When there are so many mediums to communicate in these days; online and offline, print, web, video, portable devices, fabrics, glossy and matt papers.... it's hardly surprising. Here we will try to simplify the mystery by focusing on two common areas: RGB and CMYK, the first is found on screen and the latter is used in print. It is important to obtain the advice of a design agency that work in these mediums and understand the different measurements and colour formats that work for the end product. Plus, more importantly, how to ensure accurate colour matching across several outputs.
So, let's start with how colour is seen and reproduced. The circle of colour here is seen by the human eye in what's known as a Gamut. This image shows four shaped areas where the boundaries of that colour capability are, starting with the largest and "purest" working into the smallest and "dirtiest" gamut. Anything outside the boundary cannot be reproduced in that particular colour space.
Visible - What your eye sees and your brain interprets.
RGB - What a monitor, TV or other "backlit" screen generally shows you (Red Green Blue mixed).
Pantone - The measurable system we use in print and other media to dictate exact colour matching which covers special spot colours and metallics (though they are not shown here).
CMYK - The traditional four colour process used in most print, made up of Cyan, Magenta, Yellow and Black (known as K). Also, you'll recognise these base colours in your everyday inkjet printers and laser copiers when you open the lid. These CMYK "percentages" get mixed according to the saved info in the file itself so you end up with a "mix".
Basically, in production, if you imagine your media in the four colour printed form being the "dirtiest" and the online/web form being the "purest" this will help explain the next bit. If you happen to have a bright/vibrant logo or image on a website or on screen in a document and this is transferred to paper, you will notice it loses some of its vibrancy, especially any bright pinks, greens or oranges on screen (Orange is notoriously difficult to match in a CMYK environment). This is because the smaller gamut of CMYK is trying to emulate the wider gamut of RGB and will be missing a great chunk of that gamut where the bright colours exist.
Everything has an opposite. Additive RGB is used in video, TV broadcast, web etc, anywhere there is a screen or monitor, which has three colour channels, mixed on screen in pixels, to which light is "added" behind to create a vibrant image. Additive colour mixing: Adding red to green yields yellow; adding all three colours together yields white. Subtractive CMYK is the common gamut found on paper and most things printed. This is called "Subtractive" colour because as you can see it works in the opposite way to the RGB model. Mixing the "apparently pure" CMY to 'build' a colour image, then the black (K) is added last for deep shades and definition. These colours are laid down in tiny dots at varying angles to "visibly mix" the colour when seen at the correct viewing distance (if you're curious, just hold a magnifier over a magazine or next time you walk past a billboard take a closer look and you'll see the dots close up).
There are too many measuring methods within print to get into here but Pantone is the designer's or printer's de-facto way of finding a highly efficient way of handling colour and matching across different substrates. With RGB there's not so many issues but it can still be a minefield if you're not a web designer or a video effects editor. (Other trades use RAL or BS to match paints for instance.) In reproducing colour it is essential to know which gamut you are working in and then utilise the correct measurement of that range; web safe RGB, CMYK for process print or Pantone Spot for special one-off colours. Then there's the medium/substrate onto which that colour is projected or printed (now it gets complex and I'll maybe save that one for another day).
For a common example of where it sometimes goes wrong, all Microsoft products work within an RGB gamut and as such work fine on screen but don't transfer their bright colours at all into a printed form. This is a most common misconception with some of our clients, working in a general office environment, supplying the odd graphic from software like Powerpoint or Word and wondering where their bright image has gone. It will never reproduce what they expect in print and so we have to convert these files prior to production and try to colour correct as much as possible to bring the vibrancy back somewhat. The same goes for any digital image found online or from an image bank, these are always stored online in three channels (RGB) as opposed to four (CMYK) as it avoids the wasted file size in that extra channel.
This is why a designer or media pro uses the correct software (InDesign, Quark, Photoshop etc.) as they carry the up to date colour book info needed and usually a calibrated monitor that "emulates" the correct CMYK or Pantone On Screen so they will achieve good consistency. They would take a brief from the client, then try to ease through this process without too much fuss or confusion for the client. It tends to get more confusing with the introduction of unlimited substrate variants and then how to deal with that colour management across all of them. Then there's the unlimited amount of substrates that can be printed onto with Litho, Digital, UV, LED, Dye Sublimation and Screen Print processes.
Maybe to some this doesn't seem that important but we believe colour management is a highly important practice in all design projects and processes - after all, would you react well if your bright orange company logo appeared great on screen but as a rusty brown in your print?
Hopefully this has given you a short insight into how it works and has not confused you too much. At least here in the two most common mediums this illustrates why it does actually pay to create graphics in the correct way at the outset by investing in that professional knowledge. Vivid Pixel can assist you with some free advice at the outset of any project and are happy to perform tests and samples on any cross media work we are commissioned for.