"Color settings" tab for Jetfire 50 digital presses

Switching between Prinect color management and Jetfire Frontend color management

"Enable Color Management" option

This option allows you to switch between two color management processes:

​•​If the "Enable Color Management" option is selected, HEIDELBERG Prinect color management is used for print output. HEIDELBERG Prinect color management transforms all colors in the job into an intermediate color space (L*a*b*) and then into the output color space of the Jetfire 50 press. This setting disables the color management of the Jetfire frontend.

​•​If the "Enable Color Management" option is disabled, the color management of the Jetfire frontend is used for printing. In other words, the Jetfire Frontend color management uses the press and paper profiles to convert the colors directly into the output color space. The Prinect color management is completely bypassed, i.e., none of the corresponding settings have any effect on the print output. In this operating mode, there may be latency times during print output, especially when outputting PDF/VT jobs, as the conversion of the job colors to the intermediate color space must first be completed by Prinect color management before the job is submitted to the Jetfire front end. After submission to Jetfire Frontend, Prinect can render the other job data somewhat faster than if the "Enable Color Management" option is activated, as the conversion to the output color space does not take place within the Prinect workflow.

Note: If you use the Jetfire 50 digital press in a "hybrid" workflow, i.e. in a Prinect system environment with additional other presses, e.g. HEIDELBERG offset presses or Versafire digital presses and an additional color proofer, the use of Prinect Color Management ensures that the same color management parameters (profiles and algorithms) are applied to all presses connected to the Prinect workflow for print output. This ensures uniform color processing of all print jobs, even if different presses are used. We recommend enabling HEIDELBERG color management, especially if a color proofer is also to be used in order to obtain a true to color preview of the print results.

Prinect Prinect Color Management Settings

Prerequisite: The Prinect color management settings only have the effect described below if the "Enable Color Management" option" is enabled. If the option is disabled, only Jetfire Frontend color management affects the print output.

 "Source Profiles" group

This is where you set up your input profiles for color management.

 CMY colors

This is where you define the source profiles solely for documents that contain CMYK colors.

"Enable CMYK Color Management" option

Use this option to specify that a CMYK input profile will be used for color conversion.

Note: Except for the selection of the input profile, the parameters for CMYK color management are also applicable for grayscales.

If this option is disabled, the documents are not processed with the Prinect Color Management. This option is necessary, for example, if the digital print outputs are to be used for color calibration (e.g. with Prinect Color Toolbox). In this case, the output documents may not be processed with color management. Neither a CMYK input profile nor an output profile will be used.

Note: Color management for documents with solely RGB and/or grayscale colors remains enabled even if "Enable CMYK Color Management" is disabled.

Note: If Prinect Color Management is disabled, i.e., if the "Enable Color Management" option is not selected, Jetfire Frontend color management affects the print output. In this case, to ensure true.to.color output for color calibration, you must make sure that no color management functions in the Jetfire Frontend settings affect the uncalibrated print output. As an alternative, we recommend enabling Prinect Color Management for such output and disabling the "Enable CMYK Color Management" option.

"Use Embedded Profiles" option

If documents containing colored objects or images are to be output, these objects are automatically converted so that they can be output in the CMYK or grayscale color space. The input profiles required for the input color space -> profile connection space transformation are usually included in the PDF documents and are used by color management. If the PDF documents do not have an input profile, you can use the standard input profile set by default or select a different one using the Browse button.

With the option "Use Embedded Profiles", you generally enable the use of profiles embedded in the PDF documents. If no embedded profile is known, you can select which CMYK input profile should be used by clicking the folder icon. You can also set the following parameters here:

​•​In the "RI" listbox, you can select a rendering intent for the CMYK colors.

​•​The "TK" option can be enabled or disabled.

Note: The profiles that are selected are checked for suitability for the current context. A warning is issued if an unsuitable profile is selected.

You can create input ICC profiles – unless appropriate device profiles are already available – for example with "Prinect Color Toolbox" and file them on the Prinect Server. The ICC profiles are saved in subfolders of "PTConfig\SysConfig\Resources\ICC Profiles" (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.

Note: In "Administration" > "Resources" > "ICC Profiles" you can see an overview of all the ICC profiles available in the Prinect workflow. See ICC profiles. You can also import new profiles, create new profile folders, delete profiles, etc.

Separate input profile settings for image and text elements or graphic elements

By default, the "Input Profiles", "Rendering Intent" and "BPC" (black point compensation) parameters are available for CMYK and RGB colors for image, text and graphic objects. This means that the set parameters (input profile, rendering intent, black point compensation) are valid for image, text and graphic objects.

