Verifying the Correct Color Space of Your One and Two-Color PDF Files

CMYKColor in a PDF file intended to print one or two-color has become the number one barrier to efficiently moving files from pre-flight into production.  When a printer encounters this problem, production grinds to a halt.  Valuable time is spent determining whether or not files must be redone.  By communicating the following information to your text file builders who can follow these instructions to verify the correct color space prior to submitting files to your printer, publishers and content creators can avoid these hiccups.

There are primarily two reasons why a PDF designed to print in one or two-color may inadvertently include additional colors.

Category #1:

Color elements such as RGB, CMYK or even Pantone have been created or placed in the native Quark or InDesign document.  For a design meant to have two colors, there may have been colors other than the two intended added to the file.

One-color

When we receive and process one-color PDF files that fall into this category, gray scaling will take place.  Inferior gray conversions are fairly infrequent however, when they exist, they are subtle and hard to catch.  Removing the color from your one-color native files can help you avoid this problem.  If you choose to send your printer PDF files containing color elements and you want them gray scaled, keep in mind that you may have to accept your printer’s RIP default grayscale conversion.  Letting your printer know ahead of time how you would like your documents gray scaled can save time in the production process.

Two-color

When a printer receives two-color files that fall into this category it is not uncommon for them to ask you to make appropriate changes and re-save your files as a PDF.  Many printers will re-work your files for you (including Edwards Brothers Malloy) however be sure and let them know that you wish to do so.  Otherwise you may be surprised down the road or forced to accept the printer’s default options.

Category #2:

The method used to save native files to PDF can cause correctly built one or two-color elements to “save” in the RGB or CMYK color space.  To avoid problems like these, you should save your files using your printer’s RIP-ready file guidelines.  Many printers have specific recommendations depending on how their workflow is designed.  For example when customers send files to our prepress department, we recommend saving text documents using our Saving text documents to RIP-ready files guidelines.

Another common misconception is that widely used programs like Microsoft Word will save black only files as black.  This is not the case and should not be relied upon.  PDF files made from PC MS Word will always “save” in the RGB color space and the PDF file will always have to be gray scaled before plates can be made.  This is true for any printer that you may send native Word files to.  Remember that if you do not gray scale a file yourself, be prepared to except your printer’s default settings and be sure to discuss this with them before moving forward.

Two Color Files

The same problems that occur with one-color files can also occur with two-color text files. In addition to RGB and CMYK color space issues mentioned above, two color files have the added complexity of requiring the second color to be consistently identified throughout the file. An example of this problem would be to identify Pantone 250 multiple ways in the same file: as Pantone 250 CVU and/or Pantone 250C, in addition to Pantone 250.  In this example, the logic within Prinergy (software used in our workflow) would identify CVU and C as the ‘same’ and all of the Pantone 250 elements would end up on the same plate.  However, to avoid potential problems, whenever possible, this sort of complexity should be removed from your files.

The following are instructions for using Acrobat Pro 7* to check your PDF files intended to print one or two-color.  This method of file checking is the most reliable way of identifying inappropriate colors in a PDF file.  Note that the screen shot below is from Acrobat Pro 7.  These tools are available using Acrobat Pro 6 and 8 also.  Slightly different screens and instructions will apply.  These tools are not available using standard Acrobat or Acrobat Reader.

Using Acrobat Pro 7 launch your PDF file:

  • In the “Advanced” tab select “Output Preview”
  • In “Simulation Profile” choose “U.S. Web Coated (SWOP) v2”
  • In “Preview” choose “Separations”
  • In “Separations” deselect “Black” (or the single Pantone color intended) from the list of plates
  • If text is two-color, deselect both colors that are to print (see note “For two-color files”)
  • Carefully cursor through each entire page in your PDF document.  If the PDF is correctly built as a one or two-color file, this view of your pages will show them all as being blank.  If in this view, you see an element on a page, it is because that element has an inappropriate color designation.

Color Space in Adobe 7

If you ever have questions about how to build your files for correct submission to Edwards Brothers Malloy, you can always contact a customer service representative for help.  They have years of knowledge related to file preparation and can help make the process very smooth.

 

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