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Subtractive Colour.
This section contains some background material on the colour process used in printing. The colours (Yellow, Magenta,
and Cyan) used in dye sublimation use a subtractive colour process. Subtractive colour starts with an object (often a
substrate such as paper or plastic) that reflects light and uses colourants (such as pigments or dyes) to subtract portions
of the white light illuminating an object to produce other colours.
If an object reflects all the white light back to the viewer, it appears white. If an object absorbs (subtracts) all the light
illuminating it, no light is reflected back to the viewer, it appears black. It is the subtractive process that allows everyday
objects around us to show colour. Colour paintings, colour photography and all colour printing processes use the
subtractive process to reproduce colour. In these cases, the reflective substrate is canvas (paintings) or paper/plastic
(photographs, prints), which is usually white. Colour monitors, television‟s, projectors etc. use the additive process.
Subtractive colour process (YMC)
In theory, overprinting all three colours produces black. In reality, a dark grey is produced, so black is used as a fourth
printing ink, hence the „K‟ (for monochrome) in YMCK.
The K Resin layer allows very sharp defined black text, barcodes etc. to be added.
Printing.
Due to the ceramic print head being rigid the quality of the Card surface is extremely important if high quality images are
to be produced. Cards should be selected which are cut cleanly at the edges and have perfectly flat surfaces.
There are various Card manufacturers and several different types of PVC Card. Each of these will accept colour in
differing amounts using the same Print Head temperature. This is due to the PVC being used and the manufacturing
process.
When printing a full colour Card, the print head will get progressively hotter as it operates. This is compensated for in the
printer Firmware but it may affect how evenly some Card designs print.
Dust and debris on the Card surface will cause small white blemishes to appear in the image so keeping the Cards and
tacky rollers clean is imperative.
The Printer creates the Card by placing layers of dye onto the Card in the following sequence:
Yellow:
(Y)
Magenta:
(M)
Cyan:
(C)
Black:
(K) or Resin black
Clear:
(O) or Overcoat.
The Overcoat layer acts as a protective film against wear and fading and can also carry a secure image, which cannot be
photocopied (Ultra Secure).
Colours appearing on the monitor will not always be exactly the same as those printed by a Printer; this can be due to
various issues such as in transmitted light from the monitor colours can look different than viewing reflected light from the
Card. All monitors will show the same image slightly differently. Different plastic surfaces will give differing results and
the Dye-Film could vary slightly from batch to batch. For these reasons, the Printer Driver has been designed to allow the
user to adjust various aspects of the colour output.
Ultra Electronics Card Systems
Rio Pro Maintenance Manual
- 7 -
Additive colour process (RGB)
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