For Photoshop banding, add a very small amount of spatter to disrupt the band. The problem may be with your printer using old technology, much of banding has gone away with improvement to dot structure.

ppi, dpi, lpi are not the same, but I don't mind if that is how you like to think of it. Just know that it usually takes more than one pixel to make a dot in printing, and the lpi you print at is very important to how fine your screen is.

I know there is a difference, but I don't see it. I think of pixels as dots.

And therein lies your problem. On the one hand, you say you want to understand banding so you can create graphics for remote use that you won't see, with confidence. On the other, you don't want to be bothered with things like correct terminology, the understanding of which is necessary to understanding banding.

To help you correct a few apparent (and quite common) misconceptions:

• Banding is a printing abberation. It results from the limitations of the output device in terms of levels of gray. Levels of gray is the count of differently-sized halftone dots that a given printing device can render at a given halftone frequency (LPI). Any given printing device can only print so many levels of gray, by far usually no more than 256, but dependent upon the screening method and settings used. In normal halftone printing, the higher the halftone ruling, the fewer levels of gray the device can render, and the greater the liklihood of banding.

• Using higher bit-depth (i.e.; the often trotted-out 16 bits per channel) will not improve the situation if the large format composite printer being used to print the trade show backdrop is still limited to 256 (or fewer) levels of gray per channel. In other words, merely creating and delivering a 16-bit image does not magically increase the rendering hardware resolution of the output device, which is really the source of banding.
• Raster images are no more immune to banding than are vector graphics.
• Adding noise may help disguise it, but only if the gray levels within the noise differ enough to cause "jumps" between different gray levels that the printing device can render. That intensity of noise may be entirely undesirable. Usually, adding subtle noise (as many often suggest) merely roughens the boundaries between visible bands a bit.
• The bands you see onscreen are not representative of the actual bands you will see in print. Your monitor is an entirely different kind of output device. It does not display multiple overlays of halftone (or stochastic) dots. It just colors a single grid of pixels, which is not at all the same thing as changing the sizes of halftone dots.
• Using stochastic (i.e.; FM) screening can theoretically reduce banding for a given resolution device, because all dots are the same size; the frequency of their occurrance--not their size--is what is modulated to simulate tones, and their patterning is semi-"random." That's similar in principle to adding noise to the print output.

So you really can't predict banding on a finished product to be rendered remotely and never seen, unless you understand toning methods and/or are aware of the specific device that will be doing the printing and at least conceptually understand its limitations.

If you're serious about it, you should confer with an output vendor who actually understands their output devices' capabilities and do some simple tests. Once you have a quality vendor, standardize on that vendor (or others that can be quantitatively verified as similarly capable) for all your remote uses.

JET