CD DVD Disc Design - To print on a white flood or not?

When creating the design for your CD/DVD disc, there can be confusion about the need for adding a "white flood" (aka: white back-print). In the vast majority of cases a white flood is indeed used, but here's an explanation that should help you decide what's best for your design.

The colour of the material affects the colour of the print

Printing onto a white background is the standard for most types of printing applications because 'white' is a neutral colour that doesn't affect the colours being printed on top of it.

A simple way to illustrate this would be to print your design onto a white sheet of paper, and then print the same design onto a coloured piece of paper. You should see a difference in the printed result, because the ink colours are influenced by the colour of the material it's printed onto.

Based on this, printing directly onto the aluminum colour of CD/DVD discs without a white flood can affect the appearance of the print. In addition, if you require the colour "white" in your CMYK design it's normally provided through the use of the white flood/back-print.
 

The example on the left is printed on a white -finished CDR inkjet printable disc. The colours are richer, the light colours are brighter, and there's more contrast between the light and dark colours.  The example on the right is printed on a silver -finished CDR inkjet printable disc. The print is slightly darker and the colours are more dull in appearance.

CMYK inks are translucent

A reason why a white flood (or white back-print) improves the visual appearance of the print is because of the type of ink being used. Commercial printing is commonly done using the CMYK colour mode:

  • C = Cyan

  • M = Magenta

  • Y = Yellow

  • K = Black

Because CMYK inks are printed on top of each other they cannot be opaque - instead they have to be translucent. This translucency means the colour of the material underneath the print is partially visible through the ink. Typically, the colour of the material should be more noticeable through light print colours than through dark colours. 

Sometimes the results can be subtle enough where the design isn't negatively affected, and then other times the results can be very obvious... it all depends on the design.
 

[http://www.predisc.com/footer2.htm]