Getting printed output that matches what you see on screen is a bugbear of most graphic designers and digital artists, so here's the colour geeks at Colour Confidence's guide to producing perfect prints.
Before we begin, it almost goes without saying that a precisely calibrated? monitor is the first step towards ensuring that the images you are preparing? for print are as accurate as possible. A monitor calibrator, such as Pantone's ColorMunki or DataColor's Spyder3Elite, is a must for this.
Right, let’s get started. The basis of these tips is that the final artwork is to be supplied in CMYK format for a conventional four-colour CMYK print process.
Tip 1: Set your preferences
In the Adobe Colour Preferences (Edit > Color Settings) in Photoshop, Illustrator and InDesign, set your RGB working colour space to Adobe RGB and the CMYK working colour space to Coated FOGRA39.
Selecting the ‘Europe Prepress 3’ preset in CS5 apps will pre-configure these accordingly. If you use CS4, select ‘Europe Prepress 2’. This which will configure based on the older Coated FOGRA27 CMYK profile, which should be sufficient. This can also be replaced with Coated FOGRA39 by manually selecting it if you have access to it.
One trick to ensure your colour spaces are matched -- and save a bit of time -- is to set this in Adobe Bridge. Select Edit > Creative Suite Colour Settings, and you can synchronise all your Adobe applications so that they use the same colour settings.
Tips for working in Photoshop
Tip 2: Always select ‘Preserve Embedded Profiles’
If you receive an image that uses the sRGB colour space (rather than Adobe RGB) is received, leave it in sRGB mode until the point of converting to CMYK -- unless you need the scope to increase the saturation of colours from the sRGB to Adobe RGB range. In this case, converting the image to Adobe RGB will be required.
Tip 3: Stay in RGB as long as possible
When preparing images in Photoshop, it's always best to stay in RGB mode whilst colour-correcting the image. To ensure the image remains optimised during the CMYK print process, the last step should be conversion to the appropriate CMYK profile.
Tip 4: Proof before converting
To avoid the need to make colour adjustments after the image has been converted to CMYK, first ensure your proof settings are correct (View > Proof Setup > Working CMYK). To turn this on, select View > Proof Colors (or Cmd/Ctrl + K) to simulate the outcome of converting to CMYK. Remember to select this again to turn it off afterwards.
Two useful options to your proof settings can be found under View > Proof Setup > Custom. ‘Simulate Paper Color’ and 'Simulate Black Ink’ options will reduce the contrast range of your proof view to that of ink on paper. Turning this off will extend the contrast range to that of the monitor. This is helpful when working on image detail.
As your eyes adjust to changes in lighting conditions, both are acceptable working methods, but if you want to be able to hold a print up along side the monitor and get an good match, then these options should be selected.
Tip 5: Keep an RGB copy
When your image has been colour corrected, save a master copy in RGB so -- if needed -- you can modify it later with the maximum colour information. Then proceed to scale it to the required size, apply ‘Un-sharp Masking’ and then convert to CMYK, saving this as a new image file.
Tips for working in Illustrator
Tip 6: CMYK matching
If you need to include logos and corporate graphics matched to specific CMYK values, work in CMYK mode from the start. When you select other CMYK colours for other elements alongside them, ensure that the combined percentage of CMYK does not exceed the maximum allowed by the print process the artwork is intended for. The Coated FOGRA39 profile sets this limit at 330%.
Tip 7: RGB first, CMYK last
Another approach is to create your most of your design or artwork in the Adobe RGB colour space, using placeholders for elements with specified CMYK elements. When your artwork is complete, convert it to CMYK and drop in your specified elements,
Tip 8: Proof it
If you're working in RGB, Illustrator has the same Proof Colors and Proof Setup functions as Photoshop (see Tip 4).
Tips for working in InDesign
A combination of RGB and CMYK image files and components can be combined into a single document. If you select Proof Colours (View > Proof Colors), InDesign will simulate the appearance of RGB colours and images after they have been converted to CMYK. These RGB elements can be converted to CMYK at the point of printing or output to PDF.
In an ideal world, keeping all files in RGB until printing/output is recommended, but generally there are some components that require specification in terms of CMYK, such as a tinted panel of 50% cyan. This is because, if an equivalent were to be specified in terms of RGB, it is unlikely that the resultant colour would be a pure 50% cyan without a small unsightly component of magenta, yellow or black.