Ok.... So Photoshop is an 8-bit color depth program...

Ok.... So Photoshop is an 24-bit color depth program...
(changed title so that the very technical minded won't be offended by my less than totally understanding line of thought)

Which means it handles 8 bits per channel, or a 256 color level gradient.

I know Photoshop can convert channels to 16 bit, but have read that no real editing can be done at this high level of color.

I'm merely wondering because I notice on really high DPI pictures I create, I can see banding in RGB/CMYK/LAB color if fine gradients are used. Sometimes, even less DPI, I can see this occur.

My question then is. What can/do I need to do to attempt color editing at 48-bit color/16 bits per channel color depth (or even 30-bit/10 bits per channel)? And if Photoshop can't handle such editing, what does?

Another update. Macromedia Fireworks manipulates images in the .PNG format (the PNG format can handle 48-bit/16 bit channels), but I don't exactly know if it can actually open/edit .PNG files at that depth.

Edit: Well, I just tried it. An image converted to 16 bit channels, and Photoshop gave me this error message when trying to use the move tool.

"Could not use the move tool because it does not work with 16 bit per channel images (convert image to 8 bit per channel to edit)"

To me, this seems like a big weakness of Photoshop. I know a lot of professional editing equipment uses 30-bit (10 bit channels or 1024 levels compared to 256). So when does Adobe rectify this issue? And if there is an image editing program that can handle this color mode, by all means please let me know.

Of course, regular computer monitors only show 24-bit color depth, but I can "still" see banding if gradients are too fine on large images.

Yes this is an issue which some people have "dissapeared up their arses over" for a long time.

Actually is you have any kind of problem with banding or crude data then 99 times out of 100 there will be a solution in 8 bit! TECHNICALLY speaking there is a difference in 16 bit mode but you would be very hard pushed to spot it. Some ultra high end people do as much editing in 16 bit before converting to 8 bit for final retouch.

I think there is Barco Creator or something which will handle 16 bit - but its actually far less powerful than PS because it doesnt have half the tools, or flexibility.

If you check the histograms to make sure that your gradients and editing is smooth then you will be OK. Also remember you should have your resampling set to BICUBIC. Remember also that probably 99% of the best retouchers in the world use Photoshop, and have no real problems - the levels of adjustment possible are incredibly subtle in PS.

I usually add a little noise to my gradients for print. It kills most of the banding, and like mark said, check the histogram. A smooth slope with generate a smooth gradient.

Yes, I've used noise as an attempt to cover up banding before, I just was hoping there was a bit more of a solution.

As for using histograms as a method of seeing how smooth your gradients are, I'm not certain how one goes about adusting a super-fine gradient fill to look any better with the histogram or adjusting levels. I've noticed adjusting levels removes lighter/darker pixels, but thats about it. But I will look into seeing how much this suggestions proves of usefulness.

Still, having a true 48-bit graphics editor would be nice. As I would no longer have to find workarounds for 24-bit banding issues. I eagerly await the day that one (other than the Barco one) is made.

If only it did 30-bit editing, so that my Intuos would have an actual reason to have 1024 levels of pressure. I take it that with the current state of Photoshop and even programs like Painter, that pressure sensitivity can only be sensed up to 256 levels, since gradients can go no farther. I guess this is sound reasoning comparing the 1024 pressure levels on a Wacom Intuos tablet to the 256 levels of gradient a picture can currently use.

The curves pallet.
Thats where I make my adjustments when I am searching out a single value. You can nail down "certain" pixels in there, its tedious, and generally sucks... but its possible... and at times necessary

Really though, I just trust the "info" "levels" "curves" pallets in photoshop and the RIP when I print the piece, and finally the imagesetter that prints the film. (ALL of which "I" am in complete control of)No matter what I might see on screen I trust my equipment. I print at 175 LPI generated at 2540 DPI (or 150 LPI at the same resolution) banding is rarely a problem.

I know you are knowledgeable about this stuff, just based on your answers all over this forum, and I'm sure I ain't answering your original question. I've just never had any HUGE issues with banding.

Usually if it is only "mildly" visible on the screen it ISN'T"T visible on the film or finished product. I have received files from people that have horrid banding issues, but who knows what happened to that poor defenseless file before it found it's way to me. ;)

Really, my coworkers/friends/whomever never notice the banding going on in some of my work, its just me, but I do notice it. I just have an extreme and critical eye on what I do.

That's ANAL.... I mean... COMMENDABLE! :D

HEHE!
I know exactly what you mean, I am SUPER critical of my own stuff.

BUT, I do have this one customer, he is REALLY critical of EVERYTHING. He does his own artwork for everything he prints with us, and doesn't mind "PAYING" for us to give him extra attention. I told him one time (a long time ago, before I really knew him):

"Dave, when you die and go to HELL, the devil is gonna make you color correct, strip and print your own JOB!"

He still reminds me of that almost monthly.

I once worked with a guy who was sooooooo anal he was almost impossible to work with;

1 He couldnt design his way out of a paper bag (thats just an expression I made up one time sorry) - no visual imagination whatsoever.

2 He was mainly a Quark Xpress man - spent ages kerning letters on headlines - main problem was he`d chosen some dodgy font which made the whole ad look amateur. No excuse when you've been doing it for 20 years.

3 Head full of "design rules" - most of them concieved in the late 70's, and absolutely outdated. Every ad regarless of the client or the product was almost a carbon copy of the last.

The lesson I think is - There is NO substuitute for talent - no amount of anal attention to detail is a substitute, you can train a chimp to do that stuff! Quality has VERY little to do with "up your arse" issues like minor gradient banding and .001 of a point between letters. The skill IMHO is to be able to step back and try to take a broader view - see whats really important.

- feel relieved been storing that one up for a while, hope its OK.

I definitely don't have a problem with that opinion. I like to think I'm anal with some talent. :D

I only really have to be critical about my print work. Web stuff, like my signature, I can accept .gif/.jpg noise, artifacts, and banding, it just starts to get me when print DPI starts to inflate and minor details suddenly become much more defined. I haven't had a client yet complain about banding, but whenever possible I keep that out of anything print related.

This is a little different but related subject...

I recently read an article about scanning 24-bit images (8 per channel) into photoshop. The article said that when you scan at 24-bit color, you don't really get 8 bits per channel, but actually somewhat less--5 - 6 bits of real information. The article implied that you should scan at 16 bits per channel instead, and then convert your image to 8-bits per channel via Image>Mode, the result of which would be a fuller range of color in your 8-bit image.
I'd like to maximize the color information I have, but I'll be printing to 8-bit devices. Would it be worth my while to scan at 16 bits even though I'd end up converting to 8 or was the author of this article misinformed?