8 bit vs 16 bit?

[Lani]

Just curious as to how much real difference processing in 16 bit makes. I have found that it is clogging up CS4 on my system, and is also a bit of a nuisance because not all tools are available in 16 bit.... so have changed my default to 8.

Not sure on the technicalities of the impact on image quality...can anyone explain if it makes a noticeable difference?

[mcdesign]

I was wondering the same thing Lani and it is a nuisance to have to change it before saving a jpeg! Margaret

[Lani]

I've given up on it atm so just sticking to 8 bit until I can get a faster system, or find out there is a definitive advantage in persisting with it.:)

[kiwi]

Id say based on inexperience and innuendo, heavily influenced my rumors and fickle forum chat by people with no real idea that unless you need to recover lost detail in the blacks or whites (and only gives a minor advantage in that) that it's not of any perceivable value

There are those of the school of thought that you should always shoot at 14 bit, RAW and Adobe RGB as losing any information in the file is an abomination.

[joffa]

It's got to do with the amount of colours that can be saved in the image.

8 bit images can have 256 colours per channel,

whereas 16 bit images can have 32,769 colours per channel.

http://www.photoshop-tutorials-plus.com/8-bit-and-16-bit.html

[pommie]

In real life if you are only going to do minor post work then 8 bit is ok, displaying in jpeg or printing with an inkjet is 8 bit anyway, but if you want to do a lot of manipulation then 16 bit is better, as any manipulation you do will cost you some information so the more you start with the more quality you retain.

Cheers David

[arthurking83]

As Joffa said, (and it's my understanding that) the advantage is basically seen in high quality large prints, and that graduations in tones are the most obvious advantage.

never done any of that stuff yet... so it's based on the same innuendo and rumours that Darren's read about :D

[ricktas]

Joffa has got it partially right. 8-bit colours can have 256 brightness levels of each colour, 16 bit can have up to around 65,000

When you go from 16 bit to 8 bit, software generally dumps all the shades of a colour that it cannot display and moves them to the nearest one it can. If you later upgrade the photo back to 16 bit, you do not get the dumped shades back.

At present, when you have completed your processing there is no reason not to have an 8 bit version for printing as current printers can only print at 8 bit anyway. However this may not be true in future.

So in the end, it depends, would you be happy with 256 shades of a colour being available or over 65,000? Certainly with current printer technology, you are not gaining an advantage by printing a 16 bit photo over an 8 bit one, but the future could be different, and if you have all your photos at 8 bit, you may not be able to take advantage of printer tech advancements.

[Lani]

Thanks guys, and Rick particularly, for explaining it so clearly. I guess then it would be good to aim for 16bit processing for high quality images, and I would imagine then not only will printer improvements have an impact, but also software refinements down the track....sort of future proofing.
My system can't cope with it for some reason so it will have to wait for now....thanks again for clearing it up for me. :)

[ricktas]

PS: HDR are 32 bit images

[Kym]

Memory and disk are getting cheaper. Keep as much information as you can. As explained 16bits has a lot more information per channel (256 times as much, not just double).
As technology changes and improves that extra data will become useful.

[kiwi]

It's not so much the file size is why I don't bother its also the longer time the files take to write to the buffer, transfer onto the PC, open in Pox Shop etc

I seriously doubt I'll open up an image taken now in 5 years time when printer technology has "arrived" and need that additional capability. By then also editing programs will be that much better that youlll probably be able to achieve similar results anyhow.

[Shane]

I use Elements 7. Where ever possible I leave files as 16 bit. This is where I do minimal PP, that is universal changes to the whole image. If I use selections or layers I have to change to 8 bit or the program can't handle it.

[jjphoto]

In my experience it's a waste of time and space. I used to send jobs to magazines as 16bit Tiffs until I found out they were often being converted down to 8 bit! I only work in 8 bit now.

JJ

[wideangle]

Hi Lani - I have always worked with 16bit images for the reasons others have pointed out in relation to having more colour range to play with. Prints at this stage are by in large limited to 8bit output, but things will probably change in the future. I convert to 8bit for printing, but preserve my final edited photos in 16bit.

[BJI]

Shooting in 16bit (14bit) vs 8bit may be a debatable advantage but there is a significant advantage to working in 16 bit once inside your PC. If you have a histogram view in your software and do a few simple mods which change brightness levels of various pixels in 8bit you can very quickly see a comb like affect appearing meaning that out of the 256 brightness levels you have, a good portion are not being used to full advantage anymore which makes the gradations when printing more obvious.

Best to work on the PC in 16 bit with all the tools that support it and downsample it to 8bit when finished or for printing or sending to publishers, or when you must have a function that only works in 8 bit.

[pgbphotographytas]

Hi Lani - I have always worked with 16bit images for the reasons others have pointed out in relation to having more colour range to play with. Prints at this stage are by in large limited to 8bit output, but things will probably change in the future. I convert to 8bit for printing, but preserve my final edited photos in 16bit.

I think 8 bit for day to day stuff and 16 bit for another you might want to print in the future.

Paul

[Lani]

Thanks for your input everyone,I have just decided to bite the bullet and upgrade my system, so then I will have the choice to utilize 16 bit when the application warrants it. :)

[pgbphotographytas]

Thanks for your input everyone,I have just decided to bite the bullet and upgrade my system, so then I will have the choice to utilize 16 bit when the application warrants it. :)

That does sound like the best idea Lani.

Paul

[Michael]

Whilst I guess most of the printers we use are only 8 bit, I think the Epson Stylus Photo R1900 & R2880 print in 16 bit ?(atleast if you are using Mac OS 10.5).
I wonder how long it will be before the PC users have mainstream 16 bit printers as above.