For the function to perform as intended, the following requirements must be met:

• The PDF file contains color, grayscale, and/or black-and-white images.
• The PDF file contains images with a resolution lower than the resolution entered in the Option For Resolution less than [4] | [8].

Figure 1: The dialog of the Fixup Upscale Image Resolution

Choose from the following options to upscale the image resolution:

• Templates [1] – settings selected in the dialog can be saved as a template and thus applied to other Articles or Print Items and used in the Fixup operation.

Color/Grayscale images

• Resample [2] – select the method for Resample here. The following options are available:
  • Bicubic – Bicubic Resampling calculates the average of the pixels that should be added. When calculating the average, the value around the color value of the surrounding pixels is included. When upscaling the resolution, this method leads to smoother tonal gradations.
  • Average Resample – the Average Resampling also calculates the average value of the pixel. The color value of the surrounding pixels is not considered when determining the average value.
  • Lanczos – is a complex type of Resampling that, depending on the Print Item, usually leads to better results than those obtained with Bicubic Resampling.
  • BlackmanSinc – is a complex type of Resampling that, depending on the Print Item, typically yields better results than those obtained with Bicubic Downsampling.
  • No Downsampling  – no Downsampling of the Image Resolution is performed.
  • Variable Content [10] – select the desired placeholder – database field or user-defined field – from which the value for selecting the recalculation method should be retrieved. The following values must be present in the selected field for the selection to be generated:
    • BicDownsampling
    • AvgDownsampling
    • LanczosDownsampling
    • BlackmanSincDownsampling
    • Off
• Recalculate to [3] – enter the desired resolution in dpi for the grayscale or color image after upscaling. For Variable Content [11], select the desired placeholder – database field or user-defined field – from which the value for the target resolution should be retrieved.
• For Resolution less than [4] – enter the minimum resolution in dpi for images that should be resized. For Variable Content [12], select the desired placeholder – database field or user-defined field – from which the value for the minimum resolution of the image to be resized should be retrieved.
• Compression [5] – use the drop-down menu to select the compression method to apply to the upsampled images. The following options are available:
  • Unchanged – the existing compression method of the image is reused.
  • Lossy (JPEG) – the upsampled images are compressed using the JPEG algorithm.
  • Lossless (ZIP) – the upsampled images are compressed lossless using the ZIP algorithm.
  • Variable Content [13] – select the desired placeholder – database field or user-defined-field – from which the value for selecting the compression method should be retrieved. The following values must be present in the selected field for the selection to be generated:
    • RetainExisting
    • JPEG
    • ZIP

Figure 2: Left: Values found in the selected field for the Option Resample; Right: Values found in the selected field for the Option Compression

Monochrome Images

• Resample [6] –  select the Resample method here. The following options are available:
  • Bicubic – during Bicubic Resampling, the mean value of the added pixel is calculated, incorporating the color values of the surrounding pixels. If the mean value exceeds 50%, a white pixel is generated; if it is below, a black pixel is generated.
  • Average Resample – with Average Resampling, the average value of the pixel is calculated. In this case, the color value of the surrounding pixels are not considered when determining the average value. If the average value exceeds 50%, a white pixel is generated; if it is below, a black pixel is generated.
  • Lanczos – a complex type of Resampling that, depending on the Print Item, usually leads to better results than Bicubic Resampling.
  • BlackmanSinc – a complex type of Resampling that, depending on the Print Item, typically yields to better results than Bicubic Resampling.
  • No Downsampling – no Resampling of the Image Resolution is performed.
  • Variable Content [14] – select the desired placeholder – database field or custom field – from which the value for selecting the Resampling type should be retrieved. The following values must be found in the selected field to generate the selection:
    • AvgDownsampling
    • BicDownsampling
    • LanczosDownsampling
    • BlackmanSincDownsampling
    • Off
• Recalculate to [7] – enter the desired resolution in dpi for the black-and-white image after upsampling. For Variable Content [15], select the desired placeholder – database field or user-defined field – from which the value for the resolution of the target file should be retrieved.
• For Resolution less than [8] – enter the Image Resolution in dpi that should be affected by the extrapolation. For Variable Content [16], select the desired placeholder – database field or user-defined field – from which the value for the target resolution should be retrieved.
• Compression [9] – use the drop-down menu to select the compression method to apply to the upscaled images. The following options are available:
  • Unchanged – the existing compression method of the image is reused.
  • CCITT Group 4  – CCITT Group 4 is a lossless symmetrical and non-adaptive compression method.
  • JBIG – JBIG encoding is a lossy and lossless compression method that has been an integral part of PDF since PDF 1.4.
  • Variable Content [17] – select the desired placeholder – database field or user-defined field – from which the value for selecting the compression type should be retrieved. The following values must be present in the selected field for the selection to be generated:
  • RetainExisting
  • CCITTG4
  • JBIG2

Figure 3: Left: Values found in the selected field for the Option Resample; Right: Values found in the selected field for the Option Compression

To experiment with this function, please refer to the example file Sample_Upsampling.pdf. The image has a size of 250.12 x 166.51 mm and a resolution of 72 dpi.

After the Fixup was applied and the file Sample_Upsampling_End.pdf was created, the image was upsampled to 300 dpi using the values from Figure 1.

Figure 4: Left: Original file with an Image Resolution of 72 dpi; Right: Revised file with an Image Resolution of 300 dpi

Article update: Workflow 1.20.0  03/2025