"Color Management" tab

In this tab, you set how device-independent colors will be handled and matched to the target color spaces.

"Device independent Colors" group

In the characterization of a digital camera, for example, the device-specific characteristics are captured as a set of characterization curves. At the same time, the RGB data of the device are transformed into the CIEL*a*b* color space and saved in an "input ICC profile". If this ICC profile is enabled when reading out the digital image data, image data with standardized colors are created in the CIEL*a*b* color space. These transformed image data are now "device-independent". The following types of device-independent colors exist:

•CMYK/grayscale images

•CMYK/grayscale graphics

•RGB/L*a*b* images

•RGB/L*a*b* graphics

•Spot Color Images

•Spot Color Graphics

The "L*a*b*", "CalibratedRGB" and "CalibratedGray" color spaces are regarded as device-independent as they are uniquely identified.

"Treat ICCBased CMYK as Device CMYK" option

All embedded CMYK ICC profiles are removed from the document files if this option is checked. This means: the documents in the device-independent CMYK color space are treated as device-dependent documents in the "DeviceCMYK" color space with the appropriate settings.

For that reason, the embedded ICC profiles are used for conversion to the target color space. In other words, there is a "CMYK -> CMYK conversion".

"Treat ICCBased RGB and Calibrated RGB as Device RGB" option

All embedded RGB ICC profiles are removed from the document files if this option is checked. This means: the documents in the device-independent RGB color space are treated as device-dependent documents in the "DeviceRGB" color space with the appropriate settings.

Colors from the "CalRGB" color space are converted to the "DeviceRGB" color space without color management. Afterwards, the colors are converted to the target color space using color management with the ICC profiles set in "RGB Image" or "RGB Graphic".

The embedded ICC profiles are used for conversion to the target color space or colors from "CalRGB" are treated as "sRGB" in compliance with the PDF specification and converted to the target color space if this option is not checked.

"Treat ICCBased Gray and Calibrated Gray as Device Gray option

All embedded Gray ICC profiles are removed from the document files if this option is checked. This means: the documents in the device-independent Gray color space are treated as device-dependent documents in the "DeviceGray" color space with the appropriate settings.

The color is used in the K separation. This setting prevents a "chromatic" gray.

The embedded ICC profiles are used for conversion to the target color space or colors from "CalGray" are converted to the target color space in compliance with the PDF specification if this option is not checked. Remember that the color then contains CMY.

Rendering Intent

In addition to selecting ICC profiles, you can set the rendering intent for the individual graphics/image types. Rendering intent determines how the color space adaptation should be executed: Since losses always occur during a color space transformation, it can be helpful to, for example, retain the photographic perception of an original and to accept a limit on the number of color values.

For images and graphics in spot colors, you can also select a rendering intent if the spot colors are defined in an alternate color space like ICCBased-RGB, Calibrated RGB or CIEL*a*b*. This means that you can set a rendering intent also for output in multicolor color spaces, e.g. in the Hexachrome color space.

The following parameters are available for rendering intent: "From Document", "Absolute Colorimetric", "Relative Colorimetric", "Saturation" and "Perceptual".

•From Document

The Color Rendering Intents that were defined for images and graphics in the PDF documents are used.

Note: You should select "From Document" only if you are absolutely sure that the edited documents have a rendering intent setting that can correctly control the color space conversion desired. However, you should not use this setting if at all possible because this is very seldom the case.

•Saturation:

In the output, the colors are rendered in such a manner that the color saturation is retained or even emphasized. The type of color matching is manufacturer-specific, with the user being able to define some settings during profile generation. This option is suitable for business graphics where the color saturation is the most important attribute in color rendering.

•Perceptual:

When you use the "Perceptual" parameter, you obtain an output, that essentially contains the perceptible impression of the original. This means that the precise, colorimetric rendering of the colors is modified in favor of the retention of the relative color relationships. In a smaller target color space, the color gamut is compressed accordingly. Vice versa, in a larger target color space and with suitable profiles, the color space may be expanded. With this color matching option, the hue in all the natural colors of the original is reproduced for the most part correctly but with restrictions in the contrast. The type of color matching is manufacturer-specific, with the user being able to set some of the aspects such as contrast and chroma change during profile generation. This option is especially suitable for photographs.

