Colours Design

CMYK black vs RGB black: What’s the difference

There are multiple types of black to use in design. This difference is most noticeable in print and digital work. Most people use the preselected black in the colour palette in any program they are using without knowing the difference between them. If selected correctly, the black colour would look black not grey or a really dark brown.

This is something to notice in most design programs that switch from RGB to CMYK like Adobe Illustrator, Adobe InDesign or Corel Draw. Some programs would log you into the appropriate colour format if it is indicated at the beginning of the document will be seen in print or on the web.

Old printing machine printing black ink.
Old printing machine printing black ink.
Photo by Wendelin Jacober from Pexels

In print the colour palette CMYK is used therefore the black to use would be 100% black. This colour is known as 100% Black or True black. This is best to use if the print is going to be in black and white anyways or printing text in black. Using this black would prevent modelling which is a build-up of toner in one spot that would make the text hard to read. On the screen with the RGB colour setting, the black would look grey because the colour values have been converted to light values. In RGB, the values are 35 red, 31 blue and 32 green or in HEX code #231F20.

HEX code for True Black #231F20
Computer in Photoshop designing something digitally.
Computer in Photoshop designing something digitally.
Photo by Eftakher Alam on Unsplash

In web the colour palette RGB is used the values would be 0% percent. This is known as Pure black. Since RGB has the study of light wavelengths the percentage of black is zero blue, zero red and zero green wavelengths. This is the preferred black to use for a digital design like for a website but there are some drawbacks. The intensity of black can be very strong for some people and they might get eye strain when reading black text on a white background. More colours are not only available but more vibrant because it’s on-screen using light. When converting to CMYK the colour would look dark but it would be modelled. The converted code from RGB to CMYK is Cyan: 74.61%, Magenta: 67.58%, Yellow: 66.80% and Black: 89.84%.

HEX code for Pure Black #000000

Sometimes in print, the text isn’t as intense as Pure Black. Therefore, True black is mixed with the other colours cyan, magenta and yellow creating a deeper and darker colour when printing. In print, dots (or lines) make up an image on a page. The dots (or lines) that make up an image may need more dots to make up the image. A go-to standard would be 30% cyan, magenta and yellow with 100% black or 60% cyan, 40% magenta and 40% yellow with 100% black can be used to fill in the empty spaces with more dots. This is called Rich black. Rich black looks best if it’s used on a large part of the page or object like has a background or really large heading text. When the registration of the print is perfect then it should be okay. Any slight shift in colour can show the other colours underneath. The colour can create clayed results in printing and will make fine lines and small type blurred.

A print with registration marks

Another way to create modelling would be to make all of the CMYK percentages 100%. This is just a registration black. When plates are used for offset printing registration marks to make sure all the plates lined up. It usually a star and a “bull’s eye” circle near the trim marks. All printer marks will print with registration black. If the registration marks prints on one sheet it would not only be modelled, blurred and dark but on the corner of the paper. These are noticeable when the colour registration on the machine isn’t registered. It’s best to not use registration black in design just to make a deeper black colour.


Banner credit: Photo by Nayani Teixeira on Unsplash with some photoshop by Under The Moonlight

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