Need advise on preparing .ai files for print house for labels design

Question

Greetings!
I just got a freelance job to do label design for commercial products (cleaning, food products, etc).
Its a huge task as the company have lots of products in the market and they decided to drop the design
company that were doing the labels for them and hire me to be the main designer.
Since my main work with Illustrator and Photoshop is been for Web Design and screen graphics,
I am not sure how to use Illustrator CS5 the best way for preparing the final files to send to a print house
according to European or US norms, I would like to have some help from other users that maybe are experience with this kind of job.
My main concerns for now are:
1. Should I send .ai or .eps?
2. Pantones or CMYK ? And how to create the artboards that show the measures of the labels and the pantone colors palette
    (I have seen examples on some prints that have show me ), but have no idea if Illlustrator already have a template/tools for that.
3. About the size of the labels, if its a straight shape, like a square, you make the artboard on that size and just put some bleed,
    but since most products labels come in many shapes, how do you work around it?
   Since the artboard can´t have the same shape as the labels , will the white background being print?
4. When using effects like highlights, reflections, especially in Titles, how do you create the pantones for that ?
Hoping to have some help from the community here, you can send me some links, tuts,
everything that can help me to understand all this kind of process, I will be much appreciate.
Thanks!

Answer 1

Some of the following (but not all) repeats, but elaborates on or clarifies what others have said.
First, though: While I certainly don't mean to discourage you, you will be far better off getting started if you realize this:
Designing for commercial-quality print is a hugely different world from designing for the web. You are now dealing with characteristics and limitations of real-world, physical machines, inks, substrates, and many-step workflows. The most tragic (and potentially disasterous) error web-only designers (and their clients) make is naively thinking that moving from web design to print design is a simple lateral move involving nothing more than a few quick answers to a bullet list of questions (CMYK vs. spot, etc., etc.) If you fall into that camp, you are asking for serious and costly trouble.
A user forum like this is a very poor place to educate yourself. Forums like this are populated by more beginners than experts, many of whom are far too eager to post answers. More often than otherwise, answers are--if not downright wrong--not best-practice.
You need to gain a working knowledge of the printing processes with which you wll be dealing. Take a class at the local tech school. Visit the printing houses (and don't carry a designer's chip on your shoulder). Look for any opportunity to get your fingers dirty; offer to do some grunt-work in a press room to gain exposure. Read authoritative books on the subject.
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f1. Should I send .ai or .eps?
Nowadays, PDF is the preferred delivery format for whole documents. If the printing house is placing the artwork in a program that cannot place PDF as a spot graphic, it is conceivable that they may need EPS. Depends on the printing house's workflow. In print work, you need to communicate with the printing house--and you need to learn to speak their language.
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2. Pantones or CMYK ?
Don't say "Pantones." Pantone is a company. Say "spot color." Pantone makes both process and spot inks. Pantone is not the only source for spot color. Your question is "spot color or CMYK process." The answer depends on the specific project.
Labels may involve CMYK process, spot colors, or a combination of the two. You can't just add colors to your design willy-nilly. You have to plan and design for it. It depends on the printing budget, the printing capabilitites of the printing house, the printing method, and even the design (which may affect the substrate, which may not be suitable for process).
When designing for print, don't think in terms of colors. Always think in terms of inks, because that's what you're really dealing with. Each time you add an ink, you add a workflow process, and therefore cost. As soon as you add a number of inks in the design that exceeds the number of inkwells on the press on which it will be run, you have just necessitated another press pass.
Labels also commonly involve clear or translucent inks (varnishes), liquid lamination (flood or spot), metallic inks, and/or foils. Each of those count as an additional ink or even a different work process. Sometimes certain inks require drying time after previously-laid inks, which also affects costs.
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And how to create the artboards that show the measures of the labels and the pantone colors palette
Again, best practice depends on the printing house and its workflow. For example, it can be a no-brainer labor (i.e.; money) savings to gang multiple instances of a label design onto a design page (Artboard) set up to the size of the press sheet.
It can be advantageous to draw die cuts on a separate Layer, also ganged to match the artwork layout. Same may apply to foils, varnishes, and embosses. It's often advantageous to draw trim and fold marks in the bleed area of the page layout. It's often advantageous to add registration marks in a press-sheet layout.
Again, best-practice depends on the project--but the economical and turn-around advantages can be significant.
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(I have seen examples on some prints that have show me ), but have no idea if Illlustrator already have a template/tools for that.
Whenever you catch yourself thinking "I have no idea if Illustrator..."--read the instructions.
Most graphics programs (including Illustrator) provide options for including basic "printer marks"  (trim and registration marks, separation labels) outboard of the page size. That doesn't mean it isn't often advantageous to add your own. For example, the auto printer marks setting will only add one set of trim marks for the whole page. That's pretty useless in a multi-up layout, which is quite common in label design.
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...but since most products labels come in many shapes, how do you work around it?
Pages (Artboards in Illustrator) are rectangular. One typically provides die cuts (and/or varnishes, foils, embosses, etc., etc.)  as elements drawn accurately on a Layer dedicated to the purpose.