Click the plus sign beside the "Images" icon to display the same parameters for image elements and for text/graphic objects separately. In this way, you can set up the input performance of color management separately for image/text objects and for graphic objects.

The settings that currently can be seen always affect color management.

​•​Collapsed (plus sign displays): joint settings for image, text and graphic objects.

​•​Expanded (minus sign displays): separate settings for image objects and text/graphic objects.

Rendering Intent (RI)

In addition to selecting ICC profiles, you can set the rendering intent for the colored objects. Rendering intent determines how color matching is done. Since losses always occur during a color space transformation, it can be helpful, for example, to retain the photographic perception of an original and to accept a limit on the number of color values. The following parameters are available for rendering intent: "Perceptual", "Saturation", "Relative Colorimetric" and "Absolute Colorimetric":

​•​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 space 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.

​•​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.

​•​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 output color space are rendered identically. All colors that lie outside of the output color space are displayed on the margin of the output 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 substrate 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) into consideration. 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.

Note: "Absolute colorimetric" is always set as the rendering intent for spot colors. This makes sure that the spot colors are simulated as best as possible.

​•​From Document

The Color Rendering Intents that were defined for images and graphics in the PDF documents are used. Normally, "relative" is set as the rendering intent in the PDF documents. However, different rendering intents may have been assigned to single objects. In such cases, the object-related rendering intent is used if this option is set. If necessary, you can check such PDF documents in advance, for example, with Prinect PDF Toolbox.

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

"BPC" (black point compensation) 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 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.

"Keep CMYK Colors" parameter

When this option is enabled (any other item than "OFFF" is selected), CMY in solid tint single-color or two-color image parts is kept.

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.

"Primaries (solid)" selected

Cyan, magenta, yellow and black (K) are the primary colors in the CMYK color model. When this is selected, only the solid tint primaries with a value of 100% are kept in their original color percentages, meaning that they are not changed by color management. Example: 100% Magenta.

"Primaries (all)" selected

When this is selected, all the primaries (including those less than 100%) are kept in their original color percentages, meaning that they are not changed by color management. Example: 70% Magenta.

"+ Secondaries (solid)" selected

Secondary colors are colors that result from mixing two primary colors (C, M,Y). 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) in the CMYK color model.

The preservation of secondary colors is always in addition to the preservation of primary colors. This is highlighted by the prefixed plus sign.

When secondary colors (solid tint) are preserved, solid tint secondaries each with 100% are kept in addition to the primaries, e.g. blue (C=100, M=100, Y=0).

By clicking the plus sign in front of the list box, you can set up that CMYK colors will be kept separately for images and graphics.

"+ Secondaries (all)" selected

When secondary colors (all) are preserved, all the secondaries are kept in addition to the primaries, even if originally they are not made up of 100% primaries. For example, red (C=0, M=80, Y=80, K=0) doesn't change.

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.

Note: Objects or documents in the "Gray" color space are not handled by color management if "Preserve colors" is enabled.

 RGB colors

"Use Embedded Profiles" option

This option lets you define which RGB input profile will be used:

​•​If this option is enabled and a device-dependent input profile is embedded in the PDF documents, then this profile will be used as the input profile.

​•​If this option is enabled and no input profile is embedded in the PDF files, the RGB ICC profile selected will be used for color management.

​•​If this option is not enabled, the RGB ICC profile selected will always be used for color management.

Note: The profiles that are selected are checked for suitability for the current context. A warning is issued if an unsuitable profile is selected.

Apart from this, the annotations made for CMYK colors are applicable for profile selection, rendering intent and black point compensation. See "Use Embedded Profiles" option.

 Keep Black

Prerequisite: This option is available only if the "Enable Color Management" option is enabled (Prinect Color Management enabled).

Note: If PDF documents with grayscale content are output, normally black in the CMYK input profile is used for grayscale color management. Exception: If you enable "Always Keep Black on B/W Pages" and/or "Keep Black in Images" or "Keep Black for Text / Graphics", the settings of the input profile are not used for color management.

"Keep Black in Images" option

If this option is enabled, only C, M and Y are converted to the target CMY color space in images, K is not converted. Black remains identical.

Note: This setting can cause issues during an output if the black inks have different densities in the original and target color spaces.

"Match Lightness" option

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. This setting eliminates most of the problems in complex documents. This function is available only in HEIDELBERG's color management. This setting is suitable for documents with text, color and gray images.

"Keep Black for Text / Graphics" option

If this option is enabled, color management does not affect black in the text or graphic objects. The following options are available for this:

​•​All

Black defined for output remains unchanged for all text and/or graphic objects that only contain black. In other words, color management does not affect black definition.

