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Another 8/16 bits question

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  #1  
Old 08-31-2011, 04:50 AM
Dropt Dropt is offline
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Another 8/16 bits question

Good morning everyone,

As there is no small questions thread, I find myself opening up a whole new subject for a small question. Here's the deal and it's quite simple : My boss has given me a 16 bits camera file to convert in 8 bits, then retouch. So far so good. But he's also adding (quoted here) "the files are 16 bits, first I increase the physical size by two then I step down to 8 bit files... please follow this always as the depth of the pixels in shadows and highlight will suffer otherwise".

I suspect him to have no ideas of what he's talking about, as he's no brilliant retoucher or anything near that. I've red quite a few arguments about 8 vs 16 bits here and on the internet, but never something likewise. I understand that 16 bits creates more tonal range, so I guess it's about conserving them in his sayings, but anyway it all comes down to a 256 levels range in 8 bits, so what's the point ? It's not like the resolution change between 8 and 16 bits.
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Old 08-31-2011, 05:21 AM
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Re: Another 8/16 bits question

IMO if you are given a 16 bit file to work on then it is preferable to edit at 16 bit depth and only convert to 8 bits after your editing manipulations prior to output.

I cannot see how increasing the physical size size of a 16 bit file by a factor of 2 actually gives any benefit - the bit depth and the levels you have to play with (shadows and highlights included) remains the same, the file size will be larger but no true gains to resolution as the increase in size has been accomplished by software interpolation.
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Old 08-31-2011, 06:09 AM
Dropt Dropt is offline
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Re: Another 8/16 bits question

I agree entirely with your first statement, also the pic is to merged with others which are in 8 bits, so I had to downgrade it pretty quickly. Also I could've taken all the other files to 16 bits, that was easier to do the first take for practical reasons.

Thanks for confirming my doubts, that just made no sense to me...
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Old 08-31-2011, 09:22 AM
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Re: Another 8/16 bits question

Quote:
Originally Posted by Dropt View Post
I understand that 16 bits creates more tonal range, so I guess it's about conserving them in his sayings, but anyway it all comes down to a 256 levels range in 8 bits, so what's the point ? It's not like the resolution change between 8 and 16 bits.
It doesn’t provide more tonal range. The range is the range.
Think of this like a staircase. The height of the staircase is what it is (the tonal range). The number of steps in that staircase is the bit depth. You can have a 9 stop staircase height with 8 steps (bit depth) or 16 steps. But that doesn’t change the tonal range.

If given 16-bit data, keep it in 16-bit data forever (or save off an iteration in 8-bits per color if necessary while retaining the high bit archive).
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Old 08-31-2011, 10:54 AM
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Re: Another 8/16 bits question

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Originally Posted by andrewrodney View Post
It doesn’t provide more tonal range. The range is the range.
Think of this like a staircase. The height of the staircase is what it is (the tonal range). The number of steps in that staircase is the bit depth. You can have a 9 stop staircase height with 8 steps (bit depth) or 16 steps. But that doesn’t change the tonal range.

If given 16-bit data, keep it in 16-bit data forever (or save off an iteration in 8-bits per color if necessary while retaining the high bit archive).
+1; A really great analogy
Regards, Murray
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Old 08-31-2011, 11:28 AM
Dropt Dropt is offline
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Re: Another 8/16 bits question

Re-thinking about it, the tonal range is indeed still the same. I mixed tone and color range here, how stupid. Thank you Andrew.

Last edited by Dropt; 08-31-2011 at 11:51 AM.
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Old 09-01-2011, 01:59 PM
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Re: Another 8/16 bits question

I had a nice long answer for you, but for some reason, my login had timed out by the time I hit submit. I hate it when that happens.

Longer story shorter. You are right.

I agree with the 16 bit suggestions put forth here if you are working with imagery for photographic output.

