"Device Colors/DeviceLink" tab
In this tab, you set how device-dependent colors will be handled for conversion to the device-independent profile connection space.
"Device dependent Colors" group
In device-dependent color spaces, no ICC profiles are assigned to the colors of the images and graphics. In other words, these images and graphics are available exactly as they were, when they came from the image-producing device (digital camera, scanner) without any gamut mapping. The device-dependent color spaces are: DeviceCMYK, DeviceRGB and DeviceGray ICC profiles are assigned to these color spaces through color management. In this process, each object (images, graphics) is transformed to the device-independent CIEL*a*b* profile connection space. You can assign these profiles and set other options in "Device-dependent Colors".
"ICC/DeviceLink Profile" boxes
You can set an ICC profile for each of the object types RGB images/RGB graphics, CMYK images/CMYK graphics and grayscale images/grayscale graphics.
The following ICC profile types exist:
•Input profiles, for e.g. scanners and digital cameras
•Display profiles, for e.g. monitors
•Output profiles for e.g. color printers, CTP devices (offset printing), digital presses
•Additional profile formats, e.g. Device Link profiles, color space conversion profiles, etc.
These ICC profiles determine how color management transforms each object to the device-independent L*a*b* color space (exception: Device Link profiles). From the viewpoint of the Prinect Manager, these profiles determine the input behavior of color management, even if the respective profiles were already generated for the output devices. The press profile ("Color Management" tab) matches the data to the output process.
A few standard ICC profiles were already installed with the Prinect software; these can be selected from the respective list boxes. If you have generated your own ICC profiles, e.g. with "Prinect Color Toolbox", you can transfer them to the Prinect server. The ICC profiles are saved in their subfolders in a folder below the path "PTConfig\SysConfig\Resources\ICC Profiles\Printer" (PTConfig is the shared configuration folder of the Prinect server).
This is where you can add custom ICC profiles and create appropriate folders if required. DeviceLink profiles describe color transformation bypassing the L*a*b* color space and overwrite the set output profile. Doing without the L*a*b* interim color space gives you controlled transformation especially of the K separation.
"RGB images" / "RGB graphics" option
If this option is checked, RGB images or RGB graphics are clearly identified as "DeviceRGB" when an ICC profile is specified. The RGB images/graphics in the documents are transformed to the L*a*b* profile connection space with the help of the set ICC profile.
There is no transformation to the profile connection space and the images/graphics remain in the DeviceRGB color space if this option is not enabled. There is a standard RGB-CMYK conversion to the CMYK target color space during output. It is very likely that this output does not produce a satisfactory quality!
The ECI-RGB profile of the default becomes active when this option is enabled. However, you can also select a different profile.
Click "Browse..." to open a dialog where you can select a suitable ICC profile.
"CMYK images" / "CMYK graphics" option
If this option is checked, CMYK images or CMYK graphics are clearly identified as "DeviceCMYK" when an ICC profile is specified. Checking this option produces a CMYK > CMYK conversion. A CMYK image or a CMYK graphic is converted to the L*a*b* profile connection space with the profile specified here and then to the CMYK target color space. You should leave this option unchecked if you don't want any CMYK -> CMYK conversion.
On the other hand, a document must be matched to the target color space if the document was generated with a different process standard than the output process, for example, if the document was set up for uncoated paper but is to be printed on coated paper. A profile for coated paper is already set by default. In this case, a CMYK -> CMYK conversion must be made and this option must be checked.
After you enable this option, you must select an ICC profile from the pool of DeviceCMYK ICC profiles available in the Prinect system. However, you can also select a suitable output profile to confine the maximum print density.
Click "Browse..." to open a dialog where you can select a suitable ICC profile.
"Multicolor images" / "Multicolor graphics" option
To convert the multicolor images or multicolor graphics in the PDF document, select an ICC profile that is defined for a certain DeviceN color space, e.g. Hexachrome. In rare cases, a document can have several different multicolor color spaces. In such cases, you can only convert the images/graphics of one of these color spaces. The profile you select determines which type of multicolor images or graphics will be converted.
Click "Browse..." to open a dialog where you can select a suitable ICC profile.