Note: If "Keep Black for Text / Graphics > All" is enabled and a page has no other separations except for black, this is highlighted in the preview by a black separation icon.

This lets you see right away whether a sheet with apparently black content really only contains the black separation. Otherwise it might be printed unintentionally in several colors.

​•​Keep 100% Black

When enabled, this option has the following impact: If black is defined as C=M=Y=0 and K=100% or as R=G=B=0 and/or gray=0 in text or graphic objects, black is kept as 100% black or the colors are set to C=M=Y=0 and K=100%.

"Black Overprint" option for text / graphics

The "Overprint" function is mostly used to avoid register problems and flashes in black fonts and other black graphic objects that lie on top of a colored background. For design purposes, overprint is also used with hard shadows or colored CMYK objects. You can control overprint best if it is set directly in the application that creates the job.

The overprint settings of Prinect Color Management on the one hand serve to compensate for application shortcomings and on the other hand to process faulty documents so that you get the overprint effect you want. It's not possible to detect on a page which object is to overprint and which not. For that reason, these settings are not sufficient in some individual cases.

All black elements defined as knockout are set to "overprint" if this option is enabled.

This option affects the following color spaces: "DeviceCMYK" with C=M=Y=0%, "DeviceGray" or "/Separation/Black". You can use this option specifically on text and/or graphic objects.

 Spot colors

Prerequisite: This option is available only if the "Enable Color Management" option is enabled (Prinect Color Management enabled).

The setting options display when you click the triangle.

In this group you specify whether varnish, white and/or spot colors defined as "DieLines" will be printed.

The settings for varnish or for white display depending on the features of your press.

"Remove Transparent Spot Colors" option

Spot colors can be defined as "transparent". This is set in "Colors" in the job settings. See Type. Generally, transparent spot colors are used as varnishes.

When this option is enabled, all spot colors defined as "transparent" are removed from the printing data. You should enable this option if the press has no coating unit.

You must disable this option if a coating unit is available and if it is to be used to output transparent spot colors.

"Remove 'DieLine'" option

"DieLine" spot colors will not be printed if this option is enabled. The "DieLine" spot color is usually used as a proof color in PDF documents, for example, to display proof marks. If a proof is to be made of the current print job, you can disable this option for proofing. You should enable this option for the production run.

"Map Spot Colors to Process Colors" option

Caution: If the print job contains overprinting spot colors, it is strongly recommended to disable the option "Convert spot colors to process colors" in the "Spot colors" settings area or leave the option disabled. The overprint emulation of the Jetfire Frontend frontend is used if this option is disabled.

When this option is enabled, spot colors are not output as separate color separations but are converted to CMYK colors.

The impact of this option is visualized in the sheet preview.

Note: The spot colors that are set in "Colors" in the print job are always used in the "Digital Printing" step. See "Colors" Group.

​•​PDF documents generally have "recipes" for replacing the spot colors in the document by process colors (CMYK replacement). In other words, each spot color in the document has set CMYK values that replace this spot color. In "Colors" you can set which replacement policies will be used, those in the job settings or those in the PDF documents.

​•​The "Administration" section of the Prinect Cockpit also has recipes for spot color replacement in "Color Tables". In "Colors" you can set which replacement policies will be used, those in the job settings or those in "Administration > Color Tables".

"Spot Color Matching" function

Prerequisite: The "Spot Color Matching" option is operable only if the job contains spot colors.

You can use "Spot Color Matching" if you need special settings for spot color replacement. This function lets you customize the settings for replacing spot colors in your current print job.

Note: If a color profile is set in the job and it deviates from the output profile defined in the digital print settings of Prinect Production, then a warning is issued whenever you try to open the "Spot Color Matching" dialog. This warning draws your attention to the fact that spot color matching is not possible because of the different color profiles. You can choose to apply the output profile of Prinect Production for spot color matching or to cancel spot color matching.

We recommend that you have a probe of the correct spot color in the original on hand before you start color matching to be able to compare the printouts of the test charts with this probe.

Note: The settings always relate to a specific paper grade on a specific press.

​1.​Click "Spot Color Matching".

The "Spot Color Matching" dialog opens.

​2.​In the "Color Name" list box, first select the spot color for which you want to define a substitute color. All the spot colors that are in the current print job are listed.

The original color displays in "C4", the middle color patch. Modified colors display around the original color. Colors that cannot be output correctly to the paper set in the print job are marked by an "x".

The ΔE 2000 value of the currently selected color patch displays below the color patches. When you move the mouse pointer over a different color patch, the current ΔE 2000 value of this patch displays. This is a fast way to view the differences to the original color and find an optimal substitute color.

The aim of these settings is to determine a color that optimally replaces the original spot color, allowing it to be output correctly (in other words, a color that is not marked by an "x").

​3.​Click "Print Test Page".

Note: Each color patch in the test charts is labeled with the CMYK and L*a*b* values of the color. This makes it easy to apply the color values to the print job.

​•​A test chart is printed immediately if the job does not have any spot colors.

​•​The "Print Test Page" dialog displays if the job has one or more spot colors:

This is where you can set that test charts will be printed for all spot colors at the same time or for one or more spot colors.

"Add White Background" option

The test page can be given a white background to enhance the color impression when assessing a spot color, for example, when printing to foil.

Prerequisite: The "Add White Background" option is available only for presses that have an inking unit for "White" (e.g. Versafire CV/EV, Labelfire 340).

Enable "Add White Background" to use this function.

"TrimBox" option

The trim box is also output with cut marks when you enable this option. This makes it easier to cut the test prints, if required.

Note: Each test chart printout creates a new separate print job in Prinect Production. These test chart print jobs are set up with the color settings that are required for a true-color output. Test chart output only occurs on the Labelfire press if an additional proofer is defined in the output sequence.

​4.​Now compare the printout of the test chart with the original copy and determine the color patch that best matches the original spot color.

​5.​If the deviation is still too big, enable either "Lightness/Chroma" or "Color Cast" in "Correction" to set the type of color change. Now move the "Step width" slider until suitable patches display in the preview window. The bigger the step width, the greater the differences between each of the color patches.

​6.​Repeat steps 3 and 4 until you are satisfied that the target color is determined accurately enough. On the test chart, the patch with the correct color has an "address" e.g. "D 6".

​7.​Click the "D6" patch in the "Spot Color Matching" dialog.

The CMYK values or the L*a*b* values (whichever one is defined) of the original color display in "Original Color". The values of the selected color display accordingly in "Selected Color" (in our example, those of "D6").

Note: The values of the target color are always specified as CMYK values even if the original color is set in the L*a*b* color space (exception: inkjet presses, see below).

​8.​Enable "Edit alternate color in job colors" if you wish to set the alternate color only for the current print job.

If the alternate color is always to be set for the paper grade used, enable "Use alternate color always for paper grade "..." on (...)" and select the paper grade that will be used for printing the test page in the "Customize for" list box. Then these settings affect all print jobs that are printed with this paper grade on this press. This setup is applicable until you edit it again.

​9.​If you are satisfied with the colors selected, confirm the dialog with "Save".

​10.​Use the "Delete" button to reset all the settings so that special spot color settings are no longer defined for the particular paper grade/press combination.

The "Paper Grade" and "Output Device" boxes are for your information only.

Note: When you close the "Spot Color Matching" dialog, the settings made last are retained and will be used again the next time the dialog opens again.

 Target profile

Prerequisite: This option is available only if the "Enable Color Management" option is enabled (Prinect Color Management enabled).

This is where you can define the "target profile" of the Prinect Color Management, in other words the target color space of print output. This target profile affects all outputs on the paper grade selected. The target profile defined here is embedded as OutputIntent in the PDF document generated for output via Jetfire Frontend.

 Machine color settings

Option "Color presets"

Here you can choose the following color presets for the Jetfire 50:

​•​None

No specific color presets are used.

​•​Office documents

Color presets for Office documents are used.

​•​Photographic content

Color presets for photographic content are used.

Color settings "For Body", "For Cover", "For Selection"

For Jetfire 50 presses and in Jetfire Frontend, the substrates used are organized into so-called "media families". Several "material print modes" can be defined for a "media family" in which different print parameters are grouped together, e.g.,

​•​Output ICC profiles

​•​Drier temperature

​•​Procedure for the quality elements on the individual pages

​•​Strategy for keeping individual nozzles open (as a bar or distributed across the page)

​•​optional: Using the Jetfire Frontend color functions

​•​Ink limits

​•​etc.

"Media print mode" listbox

The Media print mode is the most important parameter for output quality control in Jetfire Frontend. Therefore, the appropriate media print mode must be selected for each selected paper (the effect on print quality is comparable to selecting the output profile on a Versafire machine).

In this list box, you can select the media print mode to be applied.

"Convert to Gray" option

When you enable this option, the part in question (body, cover, selection) is output as a grayscale even if it contains color pages. This setting displays in the preview.