•Relative colorimetric:

Colors are rendered taking solely the light source into account. The rendering intent of the print medium (e.g. the color of the unprinted paper) is not taken into account. For example, the illuminant of a monitor would be correctly rendered on the print medium. That is why the term "relative" is used. All colors that lie within the target color space are rendered identically. All colors that lie outside of the target color space are displayed on the margin of the target color space. That is why the term "colorimetric" is used.

The advantage of this rendering intent is that different illuminants of different output media are taken into account. The disadvantage is that the color adaptations are not exactly retained when switching from one output medium to another. As a result, very dark or very colorful details in the originals can be lost when they are reproduced. The printing material is not simulated during an output process simulation. If production run paper is used during the simulation, the result is the same as if you used the "absolute colorimetric" rendering intent. This rendering intent is suitable mainly for vector graphics.

•Absolute colorimetric:

Colors are rendered taking the light source and the medium illuminant (e.g. the color of the unprinted paper). For example, the illuminant of a newsprint paper which is shifted from illustration printing paper towards yellow compared to the illuminant of paper is rendered with a yellowish cast. That is why the term "absolute" is used. That is why "Absolute colorimetric" is the default setting for a proof output. All colors that lie outside of the output color space are displayed on the margin of the output color space.

The advantage of this rendering intent is that the exact color values are retained when switching from one output medium to another. The disadvantage is that any colors that lie outside of the output color space cannot be distinguished. This rendering intent is especially suitable for logos or monochrome objects which must be reproduced exactly the same way on different output media. You can set a separate rendering intent for spot colors that is independent of the color space of the alternative display color. "Absolute colorimetric" is recommended. This makes sure that the spot colors are simulated as best as possible.

Note: You should define the following settings for rendering intent if you want true-color proofing:

·You should use "Relative Colorimetric" rendering intent if you do not need paper white simulation.

·You should use "Absolute Colorimetric" rendering intent if you need paper white simulation. Consequently, all colors in common of the source and target color space are rendered identically. It makes sense to use this rendering intent since a proofer normally has a wider gamut than the print process it simulates. In case colors in the color file you want to proof extend beyond the proofer's gamut, these colors will be mapped to the "edge" of the proofer color space. This means, all colors not covered by the proofer's color space are rendered with those colors the proofer can just about support. As a result, shadow areas may lose detail.

The "Perceptual" and "Saturation" rendering intents are not suited for proofing.

"BPC" option

Black point compensation (BPC) becomes active if you enable the "BPC" option. You can enable black point compensation (BPC) for "Relative Colorimetric" "Perceptual" and "Saturation" rendering intents. However, the effect of this option can only be seen for the rendering intent "Relative Colorimetric".

In gamut mapping, all L shadows (in the L*a*b* color space) that are darker than black toner/ink are matched to black toner/ink and, as a result, shadow definition is lost.

Black point compensation is similar to Photoshop's "Use Black Point Compensation" option.

Black point compensation enhances the reproduction area when the "Relative colorimetric" rendering intent is used for color space conversion to the L*a*b* color space or from the L*a*b* color space to the device color space. The L*a*b* color space has more lightness levels for dark image parts than the CMYK color space because the L*a*b* color space is larger than the CMYK device color space. In a color space conversion from the L*a*b* to the CMYK color space with "Relative Colorimetric" rendering intent, the color space is cut off or reproduced without definition in the shadows because they are located outside the displayable range. As a result, details in dark parts of the image are often lost, especially if ICC profiles for uncoated papers are used for color space conversion.

Black point compensation matches the black point during color space conversion, causing the definition in such dark image parts to be kept. This "elongates" the shadows causing color shifts to occur also in the lighter color values. For that reason, this method is not always suited to true-color proofing.

We recommend that you use "Perceptual" rendering intent with black point compensation and not "Relative Colorimetric" rendering intent. This rendering intent makes it possible for the various details in dark image parts to be reproduced, while keeping color shifts to a minimum. In principle, differences cannot be fully avoided because of the different sizes of the color spaces.

