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):
- RenderingIntent
- C_eq_M_eq_Y_is_Black
- C_eq_M_eq_Y_is_Black_ExcludeBlendModes
- R_eq_G_eq_B_is_Black
- R_eq_G_eq_B_is_Black_tolerance
- R_eq_G_eq_B_is_Black_ExcludeBlendModes
- SetGrayColorSpaceTo
- a_eq_b_eq_0_is_Black
- a_eq_b_eq_0_is_Black_ExcludeBlendModes
- HandleProcessColorInDeviceN_SeparationAsDeviceCMYK
- AdvancedColorConversion
- CompressionMethod
- JPEGQuality
- SetTransparencyBlendSpaceToDest
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_tolerance
Keys
- RGBGraph-R_eq_G_eq_B_is_Black_tolerance_light
- RGBImage-R_eq_G_eq_B_is_Black_tolerance_light
- RGBGraph-R_eq_G_eq_B_is_Black_tolerance_mid
- RGBImage-R_eq_G_eq_B_is_Black_tolerance_mid
- RGBGraph-R_eq_G_eq_B_is_Black_tolerance_dark
- RGBImage-R_eq_G_eq_B_is_Black_tolerance_dark
Values
<List of availible tolerance values> | Tolerance values between R and G, G and B and R and B interpreted as percentage points: +/- 0%, +/- 0.5%, +/- 1%, +/- 1.5%, +/- 2%, +/- 2.5%, +/- 3%, +/- 3.5%, +/- 4%, +/- 4.5%, +/- 5% |
Description
These settings can be used for an improved and more controlled color conversion of gray RGB images or graphs to CMYK by allowing you to set individual tolerances to specify which RGB values should be considered neutral gray and which should not.
Because color differences are easier to see in lighter shades of RGB gray than in darker shades, separate tolerances can be set for light (0-20%), mid (40-60%), and dark (80-100%) shades. Everything in between will be interpolated. RGB grays below the tolerance are converted to separation black (100% K only), while RGB grays above the tolerance are converted to CMYK to preserve color representation.
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: