc., are not that sensitive to the bit depth. It's mainly where you're changing the slope of the curve (contrast) or pushing values up or down significantly that 16-bit has the advantage. Doing these steps in 16-bit will produce smoother tonal transitions, greatly minimize posterization. The differences most often are subtle, but can bee dramatic at times. |
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07/31/2007 09:02:02 PM · #3 |
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07/31/2007 09:02:30 PM · #4 |
| Hee hee, I was gonna reply, and found I already had! :-) |
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07/31/2007 09:05:53 PM · #5 |
Sorry to steal your thunder kirbic!
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07/31/2007 09:06:47 PM · #6 |
Basically, the difference is that 16-bit is "smoother"; the gradations are more subtle, sort of. It's like if you had a 16-bit paint-by-numbers kit and an 8-bit version, the 8-bit version would have would have a lot fewer colors than than the 16-bit version. From a distance you wouldn't be able tot tell the difference in the finished results, but up close you can.
So it depends on the desired finished result which is "better" for you; for web viewing, basically, 8-bit is all you need. For making large prints of complex images, 16-bit has an advantage.
This is a gross oversimplification, but....
R.
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07/31/2007 09:14:22 PM · #7 |
| Even though it says 16bit in PS, most cameras are only 12bit. |
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07/31/2007 09:37:49 PM · #8 |
| What if the original is only 8 bit? For example, If I take an image from dpchallenge, it has been converted to 8-bit for posting. But the option for 16 bit editing is still available from photoshop. How does photoshop replace the missing bits? |
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07/31/2007 09:54:37 PM · #9 |
Guess I stumped everyone.
I'm pretty awseome, I know ;) |
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07/31/2007 10:02:18 PM · #10 |
| so its like nintendo vs. super nintendo |
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07/31/2007 11:00:45 PM · #11 |
Originally posted by LanndonKane:
What if the original is only 8 bit? For example, If I take an image from dpchallenge, it has been converted to 8-bit for posting. But the option for 16 bit editing is still available from photoshop. How does photoshop replace the missing bits? |
I believe the answer is no. That to gain the advantages of 16-bit, you really need to start with a greater-than-8-bit source file.
BUT ... I have always wondered ... if you know you're going to do extreme changes in hue/sat/levels adjustments, do you gain anything by switching to 16-bit mode so that those changes can have more even steps within them? I know you can't invent data that was never there. But what if the hue/sat/levels had a bigger palette across which to spread its adjustments, would it make a difference?
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07/31/2007 11:15:49 PM · #12 |
Originally posted by electrolost:
so its like nintendo vs. super nintendo |
so how many bit is the ps3 or xbox360? ;) |
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07/31/2007 11:19:34 PM · #13 |
Originally posted by crayon:
Originally posted by electrolost:
so its like nintendo vs. super nintendo |
so how many bit is the ps3 or xbox360? ;) |
Notsure but:
PS2 was a 300mhz 128 bit processor while Xbox had a 733mhz 32 bit pentium 3. The Playstation could out process the xbox mathematically 2.5 times. But suffered from having half the ram and a less competent video card.
I know the PS3 has a 9 Core Power PC Processor that runs at 3.2ghz. |
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08/02/2007 08:24:57 AM · #14 |
Originally posted by cloudsme:
Even though it says 16bit in PS, most cameras are only 12bit. |
MKIII is 14
medium format backs are true 16
either way makes a hell of a difference when tweeking ;) |
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08/02/2007 08:32:09 AM · #15 |
The cheap version of Neat Image only handles 8-bit.
So am I better off doing my noise reduction first before tonal changes, which means I need to convert to 8-bit, or am I better off doing tonal changes, which might brighten noise, and then converting to 8-bit afterward, then doing noise reduction?
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08/02/2007 10:18:37 AM · #16 |
Originally posted by levyj413:
The cheap version of Neat Image only handles 8-bit.
So am I better off doing my noise reduction first before tonal changes, which means I need to convert to 8-bit, or am I better off doing tonal changes, which might brighten noise, and then converting to 8-bit afterward, then doing noise reduction? |
In general noise reduction should be done first since other processing could enhance the noise making the job of reducing it later a lot harder.
Best solution, get the version of NI that handles 16 bit or use your editing software to do some initial noise reduction before other processing then convert to 8 bit and do any final noise reduction in NI. |
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08/02/2007 10:30:29 AM · #17 |
Originally posted by dwterry:
BUT ... I have always wondered ... if you know you're going to do extreme changes in hue/sat/levels adjustments, do you gain anything by switching to 16-bit mode so that those changes can have more even steps within them? I know you can't invent data that was never there. But what if the hue/sat/levels had a bigger palette across which to spread its adjustments, would it make a difference? |
I have always wondered this myself, and I think it depends on Photoshop and your editing practices.
If you use a bunch of adjustment layers, I assume PS is smart enough to process all these together in a lossless manner, then apply it to the image as a last step. This would mean that editing an 8-bit original in 16-bit mode wouldn't help any.
However, if you paint on the image, or use adjustments to the pixels (not adjustment layers), I assume the data is all truncated to 8 bits. In this case, it would probably be marginally better to edit in 16-bit mode.
I suppose this could be determined experimentally. Maybe I'll get back to you. =) |
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