"Output" Group

In this group you define an ICC profile for transformation of the color space to the target color space of the printing process and set the related options.

"Press Profile" box

This is where you set a color profile for the output process or the printing press used. You can customize your printing process, e.g. to regionally specific printing processes (SWOP, EURO, etc.), by selecting a suitable profile.

You can assign the press profiles to different target color spaces depending on your output:

•Normally you use a "DeviceCMYK" profile for presses.

•You can use a "DeviceGray" profile for a black-and-white output.

•You can use a "DeviceRGB" profile for a monitor output (e.g. a page in the web).

Click "Browse..." to open a dialog where you can select a suitable press profile.

Note: You will find an overview of all the ICC profiles available in the Prinect system in "Administration" > "Resources" tab > "ICC Profiles". You can also import new profiles, create new profile folders, delete profiles, etc. there. The ICC profiles are filed in "SysConfig\Resources\ICC Profiles". "SysConfig" is the shared configuration folder on the Prinect server.

"Use Press Profile from Job Settings, if Available" option

An output press profile that was assigned to the job in the job settings in the "Colors" or "Printing Process" tab is used if this option is enabled.

In the job settings you can check in "Consistency Check" in the "Printing Process" tab whether a press profile that you will assign to the job is suitable for this purpose.

•If there is a green dot in front of the selected press profile, you can process the job with the selected press profile.

•There is a conflict if there is a yellow triangle before the selected press profile. If this is the case, you should use a different press profile.

"Use PDF/X Output Intent, if available, as Press Profile" option

•The Prinect Manager behaves as follows if this option is enabled:

When a PDF/X file with an embedded ICC profile as its Output Intent is processed, the embedded press profile is used for color space conversion. The press profile set in "Press Profile" is ignored.

If there is no Output Intent, the ICC profile set in "Press Profile" will be used.

•The press profile set in "Press Profile" is used for color space conversion if this option is not checked.

Any embedded PDF/X Output Intent will not be used for color space conversion during output.

If you wish to process jobs in the Prinect workflow using the PDF/X policies, you must always enable this option.

"Embed Applied Press Profile as PDF/X Output Intent" option

The used press profile is embedded in the PDF file as the PDF/X Output Intent if this option is checked. The embedded ICC profile specified as the Output Intent replaces the profile set in "Press Profile" and is used for output if the "Use Embedded PDF/X Output Intent, if Available, as Press Profile" option is also checked and there is a PDF/X Output Intent in the processed PDF/X file. In addition, this embedded profile will be embedded as the new Output Intent during export. This option can be good policy for data interchange.

In all other cases, except in multicolor profiles, the profile set in "Press Profile" is embedded in the PDF file as the PDF/X Output Intent. This embedding is not possible in multicolor profiles.

The set press profile is not embedded in the PDF file as the PDF/X Output Intent if this option is not checked.

"Use PDF/X Output Intent, if available, as CMYK input profile" option

If you enabled this option, a PDF/X file with a defined Output Intent and embedded ICC profile is always used as the input profile for CMYK images and CMYK graphics if you are going to process such a file. The ICC profiles set for this purpose in the "Device Colors/Device Link" tab will be ignored.

"Device Colors/Device Link" 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 is transformed to the device-independent L*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 profile, for e.g. color printers, imagesetters

•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 Profile 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

RGB images or graphics are clearly identified as "DeviceRGB" when an ICC profile is specified if this option is checked. 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 RGB 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

CMYK images or graphics are clearly identified as "DeviceCMYK" when an ICC profile is specified if this option is checked. 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 to the output process, for example, if the document was separated 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 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.

Rendering Intent

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.

"BPC" option

In gamut mapping, all L shadows (in the L*a*b* color space) that are darker than black toner/ink are matched to black toner/ink and, as a result, shadow definition is lost.

Black point compensation is similar to Photoshop's "Use Black Point Compensation" option.

"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" applies accordingly 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

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.

"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.

Note: We recommend that the "Preserve Black in CMYK Images/Graphics" option is always enabled, even if the jobs take slightly longer to calculate.

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 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 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 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.