The basics of printing has changed very little since my Great-Grandfather’s day, but of course the technology afforded to us in the 21st century has made the colours more accurate, the speed of printing faster, and almost total automation possible.
At LRP, we use what is called “offset printing” for our mainline stationery collection. Offset printing is when our images (made up of millions of tiny dots) on metal plates are transferred (“offset”) to rubber blankets and then on to paper. Personally, I find the process completely fascinating- bear with me!
Did you know that every colour we can see is made up of 4 basic colours: CMYK (Cyan, Magenta, Yellow and Black)? The proportion of these colours to each other determine the colour we can see on the paper. They are printed one colour at a time, one dot on top of the other.
Our cards are printed on a German 4-colour press where the image is printed by running the paper once through 4 sets of metal plates- one for each colour. Surprisingly, there is no hard rule on the sequence, though printing black last is recommended.
The image that we see on the screen is RGB (Red, Green and Blue- only 3 colours as there is no black) whereas ink on paper is CMYK, so it is totally different and cannot be exactly replicated. Therefore, at “press check”, we need to subjectively approve a different colour image to what we have been seeing by looking at the image on paper as it comes “hot off the press”!
For example, we may want to adjust the blue background of our Star Ferry birthday card lighter/darker. Adjusting blue will affect green (which is yellow + blue) so the green changes lighter/darker as well. Our job is to come out a compromising effect which we are happy with.
Our presses run around 10,000 sheets/hour, which is about 2-3 sheets per second. It takes time for both the press and the ink to warm up before we take a sheet out to “check”. Thus we would usually allow 250 sheets extra for this as ‘wastage”. The wasted sheets are flipped and “re-used” for the next round of checking. Cool, huh? ?