When designing artwork for badges and other printed products you should generally be working with CMYK colour. CMYK stands for Cyan, Magenta, Yellow and blacK. These are the colours of ink used in most digital printers and all other colours are made up by combining these along with the white of the paper.
The other common colour system is RGB (red, green and blue). This colour system is using for images to be displayed on screen only as screens use the colours in combination to display the full range of colours seen on screen. Artwork for print should not be designed using RGB colour as it will have to converted to CMYK for printing and this can cause colour changes.
A CMYK colour value consists of a percentage value for each of the colours. A common mistake when trying to produce a dark black using CMYK printing is to enter a vale of 0, 0, 0, 100. This would mean the 'black' is printed using the maximum amount of black ink and no other colour. This seems logical however the result will be a disappointing dark grey.
In order to achieve a full bodied, dark black it is necessary to use all four in combination. For a dark black you should use a CMYK value of 60, 40, 40, 100.
The image below has been converted from CMYK to RGB for display online but illustrates the difference between printing with just black ink and printing black using all four colours of ink.
Be sure to use the CMYK value 60, 40, 40, 100 when using black in your badge designs.