The numbers and letters on your Copic Markers represent classifications within the Copic Colour System (colour family, saturation & brightness). These classifications help you pick colours that will work well together.
Use the classifications of the colour family, saturation and brightness to choose colours that naturally blend together by following these rules:
1. Match the colour letters by keeping the colour family the same
2. Match the colour saturation number keeping the tone the same
3. Pick the colour brightness numbers within 2 or 3 digits from each other
Example: The below image uses YR04, YR07 and YR09. Have a look to see how easily these colours blend together.
Example: The below image uses YR00, YR16 and YR21. These colours are from the same colour family but have different saturation numbers therefore the tones in the colours are different. They also have different colour brightness and when trying to blend these colours you can clearly see when one colour ends and the other starts.
For smooth blending always try to purchase markers in groups of two or three, with varying degrees of brightness. For example B00, B02 and B04
Please note: Printed Colours VS. Actual Colours
Printed colour charts are for reference only. To know what your Copic colours really look like you will need to create an actual colour swatch. The Copic swatch book is available from your local Copic Supplier. This is also a great way to keep track of what Copic colours you have in your collection.