Transcript
Océ ⏐ ONYX Support Information Bulletin Number: 27 • Issued by: DGS S & S, Vancouver • June 2, 2014
Creating and Using ONYX Profiles Containing White Ink This document provides guidelines on creating and using ONYX profiles containing white ink. Some sections of this document are only applicable to ONYX 11, which contains new features to set spot data ink restrictions and linearization based on ink volume. Two challenges when creating and using ONYX profiles containing white ink are: 1) how to set white ink restrictions to improve smoothness, and 2) how to linearize white ink when printing gradients or tints < 100%. This information is targeted towards to those who are already familiar with creating ONYX profiles on the Océ Arizona printers. Important topics are: • • •
For White Spot data, use the “Absolute Ink Volume” in the ink restrictions step when creating an ONYX profile. Restrict the amount of white spot ink to improve the smoothness and reduce the “edge of swath banding” For printer flood using white ink, using a level 4 or 5 drop size (instead of the default level 6) will improve the smoothness and reduce the “edge of swath banding”
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Spot Color Setup for Viewing Spot Data in the ONYX Job Editor In this example a CMYKSS ink configuration ONYX profile is created. A color and opacity is defined for each spot color. Opacity of 50% is selected. This selection has no effect on the print result, but only on the preview in the Job Editor.
Figure 1: Setting Spot Color Opacity
When 100% opacity is used, the white ink layer will block the view on the image. This makes it harder to see design mistakes like forgetting to enable the “fill overprint” option. The screenshot on the left shows an opacity of 100%, while the screenshot on the right shows an opacity of 50%.
Figure 2: Viewing 100% and 50% Spot Opacity Settings in ONYX job editor
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Setting Application Dependent Mode Options The Océ Arizona printers can print up to 3 layers ink during the same pass. It is possible to change the layer setting in the printer settings in Rip-Queue for a particular job, but it is recommended to setup some application dependent layer settings when creating an ONYX profile or Quickset. Since the optimal amount of ink depends on the application it is convenient to define different print modes that are application dependent: printing on black or transparent backlit or day/night media. When printing white flood area’s it is often convenient to have the printer flood the white ink using the extents of the data bounding box. However, there are situations where it is preferred to flood white ink using spot white ink data instead, e.g., flooding a non-rectangular area. Here some examples of how to configure white spot data for two different applications: printing on black media and printing day/night on transparent media. The layer settings on black media are set to 2 layers of white ink and a single layer of CMYK. The 2 layers of white will give a good coverage on a black media.
Figure 3: Selecting Mode Options
Figure 4: Selecting Ink Layers to Print on Black Media
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For printing on transparent media, the “day/night” application is common. It will show a nice image when viewed in day light or when backlit at night.
Figure 5: Selecting Ink Layers to Print on Transparent Media for Day/Night Application
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Restricting White Ink White ink can be restricted within ONYX profiles by either setting spot data ink restrictions or controlling the drop level used for print floods. Either approach can be used to limit the volume of white ink to improve smoothness and reduce “edge of swath of banding”. Spot Data Ink Restrictions When creating ONYX profiles ink restrictions are automatically determined based on the measurement of swatches using a spectrophotometer. For White ink and Varnish, this is not possible. In previous versions of Onyx, the ink restrictions for these spot colors were always based on the measurements of the black ink (K). In version 11, there are options to set the ink restrictions based on ink volume and remove the limitations based on the black ink. This screenshot shows the ink restrictions like they are done before version 11:
Figure 6: White Ink Restrictions Prior to ONYX 11 For the new ONYX 11 profiles the maximum White ink is made available and the linear values are used for printing White Ink spot data.
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Figure 7: ONYX 11 - White Ink Restrictions using Absolute Volume Set to 1.0 Printing with these white ink restrictions will use the largest drop size (level 6) when printing a 100% tint flood area using spot white data. (FYI, for white ink level 6 is a 180% double-strike of level 5 drops, so it is almost twice the volume of ink compared to level 5 drops). This would likely result in an “edge of swath” banding for the white ink. To limit banding, it is better to use drop size levels 4 and 5. This can be accomplished by restricting spot white ink to 75%. For this reason a profile called “day/night” is created.
Figure 8: ONYX 11 – White Ink Restricted to 0.75 For versions of ONYX prior to version 11 you can restrict spot white ink by using a data tint value of less than 100% for white ink spot data floods. To find optimal tint value it is suggested to make 85%-100% tint boxes in 1% increments and print using spot white ink. Then select the optimal tint % that produces the desired opacity with minimal “edge of swath” banding. Printer Flood Ink Restrictions When the “day/night” application is printed with a flood channel White, the latest Onyx drivers have the option to select the drop level size. A level 4 or 5 drop size often gives a better result than the level 6 drop size.
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For jobs using 2 layers of white flood ink, the best results are achieved when one channel is set to use level 4 drops and the other white flood channel to level 5 drops.
Figure 9: Printer Flood Fill Using Drop Level 5
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Optimizing White Ink Spot Data Linearization When working with white ink gradients or tints < 100% the white ink linearization curve can be tweaked to produce smoother transitions through the tonal range. If White ink is not restricted and level 6 drops are used and since the level 6 drop level is almost twice the size of the level 5 drop size, the curve between 50%-100% input has to be pushed down. There is no easy way of changing the linearization of the white ink, since it based on the linearization the black ink. The measurement values are shared for both channels. Any change would affect also both channels. To show the linearization of White Ink is based on the measurement values of Black ink:
Figure 10: White Ink Linearization Based On Black Ink Values To change the linearization curve, the target values are changed for Spot 1.
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The original target values:
Figure 11: Select Spot 1 Values For example, to change the output of the 40% input value to the 60% value, the target density of 40% will have to be changed to 0.660 for 40% The screenshots below show the starting point (straight curve) and the end result of the linearization curve.
Figure 12: Modified Linearization Curve The start point (almost a straight line) is typical when using the automatic restrictions method. During this step, a compensation curve is calculated to give more accurate readings for the linearization step.
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Printing White Ink Using Print Modes Other Than Quality-Layered Print modes other than Quality-Layered mode can also be used to print only white ink, or areas of white ink in an image as long as the ONYX media profile has been made with a CMYKS or CMYKSS ink configuration with spot color(s) defined.
Some print modes print more uniform white ink than others. For Arizona 550 and 600 series printers Quality Smooth print mode prints the most uniform white ink compared to other print modes. Sometimes productivity can be increased by printing white ink in a faster print mode, e.g. Production Mode. When printing white ink using non Quality-Layered print mode it is not recommended to print white ink in the same gantry pass and in the same area of an image as CMYK inks. The white ink does not mix well with the other ink colors.
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