But if you are in advertising like me - then cut to the chase. Convert it to 8 bit right out the gate. You will hardly ever even notice any differences. You are going to press and are going to be dealing with CMYK conversion and out of gamut issues anyway. You'll work on smaller files, get done faster and make your deadlines easier.

In any event, you boss is whacky and is confusing some resolution issues with color depth ones. His process will do absolutely nothing good and may in fact, end up softening the end image.
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Old 09-02-2011, 11:56 PM
Flashtones Flashtones is offline
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Re: Another 8/16 bits question

Quote:
Originally Posted by Dropt View Post
My boss has given me a 16 bits camera file to convert in 8 bits, then retouch. So far so good. But he's also adding (quoted here) "the files are 16 bits, first I increase the physical size by two then I step down to 8 bit files... please follow this always as the depth of the pixels in shadows and highlight will suffer otherwise".
It sounds to me like your boss wants to end up with a file uprezed to contain twice as many pixels, and would like you to the uprez in 16 bits before beginning retouching rather than after.

Uprez first, then retouch.

Seems like a fair and simple enough request. If his testing bears this out as superior, so be it. I doubt the reverse would prove itself better. I'd prefer to sharpen and clone, etc, at size rather than uprez any flawed retouching.
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Old 09-03-2011, 03:29 PM
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Re: Another 8/16 bits question

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Originally Posted by Flashtones View Post
It sounds to me like your boss wants to end up with a file uprezed to contain twice as many pixels, and would like you to the uprez in 16 bits before beginning retouching rather than after.

Uprez first, then retouch.

Seems like a fair and simple enough request. If his testing bears this out as superior, so be it. I doubt the reverse would prove itself better. I'd prefer to sharpen and clone, etc, at size rather than uprez any flawed retouching.
While appreciate your thinking and agree with you on the facts, I don't however think that is what her boss is thinking. I say that because it sounds like she is getting pretty hires (16 bit to boot) files as her originals to start with. I seriously doubt that there may be anything of any significance gained, or lost in the process. And sharpening can be harder to control, and even cause a graininess in a large file with lots and lots and lots of pixels. And she says that her boss' "formula" is in response to her having to convert to 8 bit eventually - so I really think he thinks he is counteracting the effect of the 16 bit to 8, by upsizing by a factor of 2. Not doing what he thinks - and is just likely wasting time and losing money.
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Old 09-03-2011, 05:43 PM
Flashtones Flashtones is offline
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Re: Another 8/16 bits question

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Originally Posted by daygraphics View Post
I don't however think that is what her boss is thinking. I say that because it sounds like she is getting pretty hires (16 bit to boot) files as her originals to start with.
"My boss has given me a 16 bits camera file to convert in 8 bits, then retouch. So far so good. But he's also adding (quoted here) "the files are 16 bits, first I increase the physical size by two then I step down to 8 bit files... please follow this always..."

I don't see anything indicating hires from the OP, and what does "hires" even mean"? Where exactly is the dividing line between hires and low res? If the res is so high why do they need to step it up? And what assumptions about output size and resolution are you working from?

While we're at it, what assumptions are you making about the OP's computer, RAM, storage capacity, etc. to justify going against their bosses explicit instructions to upres in 16 bits before stepping down to 8?

Quote:
I seriously doubt that there may be anything of any significance gained, or lost in the process. And sharpening can be harder to control, and even cause a graininess in a large file with lots and lots and lots of pixels.
Wow that a lot of assumed pixels. How many are we talking about here?

Quote:
And she says that her boss' "formula" is in response to her having to convert to 8 bit eventually - so I really think he thinks he is counteracting the effect of the 16 bit to 8, by upsizing by a factor of 2. Not doing what he thinks - and is just likely wasting time and losing money.
I think he believes there will be less rounding errors by uprezing in the native 16 bits. While it's debatable (and testable,) whether or not it yields a visible advantage, I see no reason to defy one's boss over it. Even marginally inferior results will rest solely on the shoulders of the employee. One has to make a lot of assumptions to justify the risk.
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