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Since the artboard can´t have the are same shape as the labels , will the white background being print?
There is no "background." This is an object-based program. Where there is no object, there is nothing. By default, even white fills don't mean "white ink"; they mean "no ink." (Remember, think inks, not colors.)
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4. When using effects like highlights, reflections, especially in Titles, how do you create the pantones for that ?
Illustrator is primarily a vector based drawing program. Vector graphics are by nature and even by definition sharp edged. When vector programs try to provide "soft & fuzzy" features, they do it in either of two ways: either by programmatically creating additional vector paths and parameters (blends, grads, mesh grads), or by resorting to creation of non-vector "effects" (raster images). Whether such features correctly handle spot colors depends on the feature, and even on the version of the program.
So whenever working with spot color--in any program--you have to stay consciously aware of what you are actually doing (what kind of objects you are creating) when you apply such features. That's why it does no good in a user forum to speak of nebuous designerly terms like "highlights" when you ask technical questions. In order to get a correct answer, you ultimately have to state the kind of objects you are dealing with (and feature, and version, etc.).
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1. PDF?? I only use .pdf to show the client the designs before approval but never as final file...also I have heard from some many places that if the print house needs to open the file on a different design program the best is to send them .eps
PDF is a delivery format. As such, it is very versatile. Design comps is only one of its many uses. But PDF is not meant to be an editable format. When you deliver a PDF that was created by Illustrator and which is fully editable on the receiving end, you are really embedding in the file a full second version of the file as native AI content. Whether this AI-native content is included is controlled by you when you export the PDF.
Editing PDFs that do not have the AI-native content embedded can be very cumbersome and problematic. Again: PDF is a delivery format, not an editing format. Ideally, the printing house should not have to edit your press-ready files. It is supposed to be up to you to build them correctly. That should be your goal.
I expressly forbid printing houses from editing my delivery files. If an edit is needed, it comes back to me, and I make the edits. If a printing house chooses to edit one of my files without permission--and a problem result--they eat it; not me.
Yes, yes, if print-side minor editing (like the afore-mentioned ingredients boilerplate scenario) is part of the established workflow, that's fine; its assumedly been agreed upon as the cost-efficient workflow. But generally speaking, the kind of designer who routinely relies upon the printing house as a "safety measure" to fix his files is...well...exactly the kind of designer I would not hire.
By the way: Hearing something "from many places" (especially in online user forums) in this business is no indication of correctness or best-practice. Quite often, the most-cited advice is the bad advice. Case-in-point: The ever-cited myth that everything for print should be rasterized to 300 ppi. 300 ppi is usually needless oversampling. This is especially true in reference to mere raster effects like those controlled by Illustrator's Document Raster Effects Resolution setting. 300 ppi is almost never needed for the most common uses of such effects: blurry drop shadows, glows, etc., etc. "Fuzzy" is the very purpose of those effects. All you have to concern yourself about is the potential for visible pixelation, which is directly tied to halftone ruling.
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...what I was mention is to be able create like a table where you list the pantones use, same time to put measures guides on the artboard itself, is this possible to do in illustrator?
Again, separation names are included in the Printer Marks option of the Print Dialog. See the documentation. Depending upon your delivery format and workflow, the printing house may not even use Illustrator's printer marks; they may use those in one of their prepress programs.
But you should always check the seps before sending a press-ready file. You can do this in AI's print dialog, or in Acrobat Pro. Regardless, it's your job to make sure the project color-separates correctly. It is very common to "finish" a job thinking you have been very careful and everything is right. It is just as common to preview the seps and find an object on the wrong separation plate, or knocking out something it shouldn't, or overprinting something it should knock out.
(There's also the whole matter of trapping, which this thread has yet to mention.)
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...imagine I have a label that is a star with 200x200 px, and the artboard is white background with 300x300px,
I will add (with as much force as I can muster) my admonition to that which has already been given: when talking about actual, physical measure, forget about the web. Forget about Photoshop's rulers. Forget about pixels. A pixel is not a unit of measure. If you think it is, tell me: How big, in inches, is a pixel? I might as well ask you "how high is up?"
If you tell a printing house that the trim size of your document is 600 by 1200 pixels, he will (and should) laugh at you.
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if I print the artboard on my laser printer I get the label with the background also, so how does the print house manage to
not have the background of the artboard when they print?
If you print the artboard on your laser printer, you do not "get the background." Think about it: Do you have any white toner in your laser printer? (Think inks, not colors.)
All the above is offered in a spirit of helpfulness (and some tongue-in-cheek jest). Take it as such. Bottom line, though--and this is not meant to be the least bit insulting--unless the company you have just contracted with is a small mom & pop shop and/or has very basic labeling projects, it really sounds as if you are already in well over your head. I am certainly not saying any of this is rocket science. It isn't. A dedicated person can learn its ins-and-outs in relatively short time if that time is well spent. But an online user forum is a very error-prone, incomplete, inefficient, and therefore poor way to learn it. It doesn't sound like you have that much time to waste.
JET