Note: Inverse gamut mapping was not optimized for multicolor profiles ("perceptual" rendering intent for Multicolor -> CIEL*a*b*) because the ICC profile files would become very big due to the large number of color channels in multicolor color spaces. For that reason, we do not recommend setting a Multicolor -> CMYK conversion with "perceptual" rendering intent. This doesn't affect proofs because "absolute colorimetric" or "relative colorimetric" rendering intents are used for them. Multicolor profiles are optimized especially for proofing.
"Grayscale images" option
Normally, Color Management should not be applied to grayscale images and grayscale graphics when they are output (option is deselected). In certain cases, it may make sense to use ICC profiles for the output of grayscale images, for example, if you are going to output grayscale images with CMYK offset that are otherwise prepared for a newspaper process. Generally, such grayscale images have very little contrast when output without any matching. In this case, you can enable the "Grayscale Images" option and select a CMYK output profile matching the offset process as the profile (e.g. Offset Euro or Offset SWOP). As a result, a chromatic gray showing slight color is produced.
The use of special grayscale profiles ("Gray") instead of the CMYK profiles is a better alternative in this case. In this case, contrast is also improved without any color shifts. Some grayscale profiles are included in the Prinect software shipment.
Click "Browse..." to open a dialog where you can select a suitable ICC profile.
"Grayscale graphics" option
What was described for "Grayscale images" applies basically to grayscale graphics as well.
Note: The "Rendering Intent" and "BPC" parameters are dimmed if you select a "DeviceLink" profile in the "ICC/DeviceLink Profile" box (see "ICC/DeviceLink Profile" boxes) because these parameters are already contained in the DeviceLink profile.
The information about rendering intent and black point compensation as described in the "Color Management" tab (see Rendering Intent and "BPC" option) is applicable for other profiles.
"Grayscale images: Apply CMYK Profile" option
You can enable this option only if "CMYK images" is enabled and if "Grayscale images" is not enabled.
If this option is enabled, images in the device-dependent "DeviceGray" color space are transformed to the target color space with the ICC profile that is set for "CMYK images".
Checking this option produces a chromatic gray if the "Preserve in CMYK Images: K" option is not checked at the same time.
The original gray values are used without any conversion if this option is not checked.
"Grayscale graphics: Apply CMYK Profile" option
What was described for "Grayscale images: Apply CMYK Profile" applies to grayscale graphics as well.
"Preserve in CMYK Images/Graphics:" parameter
This parameter lets you keep black and, if necessary, also the chromatic colors in CMYK images or CMYK graphics:
•You keep black by checking the box next to "K" (separately for images and graphics).
•The chromatic colors are kept if you also check the box next to "CMY".
Preserve Black (K) in CMYK Images/Graphics
Jobs are often created deliberately with a "long" or "short" black, for example, with a short black to improve the impression of smooth screening in skin tones or with a long black to stabilize gray balance when reproducing black or metallic-colored technical equipment. Generally, you talk about a "short black" if only a little black ink (K) is used to improve the contrast and definition in dark areas. If black is used to replace more or less large but equal parts of the three chromatic inks C, M, Y in the color blending (under color reduction) and, by doing so, to reduce the volume of ink in the print, then we talk about a "long black".
If a job involves a process conversion (Color Management from CMYK to the CMYK of the planned output device), the length of the black channel in the output normally depends only on the makeup of the press profile. However, Heidelberg Color Management is able to modify black in the press profile during process conversion in such a way that it is similar to black in the input profile. This only works if the original black in the press profile is longer than black in the input profile.
This option affects the black portions in CMYK graphics and images. If the option is activated, black generation is retained as far as possible so that it matches that in the job. Color Management makes adaptations only when they are required to retain the visual impression of the black tone.
Note: We recommend that the "Preserve Black in CMYK Images/Graphics" option is always enabled, even if the jobs take slightly longer to calculate.
"Special", "Basic" and "K=K" options:
•Special (default)
This is a special setting that works as follows:
·C, M, Y are converted to the target CMY color space for mid-range and light hues. K is converted by means of a gradation curve.
·A special four-dimensional model keeping K is used for dark hues.
