I'm (ever so slowly) putting together a page of self-publishing FAQ, and I'd like to share a section here. There are a number of things to keep in mind from the onset when creating a graphic novel with print in mind, and here's my experience of them. Some may vary and I may have left stuff out, please add to the list if you think of something!

Resolution: Files to be printed need to have a resolution of 300 dpi. POD may accept resolutions as low as 150, but don't go for it. Most industry printers, including digital, will produce horrible results at less than 300, so play it safe. On the other hand, it seems unnecessary and unwieldy to work at higher resolutions, unless you have specific needs and know what you're doing.

Page size: Work at a larger size than your desired print size. My printed volume is A4, but my files are A3. You never know when you're going to want a larger version of a page. Out of the blue I was recently asked for large prints of my pages for 2 separate exhibits, so that really paid off.

Speech balloons: I profess planning the speech balloons early on in the layout of your page as opposed to pasting them on top of the artwork wherever you can, as is too often done in the mass comic industry. However, it is a really good idea to keep them on a separate layer from the art anyway. It took me 2 volumes to learn that lesson and now I really wish I had done this from the start. Again, you may find yourself wanting to print the art on its own. Or you may want to use a certain frame from a page for other purposes, and if there's a balloon in the way that means you have to retouch the panel separately. Finally, if you ever translate your book to another language, you may bitterly regret not being able to enlarge those damn things with ease...

Color space: Work on the screen is in RGB mode, but printing is done in CMYK if you're going for offset. Don't make the mistake of simply converting your RGB files to CMYK. That will add black to all your colors. Seriously, do not do this. You can leave the conversion to the printer, which they will charge you as "color correction", but this can be worth it for a real good result. Or, you can ask your printer for a color profile that you can use to convert your pages with the least possible loss.*
This profile (something.icc) should be saved where you won't misplace it (I keep it in with my work files). To apply it, open the file you wish to convert and go Edit>Convert to Profile. Select your profile and you'll be asked whether to flatten the document. I recommend flattening so that any blend modes you have don't go all funky on you. Save as a copy, and review the page for anything that may need resaturating (usually only needed if you have light effects, see below)

*Some loss is inevitable, because a printed page is subject to the limitations of actual ink printed on paper. Not all colors on the screen can be reproduced with a CMYK process! For instance, I make extensive use of the Color Dodge and Linear Dodge blending modes to obtain the green light effects of my character's power. In print the glow is lost no matter what; all I can do is resaturate the green as much as I can after the color conversion. Eventually it does look fine because when reading the printed version you're not comparing with the screen version, and your eyes still pick up a glow. Just remember there will be some loss to compensante for.

Margins and bleeds: In a printed page, the inner edge gets eaten up by the binding and the outer edge by the cutting, especially if the volume is saddle-bound (stapled). Perfect binding eats up at least .5 cm of the inner margin. Plan accordingly and use wide margins so that the page looks right after being thus diminished, no less than 1.5 cm on each side – 2 or 2.5 are better. If the art in your comic touches the edge of the page, it is said to "bleed". In this case, the art needs to extend beyond the page so that if the cutting is not accurate (it NEVER is in the real world) you won't end up with a white line on the edge of your page. It is standard to have a 3 mm bleed, so you need to add 3 mm to your page size (on each side that gets cut) before you even start working. Let me illustrate this. Suppose your page is 20x30cm. Your work file will be 20.3x30.6 cm (3 extra mm on each side except the inside). Use guidelines to define the page's "real edges". Inside this, with at least 1.5 cm margin, add another set of guidelines to indicate the surface your panels can occupy. Personally, I add the bleed on ALL sides, so I only have to deal with one page template. The unnecessary inside bleed can just be left out when you place your files in your publishing software.
Careful! The bleed needs to be 3mm on your printing size. If you're working larger, you have to increase it so that it becomes 3mm when shrunk. I learned that too the hard way!

Page position: It doesn't matter online, but in a book, a given page will be on the right or left, and it matters a great deal! Your story will be enhanced or weakened, depending on whether you plan for this or neglect it. For instance, I keep all my cliffhangers at the bottom of the right-hand page, so that the reader doesn't discover what happens before they turn the page. If you have a splash page, you have to arrange it so that the previous page is on the right as well (unlike a commercial comic, you can't insert an ad where it's convenient). This must be planned for in the very early stages.

On the resolution thing-- a lot of publishers want different resolutions for color vs greyscale vs b/w work.

