8 Bits, 16 Bits ? huh?

[brit41]

Can some one enlighten me on the basic difference between editing in 8 vs. 16 bit? I think one is less destructive than the other but what about when it comes to printing??

:0)

[iCe]

Ruh roh... the 8 vs 16, you can't tell the difference, yes you can, debate is about to begin.

I edit in 16 bit Pro Photo color space. My thought is that I want to edit using the maximum data available to me.

PS- Editing a raw file isn't destructive no matter what you use.

[SCone]

8 bit vs 16 bit - computer talk for how many "bits" are available for prcessing. 8 bits has 256 possible values, 16 bit has 65536 possible values. So if you are editing in 8 bits, color, depth and everything is limited to only 256 values.

[brit41]

Then will printing and output be different or the same?

[SCone]

Printing is still 8 bit, video will be the same (depends on your monitor)

Will you notice any difference???? Probably not

[AndrewCCM]

Depends on the printer, but most all I am aware of are 8bit... but colorspace makes just as much difference there too.

[Gambit]

What you're talking about here is color depth. 8-bit color is 256 red values * 256 green values * 256 blue values for a total of 16 million color combinations. If you have a photo with a lot of subtle shades of blue, you might notice a difference between processing it in 8-bit vs 16, depending on whether anything else downconverts the 16 to an 8 bit image. LCD screens do not have the color depth of CRTs, in general, which is the primary reason I've not yet switched to LCD and still have this big beast on my desk. Here's a little blurb from the glossary on a tech site I've come to trust over the years:

http://www.anandtech.com/displays/sh...spx?i=2935&p=2


Color Depth: Depending on the sort of work you're doing, the need for high precision color depths varies. Most displays have a set number of intensities that they can display for red, green, and blue, and this is almost always a power of 2. (Technically LCDs function by passing varying light intensities through a color filter, but the net result is the same.) A 6-bit display can show 26 (64) different intensities while an 8-bit display can do 28 (256) intensities. With separate RGB values, you can then cube that number to get the total color space. 643 = 262,144, 2563 = 16,777,216, etc. While most people will agree that 6-bit is insufficient - even with dithering to approximate a larger color space - anything more than 8-bit per channel output starts to become more hype than substance. Lower color depths can also result in banding, where the transitions between various colors become visible even when they're not supposed to be.

[iCe]

All things considered, unless you are ultra-turbo-picky, and have a need for the maximum color rendition possible AND believe that a CRT will maintain good color as it ages, Eizo's beat the socks off of having 12,000 pounds of radiation producing CRT on your desk.

[CarolynM]

Dumb Question Alert!

My digital camera creates jpegs only, so does that mean I am working in 8bits? (I am guessing that shooting in RAW gives one the option to work in either 16 or 8 bits as one chooses, is that correct or not?)
If needed info, my camera is Canon Powershot A650IS.
Just curious since I was reading this info.
Thanks!
CarolynM

[AndrewCCM]

Yes.. JPGs out your camera are 8bit.

[CarolynM]

Originally Posted by AndrewCCM

Yes.. JPGs out your camera are 8bit.

Thanks Andrew!

CarolynM

[SCone]

How I long for vinyl...............

[jeffkohn]

Originally Posted by SCone

Printing is still 8 bit, video will be the same (depends on your monitor)

Will you notice any difference???? Probably not

The Canon large-format printers are 16-bit, as are the newly announced Epsons. MacOS has a fully 16-bit printing pipeline I believe, and I'd be shocked if the next version of Windows doesn't. And I bet you HDMI 'deep color' support shows up in PC video cards and monitors before HDTV's. 16-bit support is going to be coming on strong in the coming years, so why not future proof the images you take today?

The biggest advantage right now in 16-bit is that it gives you more editing headroom. The number of levels in an 8-bit image is plenty enough to appear as continuous tone to the human eye. But when you edit an image in Photoshop/etc, many of those edits are destructive and reduce the number of levels in your image - especially big tonal adjustments (increasing contrast, boosting shadows, etc). So while 16-bit is overkill for an untouched image, using it for edits gives you the extra data to help produce a better final 8-bit image. Whether the difference is noticeable in the final result depends on a number of factors, but for some images and some types of edits it can make a real difference. With disks/memory/etc getting cheaper every day I'd rather just play it safe and stay in 16-bit as long as I can.

[Pat Perry]

With PSE6, I don't have the option of 16 bit TIFF's...only 8 bit. Is there a way to work around that?

[Duffy Pratt]

As a theoretical matter, you should get the best results using the most bits you can, and using the smallest color space that does not clip any of the channels and leaves you some room at the edges.

With more bits, you get finer gradations for each channel. Of course, almost no monitor will let you see the fine gradations that you are making. But the rounding errors made when performing an operation should be smaller, and this reduces the possibility of banding showing up.

With a smaller color space, the range of colors available is smaller, and that means that with the same number of gradations, the difference between two levels will be finer with a smaller color space.

In practice, there are other considerations. How fast is your computer? How much storage do you have? If those aren't concerns, then 16 bit is definitely the way to go. Then, how good is your printer and how willing are you to do soft (and possibly hard) proofing? Again, the better the printer and the more effort you are willing to put into a print, the more likely that 16 bit editing will pay off for you.

Personally, most of what I edit goes to e-mail or the web. For that, 8bit and sRGB or AdobeRGB is just fine. Next level up is basic 4x6 prints, and there's typically no need to get any more sophisticated. But for anything that would require bigger printing, I would start from RAW and used 16bit editing and a color space that didn't clip any of the colors. Those sorts of prints are pretty few for me, and I don't see any reason to complicate my ordinary procedures to accomodate them. That's been even more true since the latest advances in ACR, since now 80-90% of my editing is done in RAW.

Duffy