Extensive test series have shown this process to be the best. The "Special" parameter eliminates most of the problems in complex documents. This parameter is available only in Heidelberg's color management. This setting is suitable for documents with text, color and gray images.
•Basic
C, M and Y are converted to the target CMY color space, K is converted to the target density with the help of a gradation curve. The gradation curve solves any problems you may have with differing black ink densities. This setting is suitable for documents with grayscale images.
•K=K
Only C, M and Y are converted to the target CMY color space, K is not converted. Black remains identical. This setting is ideal for documents with a large amount of text and line art.
Note: The "K=K" setting can cause problems during an output if the black inks have different densities in the original and target color spaces.
Preservation of primary and secondary colors (Preserve CMY in CMYK Images/Graphics enabled)
This option keeps solid tint single-color or two-color image parts. You enable this option by checking the box next to "CMY" (separately for images and graphics).
Note: You can enable the preservation of primary and secondary colors regardless of the preservation of black.
Primary colors and secondary colors are preserved for CMYK images and graphics when you enable this option.
Normally, if color management is used, C=100, M=0, Y=0, K=0 becomes, for example, C=96, M=12, Y=8, K=2. In other words, "dirtying elements" creep in. These elements are fully correct if you have a true-color display. However, this behavior may not be wanted in technical diagrams because color margins occur at the mainly clearly defined edges, for example, due to register errors or if the maximum color of the original printing process is to be retained for this color area.
Secondary colors are colors that result from mixing two primary colors (100% in each case). C, M, Y and K are the primary colors in the CMYK color model. Secondary colors are "red" (C=0, M=100, Y=100), "green" (C=100, M=0, Y=100) and "blue" (C=100, M=100, Y=0). These colors are not "real" RGB colors but result from superposing the respective pairs of CMY colors.
When secondary colors are preserved, blue (C=100, M=100, Y=0, K=0), for example, doesn't change. The influence of color management causes C=100, M=100, Y=0, K=0 to become C=97, M=94, Y=3, for example. The selection of "+secondaries" makes sure that this blue stays C=100, M=100, Y=0, K=0. The preservation of secondary colors is always in addition to the preservation of primary colors. This is highlighted by the plus sign.
There are the following variants for the preservation of primary and secondary colors:
•Primaries (solid)
Only solid tint primary colors with a value of 100% are kept, e.g. 100% magenta.
•Primaries (all)
All primary colors (including those less than 100%) are kept, e.g. 78% magenta.
•+ Secondaries (solid)
In addition to the primary colors, solid tint secondary colors with a value of 100% are kept, e.g. green made up of 100% yellow and 100% cyan.
•+ Secondaries (all)
In addition to the primary colors, all secondary colors (including those less than 100%) are kept, e.g. green made up of 80% yellow and 80% cyan.
Caution: You should enable the preservation of primary / secondary colors only if, for technical reasons, the colors really have to be kept and not be influenced by color management. You should never enable these options by default as otherwise you can have results that you may not want in your printing.
"Color Management for Overprinting Device CMYK Graphics" option
The overprint property of some CMYK channels can be lost as a result of enabling color management. When this option is checked, color management is enabled for overprinting device CMYK graphics. This option should be disabled if it is more important to keep the overprint property than use color management.
"Color Management for Subsets of Device CMYK" option
If this option is checked, a CMYK input profile is used also on subsets of device CMYK images or smooth shadings Example: Multi-channel color space (DeviceN) with cyan and magenta.
"Color Management for Device CMYK with Active Color Blending" option
In rare cases, visible color deviations result when Color Management is applied to objects in Device CMYK with active color blending.
You can disable this option to avoid color deviations in such cases. Color Management is then not applied to such objects.
"Color Management for CMYK Spot Colors Mapped to CMYK" option
This option lets you control whether and how Color Management will be applied to spot colors that are present in their CMYK equivalents. The following options are given:
•The option is disabled: Color Management is not applied to spot colors converted to CMYK.
•The option is enabled and "All Colors" is set in the list box: Color Management is applied to all spot colors converted to CMYK.
•The option is enabled and "Colors from PDF" is set in the list box: Color Management is applied only to spot colors converted to CYMK whose ink recipes for CMYK replacement are defined in the PDF and not in the job settings.