Tokyopop, when they were taking submissions, asked for 600 for contest entries, and 1200 b&w for their OGNs.
Zuda wanted 600 dpi for all comics, color or not. The digital publishers/distributors I'm working with now generally want 300dpi.

Yeah but those represent the special cases I mentioned. If you're self-publishing, there's really no point.

Great tips!!! Everything is in metric!!!! Darn you doing things the non-American way! haha I actually prefer working in Metric. My grids are always based on 10s. Sooooo easy.

I have some more tips to expand on that. Don't just think you can take your 72dpi image off your comic blog and "rez it up" to 300 dpi. Thats an amateur move. You'll get chunky, gross looking pixels and bad quality. You need to scan or create work that is larger than or the size of your page. So if your page size is 10.125" tall (with bleed) you need artwork that is scanned at 10.125" tall @300 dpi CMYK. You will get very very large files especially if you are in a non compressed format that you should be working with, but its what you need to do to get great results. Don't be surprised if your GN print ready file is several Hundred MB to even a Gig or two.

DO NOT PRINT WITH JPEGS FOR ANY REASON. Jpeg is not a print file...its an email/internet file. It compresses all your data and throws information out so it can be squished down. Moreover, some prepress programs have problems with Jpegs....your printer will usually not like those files. You want to use an uncompressed industry standard format like a .PSD or .Tiff for best results.

When laying out your book in InDesign, working with those large files gets memory intensive. Set your display performance to a lower setting, so you're not writing the full size image on screen if you have RAM issues. That helps a lot. Its ok to have JPEGS for FPO layout purposes, but be sure to place them out with final Tiff's or PSD's later. I actually use this as part of my final checks and balances system. If i see any JPEGS in my links palette than i know its an FPO RGB and it needs to be replaced. I only use TIFF and PSD in CMYK mode, so its a fast way to double check your work without going through preflight.

What about printing the pages out of order, so they'll be in order? That's pretty important. Sometimes.
Here's some help on that: http://www.dojranliev.com/?p=138

Here's a couple of interesting tidbits.

Depending on the print process, you don't really need more than 300 dpi for colour printing unless you have heavy photographic imagery. The additional pixel depth at 600dpi is good for obtaining the nuances in colours of photos - but you don't get the same effect with flat comics colour. Even something as intricate and colourful as Daniel Lieske's Wormwood imagery doesn't need it.

dpi stands for dots per inch. If you have a standard 6x9 page, with a character in a red jumpsuit with some shading and lighting effects, and this artwork is done at 600dpi, that is complete ink overkill. You are basically saturating that square inch with solid red ink. The same goes for black and white comics. Provided your artwork isn't scratchy or blurry, your work will render just fine at 300dpi than at 600dpi. The difference to the naked eye is negligible. It is like a HD tv set with 1080p vs one that is 720p depending on how close you are sitting to the screen and the size of it.

And to elaborate on Joumana's point about CMYK vs RGB. You can quickly test how your page will look in Photoshop by selecting Proof Colors in the View menu. You'll notice the saturation of your blues, greens and oranges primarily diminish. As a rule of thumb, if I'm working on something meant for print, I set it up in CMYK right off the bat - unless I'm using solid RGB colors that remain within the gamut of CMYK. You can also find out if your colours are outside of the gamut (range) by selecting Gamut Warning from the View menu.

what you're talking about is pagination for a saddle stitch type booklet (i.e. most printed floppy comics). The vast majority of printers DO NOT want you messing with that. Their pre-press setups have different workflows and what not that do all that stuff for you that is optimized for their machine.

Always talk to the printer about how they want the PDF set up or how they want delivery. (my last print job last week, the printer won't accept any PDFs...just a packaged indesign file...they handle all that for me), but for the most part, give them a PDF in single pages that is in the exact page order you want it, unless they give you specific instructions.

No no, that's definitely not something you should do yourself unless you're printing the book from your own desktop printer. Let the printer worry about that, they just want your InDesign file or press-ready pdf, as Chris pointed out.

Chris and Drezz, thanks for expanding! And you reminded me what a relief it is to be able to just use psd now in Indesign, as opposed to eps for Quark!

As a person working in printing, looking at good and bad files all day, I have a few things to say about resolution (as this is something that makes my eyes twitch on a daily basis):

The sharper your image, the higher your resolution needs to be. That minute stair-step edge formed by the pixels is more obvious the higher the contrast is along edges. So for most comics, with cell-shading, nice crisp lineart, and text, the higher the res (600 is great. 1200 starts to kill some people's computers), the better your bases are covered. Using the excuse of "I'm just a self-publisher, it's useless to me" is sort of a misleading statement. Even Kinkos prints will look better at a higher resolution.

