The Multicolor Mode

Multicolor Mode determines how colors will be built up in individual separations. The Multicolor Mode is available in printer profiling when multicolor measurement data has been loaded (New Printer Profile > Customize > Black Generation) or in DeviceLink profiling when a multicolor target profile has been loaded (Device link > Customize > Black Generation).

In CoPrA, the first three channels represent primary colors (usually CMY). They should form a sound color space (gamut) and should also be able to create a gray axis. The fourth channel should be black if a separation with UCR/GCR is desired. If black is absent in the multicolor measurement data while automatic Black Calculation is selected, it will be recognized by CoPrA and the separation will not be generated. Black separation is disabled if the value for Max. Black in the Black Point and TAC setting is 0%. Additional spot color channels (e.g. Orange, Green or Violet in a CMYK-OGV 7 color data set) are regarded as color space expanding colors. The Multicolor Mode determines how color space expanding colors are factored in together with primary colors.

Note: A multicolor license is required to use multicolor features.

  • By use of the mode Strong as much spot color as possible will be applied. Accordingly, less primaries will be used in the highly saturated color areas. This results in a greater use of color space expanding spot colors and therefore in highly saturated colors in the printout.
  • The default setting Smooth should be maintained if a particularly smooth and harmonious separation with saturated colors is required.
    Note
    : The two modes Smooth and Strong are similar in CoPrA 4.2 but Smooth uses less color space expanding spot color channels.
  • There are two new modes available in CoPrA 4.2: Smooth – with special colors and Strong – with special colors. They are designed for applications in industrial printing, such as ceramic printing, in which the main colors are supplemented by additional light (e.g. Pink) or dark (e.g. Brown) color space expanding colors. The two new modes are an enhancement of the existing modes Smooth and Strong, however, they also use additional colors that are not commonly used. For example, the additional color pink is used with a darker magenta in magenta gradations. Here, pink is used in light areas while magenta is used in dark areas.

Notes:

  1. The gray balance of the two new modes shows additional channels as bright or dark colors are incorporated into the gradations and gray balance curves.
  2. These two modes also support light inks in profiling, such as bright and dark magenta. In principle bright and dark colors should be processed in the printer or RIP (Raster Image Processor), as they require particularly large test charts for profiling.
  3. It is also possible to combine light gray with black which can mask noticeable artifacts in the highlights, which can be seen in flex printing. However, appropriate test charts have to be used.
  •  Generate separations with sparse inks is of interest for the packaging market as color separations are created in such a way that a certain hue uses as much as possible of a related spot color and very little or no primary colors. For example, in order to create a red hue as much as possible of a reddish spot color is used but very little to no magenta or yellow. A maximum of two or three colors are used for each color segment and, therefore, this mode is practical to save process colors. However, black generation cannot be controlled and is based on the mode MaxK.
    Note
    : In contrast to the modes Smooth, Strong and Use CMYK only, the mode Generate separations with sparse inks does not allow regulation of the Black Generation. Accordingly, these settings are grayed out.
  •  Selecting the method Use CMYK only results in a multicolor printer or DeviceLink profile that creates the desired number of channels (e.g. 7 channels) but is only composed of CMYK. The color space expanding spot color channels are not used for the separation, but are used for the simulation of colors.
    Notes
    : In package printing there is sometimes a request for images and vectors composed of CMYK to be generated with only minimal changes to CMYK values and without spot colors – despite conversion into a multicolor space. In this case, only spot colors which are present as DeviceN in the PDF should be converted into the large multicolor space. Such a workflow is possible in two easy steps: (1) Creation of a separation-preserving CMYK-to-Multicolor DeviceLink profile in CoPrA using the multicolor method Use CMYK only. (2) Spot color conversion of the PDF using ColorLogic’s color server ZePrA.
    In CoPrA all options of Black Generation (i.e. the entire tab) depend on black being present in the measurement data. This also applies for Exceptions in DeviceLink profiling. All Exceptions concerning black (Gray, Black, Duplex, Triplex, Black overprint) use black as fourth channel, therefore, black must be present in the measurement data or ICC profiles as fourth channel.
    If black is not present in your measurement data as fourth channel, this channel will be treated as if it were the black channel. As an example, if blue is present as fourth channel, then all options in the tab Black Generation and also the options in the tab Exceptions will still treat the fourth – now blue – channel as black channel. In this situation, spot colors can be used for the calculation of the gray balance and the black point, which may not be desirable.
  • Preserve color properties is only available for multicolor-to-multicolor DeviceLink profiles which comprise the same number of channels for source and target profiles. This mode allows to set Exceptions for all multicolor channels rather than CMYK portions only.

    Note
    : Exceptions for Primaries effect all channels when using the Preserve color properties mode. The exceptions for Secondaries keeps all two-color combinations pure, not only those with CMY portions.
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