Step by step - Learn how to use callas productsNew in pdfToolbox 11 Convert colorsConvert colors: Advanced settings (previously "Policies")

Convert colors: Advanced settings (previously "Policies")

The regular ICC based color conversion is extended by some useful options. This includes obtainment of pure black, recognition of RGB black or adaption of tone value increase. Additional parameters for controlling these properties can be defined in the "Advanced settings" tab, that can be selected in the "Convert colors" Fixup.

You will find details on parameters and example configurations on the following pages. 

Old, deprecated configuration using Policy files

Before pdfToolbox 11, these options were defined by config files, which were completely text based and could be modified with a simple text editor. Exported color conversion profiles were containing these additional files.
You'll find the documentation of this deprecated implementation here: Policies

Overview

All parameters defined in the "Advanced settings"-tab take precedence over all settings defined in the user interface. Please note that nonetheless only objects triggered due to the "Conversion settings" in the user interface will be changed.

The following parameters are available (please consult section Parameter for a detailed explanation):

Parameters

RenderingIntent

Keys

  • CMYKGraph-RenderingIntent
  • CMYKImage-RenderingIntent
  • RGBGraph-RenderingIntent
  • RGBImage-RenderingIntent
  • GrayGraph-RenderingIntent
  • GrayImage-RenderingIntent
  • LabGraph-RenderingIntent
  • LabImage-RenderingIntent

Values

Use Rendering Intent of document

Rendering Intent specified in the PDF is used (default)

RelativeColorimetic

Relative colorimetric

AbsoluteColorimetric

Absolute colorimetric

Perceptual

Perceptual

Saturation

Saturation

Description

This parameter defines which Rendering Intent is used for a color conver­sion. This parameter overrides the option Rendering Intent of the con­version settings.

  • Note: If there is no Rendering Intent explicitely defined in the PDF the default is "Relative Colorimetric".

C_eq_M_eq_Y_is_Black

Keys

  • CMYKGraph-C_eq_M_eq_Y_is_Black
  • CMYKImage-C_eq_M_eq_Y_is_Black

Values

Ignore parameter

Convert as defined for color space CMYK (default)

DeviceGray

Use DeviceGray

DeviceCMYK Black

Use DeviceCMYK Black

Separation "Black"

Use Separation Black

If only the black channel is used, the object will be converted according to the settings for color space Gray and stored in the defined color space afterwards. This parameter overrides the option Preserve black objects of the destination settings for CMYK.

C_eq_M_eq_Y_isBlack_ExcludeBlendModes

Keys

  • CMYKGraph-C_eq_M_eq_Y_is_Black_ExcludeBlendModes
  • CMYKImage-C_eq_M_eq_Y_is_Black_ExcludeBlendModes

Values

<List of all Blend modes> Name of Blend modes to exclude from color conversion
To exclude multiple Blend modes, one setting for each blend mode has to be configured

Description

Objects, which are using a Blend mode listed in this parameter, will be processed using the normal color conversion and no preservation of black objects will take place.
This might be appropriate for objects (with empty colorant channels), that are using certain blend mode, which are using these empty channels to achieve a special effect with underlying objects.
If these empty channels would be replaced by a single colorant color space, these effects would not work anymore, so they must be preserved in some certain cases.

Please see article "Processing black objects" for further details.

R_eq_G_eq_B_is_Black

Keys

  • RGBGraph-R_eq_G_eq_B_is_Black
  • RGBImage-R_eq_G_eq_B_is_Black

 

Values

Ignore parameter

Convert as defined for color space RGB (default)

DeviceGray

Use DeviceGray

DeviceCMYK Black

Use DeviceCMYK Black

Separation "Black"

Use Separation Black

Description

This parameter only applies to device dependent RGB color – either if the object uses DeviceRGB or if it uses ICC based RGB or CalRGB but the parameter StripSourceProfile is set to On. It only has effect if ConvertToDestination is set to On. If not set to NoChange, instead of carrying out an ICC based color conversion, RGB colors where each of the Red Green and Blue values are equal, will be converted directly to the corresponding black tint value. For images this will only have an effect if all pixels in the image have equal Red, Green and Blue values.
The color conversion engine uses an internal tolerance of 3%, this mean the differences between R and G, G and B as well as for R and B must be <=3%.

R_eq_G_eq_B_is_Black_ExcludeBlendModes

Keys

  • RGBImage-R_eq_G_eq_B_is_Black_ExcludeBlendModes
  • RGBGraph-R_eq_G_eq_B_is_Black_ExcludeBlendModes

Values

Blend mode Name of Blend modes to exclude from color conversion
To exclude multiple Blend modes, one setting for each blend mode has to be configured

Description

Objects, which are using a Blend mode listed in this parameter, will be processed using the normal color conversion and no preservation of black objects will take place.
This might be appropriate for objects (with empty colorant channels), that are using certain blend mode, which are using these empty channels to achieve a special effect with underlying objects.
If these empty channels would be replaced by a single colorant color space, these effects would not work anymore, so they must be preserved in some certain cases.

Please see article "Processing black objects" for further details.

SetGrayColorSpaceTo

Keys

  • GrayGraph-SetGrayColorSpaceTo
  • GrayImage-SetGrayColorSpaceTo

Values

Keep color space for Gray

Convert as defined for color space Gray (default)

DeviceGray

Use DeviceGray

DeviceCMYK Black

Use DeviceCMYK Black

Separation "Black"

Use Separation Black

Description

This parameter applies to gray vector and image objects. It indicates which color space to use for gray objects after the conversion. For example, it may be necessary to encode a DeviceGray object as Separation Black object, so that overprinting also works for subjacent CMYK objects.

