Switching between 8 or 16 bit...

[trink408]

How does switching back and forth between these two modes affect your image?

I'm curious if you work in 16 bit mode, save the adjusted file in 8 bit to save space, then come back to it for editing another day and switch back to 16 bit mode before editing what happens to the photo, does that affect the overall quality?

Thanks

[Joanna Carter]

If you scan an image in 16bit, then you will have more information than 8bit. If you then change to 8bit, you will lose detail which can not be recovered by converting back again.

[BarryS]

Once you've edited in 16 bit and convert to 8-bit--you loose data that doesn't come back if you convert to 16 bit again. There's very little advantage in converting back to 16 bit mode once you've gone to 8 bit and it doesn't make sense from a workflow standpoint. Hard drives are cheap and getting cheaper, why not just save a 16 bit version?

[trink408]

Thanks guys, that is exactly what I needed to know.

I have been editing and saving in 16 bit, but if you want to use certain filters, or save in some formats you must convert to 8 bit. I started wondering what happened when you switched to 8 bit for a certain function, then switched back to 16 bit.

I agree, disc space is cheap these days...:)

[sanking]

Once you've edited in 16 bit and convert to 8-bit--you loose data that doesn't come back if you convert to 16 bit again. There's very little advantage in converting back to 16 bit mode once you've gone to 8 bit and it doesn't make sense from a workflow standpoint. Hard drives are cheap and getting cheaper, why not just save a 16 bit version?

It is definitely better to edit and save your files in 16 bit, especially if you plan to do any further editing.

However, if you have already saved the file as 8 bit and open it again for editing there is some advantage to converting it to 16 bit. You don't recover the lost data but you won't lose as much in editing as you would if doing this in 8 bit.

Sandy King

[David Luttmann]

It is definitely better to edit and save your files in 16 bit, especially if you plan to do any further editing.

However, if you have already saved the file as 8 bit and open it again for editing there is some advantage to converting it to 16 bit. You don't recover the lost data but you won't lose as much in editing as you would if doing this in 8 bit.

Sandy King

What Sandy said.

Converting back to 16 bit will at least lessen bit rounding errors than by leaving it in 8 bit mode.

[trink408]

Also good to know since some of the functions require 8 bit mode, at least if I switch back into 16 bit it helps some...

Thanks everyone.

[Kirk Gittings]

Just curious. What functions that require switching into 8 bit mode are you referring to? In my workflow for fine art prints, I can stay in 16 bit right up to the final save????

[BarryS]

...

However, if you have already saved the file as 8 bit and open it again for editing there is some advantage to converting it to 16 bit. You don't recover the lost data but you won't lose as much in editing as you would if doing this in 8 bit.

Sandy King

Absolutely true, but any major manipulation of the image should be done in 16 bit mode prior to converting to 8 bit. Any processing done after converting to 8-bit should be kept to minor adjustments and in that case it's unlikely to see a significant difference between a file left in 8 bit and converted to 16 bit. But you're right, working at a deeper bit depth is sometimes preferable. For some video editing and color grading work I do, it's not uncommon to transcode an 8 bit video codec to something like Apple ProRes 422 which is 10 bits. Heavy color grading will produce less artifacts when done at a greater bit depth.

I stay in 16 bit until my images go to my Epson 8 bit print driver. It seems like the jury is still out on whether a 16 bit print driver makes much of a difference.

[Ken Lee]

Hey trink408 - I just gotta ask: Are both of your "avatar" images, of you ?

If so, then which one is more recent ?

[John Berry]

How does switching back and forth between these two modes affect your image?

I'm curious if you work in 16 bit mode, save the adjusted file in 8 bit to save space, then come back to it for editing another day and switch back to 16 bit mode before editing what happens to the photo, does that affect the overall quality?

Thanks Make a duplicate, convert it to 8 bit. Make a selection of what you want to work on it, and drop the selection back on your 16 bit image and make your adjustment.

[trink408]

Hey trink408 - I just gotta ask: Are both of your "avatar" images, of you ?

If so, then which one is more recent ?

Amazing what an apple a day can do for you huh... :rolleyes:

The one in my signature is me from a couple years ago, the other one makes me laugh.

[trink408]

I can see I have a lot to learn about photoshop...

I ran into a new frustration last night trying to print some of my images, I've mostly been just creating images for viewing on a monitor, not having to worry about the image size and if it will fit on any of the available paper output options... Struggling trying to crop them to fit standard formats.

[Joanna Carter]

I ran into a new frustration last night trying to print some of my images, I've mostly been just creating images for viewing on a monitor, not having to worry about the image size and if it will fit on any of the available paper output options... Struggling trying to crop them to fit standard formats.
Assuming you are using the CS... versions of Photoshop : select the Crop tool and enter the proportions you desire into the options palette; marquee the desired area and crop.
Then you need to go into the Image Size dialog and reset the resolution of the image to 240 or 300dpi (without resampling). You should now have an image of the correct proportions which you can then resize, either using Photoshop or, better still, Genuine Fractals.

[trink408]

Assuming you are using the CS... versions of Photoshop : select the Crop tool and enter the proportions you desire into the options palette; marquee the desired area and crop.
Then you need to go into the Image Size dialog and reset the resolution of the image to 240 or 300dpi (without resampling). You should now have an image of the correct proportions which you can then resize, either using Photoshop or, better still, Genuine Fractals.

Thanks.

I am using cs, what do you set the resolution at when doing the crop, or do you leave that field blank? Why reset resolution to 240 or 300?

Part of my problem is I can't fit what I want to include in my image into the area cropped to an 8x10 or 11x14...

[Joanna Carter]

I am using cs, what do you set the resolution at when doing the crop, or do you leave that field blank?
I don't set the resolution at all, I just set the dimensions (it doesn't matter whether you use inches or cm, all you want is the final proportions.


Why reset resolution to 240 or 300?
Assuming the image is originally set to 240 or 300, using the crop tool without setting the resolution will resize the image without resampling, thus giving you an image of the correct size but at a silly resolution; I use 4cm x 5cm and that can give me a cropped image with a resolution of a couple of thousands - this is why you have to resize to 240 or 300 without resampling, to get back the original resolution.
It is very important that you don't resample at the same time as cropping, especially if, like me, you use the better option of using Genuine Fractals for resizing.


Part of my problem is I can't fit what I want to include in my image into the area cropped to an 8x10 or 11x14...
Don't think of the crop as being a real-world measurement, it is not so much cropping as reproportioning to a given ratio; cropping to 4cm x 5cm will give the same results as cropping to 8" x 10" - as long as you don't resample and that you reset the resolution afterwards.

Does that make sense yet ? If not, I could always do some screen shots.

[trink408]

Thanks for all the info. I will work on some prints tonight and see what I come up with...

Kevin