Softer shading doesn't require as high of a res. It will also accept up-ressing better. Especially through Photoshop (the newer the version, the better up-ressed images look)

The smaller the final product, and the more closely it'll be scrutinized, the higher the resolution. My previous job had me printing tiny things. Nothing larger than an 8.5x11" sheet. Some as small as .25" x .25" (I was printing labels and tags). The lower the resolution, the less ability I had to make sure the customer's files printed well. And we were just running a standard business-grade color-copier! (grant you, those run 20k these days!) We requested 600dpi, accepted 300 dpi, and raised a red flag to any customers submitting artwork below 300. At my current job, we won't actually ACCEPT art over 150 dpi. But we're also printing large-format fabric. The RIP software can't handle 600 dots per inch when you're covering ONE THOUSAND SQUARE INCHES.

In summary? the higher a resolution you can work the better. Anything you can keep in vector format, the better (if you even ARE working in vectors). This includes live fonts aligned in files.

I save all my line art as 600dpi and my grays as 300dpi, then composite then in InDesign. Like plotholetsi said this makes a difference even if you're printing at Kinko's. I haven't used a POD place yet and I know they usually ask for one 300dpi tif or whatever. The linework is not going to be as crisp this way but for most people not a dealbreaker either. But I think assuming you'll only need 300dpi for everything could be a mistake down the road if you decide to go a different route in publishing later on. Better to have the hi-res than to not and from everything I've read 600dpi seems to be the standard for black and white line art/ 300 for color.

These are all great tips! Thanks!

600 dpi is better for black and white, linework and the like, yes. But the offset printers I work with don't take 600 for photos or artwork. They recommend 300-350 but if you give higher, they will shrink it to 350 in any case.

Well, another small benefit of working at a higher resolution is that if you work larger and then shrink, it ALWAYS looks better than if you initially worked at a smaller size/resolution. It just does. Sometimes it doesn't seem logical, but that's how it works out.

That's assuming your work is entirely digital. Mine is not, so I work at double my final print size. At the level of the file it's the same result, but obviously I can't work on A4-sized originals. Most artists work on a larger scale in any case, knowing that reproduction on a smaller size then tightens the details.

That's weird. When I select "Proof Colours" in the menu, absolutely nothing changes. But when I select "Gamut Warning" some parts of the sky become gray. Should I worry?

Also, I draw on A4 paper, scan in 600dpi, and after cleaning up the lineart I change the resolution to 300dpi, and then start colouring. I use insane amounts of layers when colouring, so doing it in 600dpi would kill my computer. I intend to print in A5 size, so 300dpi A4 pages are large enough, right?

More than enough. My printer reduces it to 350 anyway: a higher res than that is not useful except in very specific kinds of work (and one is not likely to do that kind of work and not know they require specially high resolution). Since he told me this, and as I work my digital files at 300 A3, I reduce them in size and increase them in resolution myself before sending the files. I don't have to but it makes for a lighter package. It was not a problem when I handed in 300dpi A4s, though, that makes only a fine difference in print.

Oh man - thanks very much for this thread, guys! This will certainly save many headaches and heartaches later on.

Just to clarify: if I'm working at double size, 300dpi should be tons for most printers, shouldn't it?

One thing I'd like to add is that if you're in Australia or elsewhere, 'bleed area' can sometimes need as much as 5mm extra all around. I guess double checking with your printer about their particular requirements is the most sensible thing to do.

In regards to the resolution / dpi discussion here, digital lettering can get funky if it's resized. So if you made your files at an A3 and then you sized down to A4, you could end up with pixelation if your lettering was done at the A3 size. It's usually better to letter the pages at whatever your print size is going to be, regardless of the size of your artwork page. And it's something that you should spot right away, so hopefully no one has fallen over on this one.

This hasn't been an issue for me (no pixeling when sizing down) but I think it's wise advice worth underlining nevertheless. I now redo my final lettering in InDesign at the printing size, so the text is razor-sharp when the pdf is exported.

I think that it's something mostly dealt with if you're going to a third party printer.

I was hand lettering for a long time, so it was a negative issue for me, but then I decided that I wanted to have the polish of digital lettering (and my consistency on hand lettering wasn't improving fast enough), so I started thinking of it like this.

How do you do your balloons? InDesign? I'm on a rickety, ancient version of the CS - CS2, in fact - so I'm not sure which program people are using for what anymore.