  • Note: DeviceGray cannot overprint CMYK, even if overprint is set to true, whereas Separation Black does overprint Cyan, Magenta and Yellow once overprint is set to true.
  • Note that both DeviceGray and Separation Black do overprint spot colors if overprint is set to true.

a_eq_b_eq_0_is_Black

Keys

  • LabGraph-a_eq_b_eq_0_is_Black
  • LabImage-a_eq_b_eq_0_is_Black

Values

Ignore parameter

Convert as defined for color space Lab (default)

DeviceGray

Use DeviceGray

DeviceCMYK Black

Use DeviceCMYK Black

Separation "Black"

Use Separation Black

Description

If a and b is 0 the luminosity value is directly transferred to the designated color space.
The color conversion engine uses an internal tolerance of 1%, this means the differences between L and a as well as for L and b must be <= 1%.

a_eq_b_eq_0_is_Black_ExcludeBlendModes

Keys

  • LabGraph-a_eq_b_eq_0_is_Black_LimitToBlendModes
  • LabImage-a_eq_b_eq_0_is_Black_LimitToBlendModes

Values

Blend mode Name of Blend modes to exclude from color conversion
To exclude multiple Blend modes, one setting for each blend mode has to be configured

Description

Objects, which are using a Blend mode listed in this parameter, will be processed using the normal color conversion and no preservation of black objects will take place.
This might be appropriate for objects (with empty colorant channels), that are using certain blend mode, which are using these empty channels to achieve a special effect with underlying objects.
If these empty channels would be replaced by a single colorant color space, these effects would not work anymore, so they must be preserved in some certain cases.

Please see article "Processing black objects" for further details.

HandleProcessColorInDeviceN_SeparationAsDeviceCMYK

Keys

  • CMYKGraph-HandleProcessColorInDeviceN_SeparationAsDeviceCMYK
  • CMYKImage-HandleProcessColorInDeviceN_SeparationAsDeviceCMYK

Values

Treat process colors defined in DeviceN or Separation as spot col­ors

Treat process colors defined in DeviceN or Separation as spot col­ors (default)

Treat process colors defined in DeviceN or Separation as DeviceCMYK

Treat process colors defined in DeviceN or Separation as DeviceCMYK

Description

This parameter defines the way process colors (Cyan, Magenta, Yellow, Black) in DeviceN or Separation are treated. If set to On, they are treated as DeviceCMYK objects. Not defined color channels are set to 0% in the respective color. To keep the overprint settings, the original color space (Separation or DeviceN) is recreated after the conversion if possible.

Use the AdvancedColorConversion parameters to define the treat­ment of newly added color channels.

AdvancedColorConversion

Keys

  • CMYKGraph-AdvancedColorConversion
  • CMYKImage-AdvancedColorConversion
  • GrayGraph-AdvancedColorConversion
  • GrayImage-AdvancedColorConversion

Values

No special treatment

Convert as defined for destination color space

Apply dot gain difference

Apply dot gain difference

Description

If set to "No special treatment", tints in colorants that were originally 0 are preserved.
Handles all black objects. Black objects are using only the K channel of CMYK or DeviceGray or Separation Black or DeviceN with only one channel named Black.
If necessary, new channels will be added for DeviceN (Separation color space becomes DeviceN after the conversion). With AdjustDotGain the dot gain difference between source and destination profile is calcuated and all color values are modified so that the dot gain difference is compensated. This is useful mainly for standard PCS conversions.


CompressionMethod

Keys

  • Destination-CompressionMethod

Values

Keep compression method
Keep compression method of origi­nal (default)
Compress all to ZIP
Compress all handled images with ZIP
Compress all to JPEG
Compress all handled images using JPEG

Description

Specifies the method for recompression of converted images.

  • Note: All processed images are decompressed for color conversion tasks. If recompressing with JPEG the quality level is to be defined with the param­eter Destination-JPEGQuality. Please keep in mind that every JPEG compression leads to the loss of quality.

JPEGQuality

Keys

  • Destination-JPEGQuality

Values

Minimum

Minimum JPEG quality compression (20)

Low
Low JPEG quality compression (40)
Medium
Medium JPEG quality compression (60)
High
High JPEG quality compression (80)
Maximum
Maximum JPEG quality compression (100)

Description

Allows for specifying the quality level in which JPEG objects are saved after the conversion.

  • Note: The predefined values are interpreted as a percentage declaration between 0 and 100. The value in brackets are giving a rough comparision to the equivalent setting in Adobe Photoshop.

SetTransparencyBlendSpaceToDest

Keys

  • Destination-SetTransparencyBlendSpaceToDest

Values

Leave unchanged
Leaves transparency blend color space unchanged
Set to destination ICC profile
Sets destination color space as transparency blend color space
Set to destination as device color space
Sets destination color space as transparency blend color space;
if destination color space is ICC based, the respective device color space is set as transparency blend color space
Set to destination if equal to Output Intent
Sets destination color space as transparency blend color space;
if destination color space is ICC based and the output intent matches the destination profile, the respective device color space is set as transparency blend color space

Description

Allows for specifying the transparency blend color space after the color conversion.

Implementation notes

When importing old "Convert colors"-Fixups, the contained Policy file will show up in the "Advanced conversion policy" Pop-Up in the "Destination"-tab.

It is possible to edit the Policy file using the parameters described on this page. You can even select another existing Policy file and export such Fixups

To avoid contradictionary settings, no configuration can be done in the "Advanced settings"-tab in such Fixups.

No matter if the old, deprecated Policy files or the new "Advanced settings" are used in the Fixup, both will work in pdfToolbox 11 and later.

Watch Dietrich von Seggern talk about 'Convert colors: Advanced settings' in the video below:

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