Creating a preflight profile is a good way to manage your files for print. You can tag resolution, color space, fonts, links, trim and bleed, etc… The following is a discussion on some of the settings you may want to consider when creating a preflight profile in Adobe InDesign. Of course you will want to check with your printer to make sure these values are appropriate or they may even have a profile they can send you.
One of the first sections you can check off is the links section (see image above). In addition to issuing a warning about missing links, you can also flag the transparency blending space. The Transparency Blending Space is the color space (RGB or CMYK) that all colors in the document must be in order to insure consistency. If you are going to use blending modes, drop shadows, bevels, gradient feathers, etc…, you need to understand how that object will interact with the other elements on the page. Type can be unintentionally rasterized if it is too close to an object with transparency (for this reason, it is a good idea to have ALL type on a separate layer and have the type layer on the top of the stacking order in the layers palette).
In Living Color
Color is always an issue and many printers no longer want “native” file formats and will only accept PDF files for print. That being said, I cannot tell you how many discussions I have had with students about color and how many complaints I have fielded about the printer ruining a project. Just remember: as much as you complain about how printers are destroying your projects, printers are laughing about your lack of print savvy!
When I teach Photoshop, I tell my students to always work in RGB mode, even if the final destination is print! Why? CMYK and Photoshop layers are not always on good terms; you won’t be able to use your plastic wrap filter because not all of your adjustment layers are available and none of your digital photography profiles will match your color space. I teach my students to work in RGB and save their RGB file and maintain their layers when they are done. Then flatten a version of that file and convert to CMYK. The result is a file in RGB space with layers intact that can be edited if need be and a flattened version in CMYK that can be placed in InDesign. Why go to all this trouble? If you convert to CMYK in Photoshop you have a better color engine and you won’t be surprised. Also, if you convert the flattened file you will marry all of your composites; blending modes change from RGB to CMYK, so it’s best to “bake” the look into a flattened file. Finally, if you start with RGB, with its larger color gamut, you will have a more vibrant image for your website (because of course you are going to use this piece for print and web).
Spot colors are a different story. You will notice that my profile only allows for one spot color (see image above). Your project may have more but I have seen files with 25 spot colors (not intentionally). Be aware that when you specify a Pantone color for a swatch you can choose between spot or process. Process, for the most part, is the way to go.
I also have warnings for overprinting and registration. NEVER use registration in a project. It is there to be used by the software to print the Printer’s Marks and is mixed from 100% of CMYK. No paper can hold 400% ink but on a tiny registration mark it does the trick. If you need a “rich” black, ask your printer. An example would be C 70% M 40% Y 30% K 100% and this would only be used on large background areas and never for type (unless it’s huge).
Overprinting is tricky. By default, when you place one color on top of another, the top color “knocks out” the bottom color where they overlap. If you apply a blending mode like multiply, you are setting the attributes of an object to overprint and are telling InDesign to let these objects blend. All ink is somewhat translucent; so blue over yellow will produce green. If you do this it is important to turn on Overprint Preview from the view menu. Lastly, “white” or “paper” is not a color in offset printing. so be careful on how you use it. If your paper is not white, the swatches assigned to paper will not be white either.