Understanding Colour Profiles
A little bit about the three types of colour profiles.
1.RGB Colour Profile
The RGB colour profile is used when designing for online ads and websites.
RGB colours have the widest range of colour possibilities (widest colour gamut) and look brilliant when lit up on a screen.
RGB uses base colours of Red, Green, and Blue. Typically a colour is defined by assigning a value between 0 and 255 for each base colour. For example, a navy blue colour would be: R=43 G=54 B=110. RGB colours are also often expressed as hexadecimal codes preceded by a hashtag. For example, a forest green would be expressed like this: #376839.
2.CYMK Colour Profile (also referred to as 4 colour process or process printing)
Designing something for print requires a CMYK colour profile. CMYK is used for digital and offset printing. CMYK has a more limited colour range than RGB. CMYK uses the base colours of Cyan, Magenta, Yellow, and Key (or Black). These colours are usually expressed as percentages of each base colour. For example a deep plum colour would be expressed like this: C=74 M=89 Y=27 K=13.
This four colour combination prints vivid rich colours and achieves the deepest black.
3.Pantone Colour Profile (PMS)
The Pantone Profile is a proprietary matching system. It’s the industry standard for defining a spot colour as opposed to mixed CMYK colours.
PMS is a good way to define and preserve specific colours to maintain brand integrity (i.e.: a logo or letterhead with only 1 or a few solid colours). The colour range of Pantone inks is far wider than the standard CMYK gamut. It can also include specialty inks such as metallic or fluorescent colours.
The Pantone Colour Bridge Book allows you to print 4 colour process (CMYK) in specific PMS colours. Though this is not an exact science, it is the best way to select specific colours.
Choosing the Correct Colour Profile
Getting a perfect colour match in offset printing can be challenging because many of the colours in RGB format aren’t available in CMYK (ie: bright blues and oranges).
Since the colour range for CMYK printing is more limited than with RGB or PMS printing, your designer should provide samples from the PMS Colour Bridge Book.
The bridge book shows the PMS colour alongside how that colour would look when converted to CMYK (there is a bridge book for coated paper and uncoated paper). Your designer plugs those CMYK values into the file. There is always a slight variance in CMYK offset printing. But this is still the best way to achieve the closest desired results.
Choosing “correct” colours is not a simple process.
The most important thing to remember about colour is that what you see on screen may be challenging to reproduce in print. Using the Pantone Colour Bridge Book, a good designer can achieve your desired colour as close as possible in print. But it’s not possible to get 100% accuracy.
Colour matching is NOT an exact science but we try to get as close as possible by calibrating colours between our proofers and offset presses.
If your files are saved correctly, the printed results should match your vision. But keep in mind…even with this attention to detail and best practices, Calibration and Colour Management are challenging, and only work “so well”.
Check Your Black
Use Standard Black for small text (12 pt. and smaller) and fine lines.
Use Rich Black for large areas of solid black. It’s a combination of the 4 process colours CMYK (ideally 30% each of CMY and 100% K). This creates a rich looking black when printed.
