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Black colour is tricky, isn't it? Look at our guide and learn how to use black colour and not to go crazy.
Everyone who ever tried to assemble a full-black outfit knows it – eventually it turns out that the colour of a turtleneck jumper is much different than the colour of your pants, even though they’re both black. Trickiness of black colour is also an excuse for marketing battles between TV manufacturers. Finally, black colour causes countless misunderstandings in the printing houses. How to avoid them? How to spot the difference between many shades of black?
Let’s start with defining black colour. The definition won’t be a huge surprise for you – basically, it’s the darkest of all the colours. In theory, it’s acquired through full absorption of the light. Such absorption may be observed for example in a dark hole, whose gravity field is so strong that nothing can escape from it, light included. But in reality, perfectly black entities almost do not exist. Therefore, we consider objects „black” when we cannot state their colour as the amount of reflected light is insufficient.
Some time ago, black colour brought many problems to the brands that produce screens and their users. In particular, many problems arose approximately 15 years ago, when people were swapping CTR screens for LCD displays. One of the reasons that made graphic designers hold on to heavy displays that hogged half of the desks was solely the way in which black colour was displayed.
A screen is a device that emits light. Recently we’ve defined the consequences of such a fact. Screens operate within RGB colour space which deals with additive synthesis, which means that all the colours are summing until pure white is reached. The best way to acquire black is therefore to simply switch off the backlight of the screen. However, in LCD displays it’s impossible, as the entire area of the screen is backlit. For this reason, we won’t ever be able to see true black – instead we’ll see a dark greyish colour.
Thankfully, the advancements of technology allowed for the LED displays that are able to display the image through partial backlight or OLED displays in which each pixel is a separate light source – this allows us to turn off single pixels.
It should be much easier when it comes to print, right? All in all, we’re operating in CMYK colour space in which black is one of the most basic colours. So all you need to do to acquire black colour is to set “K” value to a 100 percent.
Well, yes. And no.
Black colour in CMYK colour space may be acquired in several ways. As we established, CMYK is a subtractive space, in which colours are summing up until they reach black. This means that setting C, M and Y values to 100 percent should result in obtaining black. We’d strongly advise against doing so, but let’s not preempt the facts.
When it comes to print, black colour doesn’t always mean the same as well. In the print house you’ll most probably encounter two variations of black – “Regular” black as well as the so-called “Rich Black”. In this instance, we can also distinguish between two variations of black and we use them depending on the project and the type of finish.
“Regular” black is described in CMYK colour space as C = 0, M = 0, Y = 0, K = 100. Rich Black is described as C = 60, M = 60, Y = 60, K = 100. These values may vary depending on the printing device we’re using – some print houses may use values in the 40-70 range. Why aren’t all the values set to 100 percent? There are several reasons for this.
First of all, it’s just a waste of the toner – which means it’s a waste of money that at the same a bad influence on the environment. Rich Black with the values stated above will be sufficient. Also, the more paint you put on the paper, the longer it’ll take to dry it, and our printouts will be literally heavier. This might not matter as much when it comes to digital prints, but is crucial in offset printing.
Sidenote: the colour with all the CMYK values set to a 100 percent is called “Registration Black”. It is used in the graphical elements which help to situate the print in its exact place on paper or cardboard. But not always – sometimes printing house use markers with a lower density of paint.
Why do we distinguish between two shades of black? What are their functions?
“Regular” black is used to print small black elements in Full Color standard – such as objects that have thin edges and require much precision as well as sharpness. For instance, black text will be printed in this colour. Rich Black on the contrary is used to produce large black surfaces – for instance when you’re ordering a black box (if you want to be sure that it’ll be truly black, we recommend a matt foil).
Things become different when it comes to Eco and Eco White boxes. In this instance, we’re printing only in black. With regards to our printing device’s technical specs, it always comes in Rich Black. All of the projects from the Wizard will be automatically converted to this colour.
The requirements above concern mainly the projects created with the cutter as well as files saved in CMYK colour space. If you’re using RGB files in the Wizard, the required black conversion is occurring on our app’s side.
If you’re using CMYK files, all you have to do is remember the following rule:
Eco, Eco White – always Rich Black:
C = 60%
M = 60%
Y = 60%
K = 100%
Full Color – black text:
C = 0%
M = 0%
Y = 0%
K = 100%
Full Color – large, black elements – Rich Black:
C = 60%
M = 60%
Y = 60%
K = 100%
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