[Quality] Menu


This section describes each item on the [Image Quality] menu of the SkyPDF V4 MT Driver Settings screen.

Image Quality

Image Compression

The [Image Compression] section allows you to configure settings for the compression of images embedded in PDFs.

Color/Grayscale images compression method

You can specify the compression method for colour images and grayscale images.

None No compression.
  • This is the recommended setting if you need to output a high-quality PDF even if the file size becomes large.
Automatic decision for minimum file size Automatically determines the most efficient compression method from Zip, JPEG, and JPEG2000.
Because automatic determination is performed, memory usage increases and processing slows down.
Zip A compression method suitable for images with a wide range of single colors, combinations of single colors, and patterned images.
The image quality does not deteriorate even if compressed.
JPEG A compression method suitable for continuous tone images such as photos, and large file size images with high resolution.
Compression is accompanied by a deterioration in image quality.
JPEG2000 (Compatible PDF version: 1.5 and later)
An evolution of JPEG, it generates less noise compared to JPEG.
Processing speed is slow, but high compression is possible.
Compression is accompanied by a deterioration in image quality.
Compression Quality Setting when JPEG or JPEG2000 is specified as the compression method.
Specify a value between 1 and 100 %.
The larger the value, the larger the file size, but the less the image quality deteriorates.

Monochrome images compression method

You can set the compression method for monochrome images to be embedded in the PDF.

None No compression.
  • This is the recommended setting if you need to output a high-quality PDF even if the file size becomes large.
Automatic decision for minimum file size Automatically determines the most efficient compression method from Zip, CCITT Group 3, CCITT Group 4, and JBIG2.
Because automatic determination is performed, memory usage increases and processing slows down.
Zip A compression method suitable for images with a wide range of single colors, combinations of single colors, and patterned images.
The image quality does not deteriorate even if compressed.
CCITT Group 3 A general-purpose compression method suitable for monochrome image formats.
The image quality does not deteriorate even if compressed.
CCITT Group 4 A monochrome compression method with a higher compression rate than CCITT Group 3.
The image quality does not deteriorate even if compressed.
JBIG2 A compression method that allows for higher compression than other methods, although processing slows down.
Image quality degradation is accompanied.
  • This setting cannot be set simultaneously with PDF/X.

Down Sampling Mehod

When you set the down sampling method, when embedding images in the PDF, down sampling (reduction of the number of pixels in the image) is performed to the value of Resolution specified.

None No down sampling.
  • This is the recommended setting if you need to output a high-resolution PDF.
Bilinear An interpolation method that prioritizes print speed over print quality.
The amount of data decreases and the processing speed increases.
It is suitable for simple images and shapes.
  • This setting cannot be set simultaneously with PDF/X.
Bicubic An interpolation method that balances print speed and quality.
Compared to bilinear, the amount of data increases and the processing speed slows down, but a smoother gradation image can be obtained.
It is suitable for complex images and photos.
  • This setting cannot be set simultaneously with PDF/X.
Lanczos An interpolation method that prioritizes print quality.
Compared to bicubic, the processing speed slows down, but interpolation is smoother.
  • This setting cannot be set simultaneously with PDF/X.
Resolution Specify the number of pixels per inch between 72 and 2400 dpi.
If the image to be embedded in the PDF is higher than the resolution specified here, down sampling is performed by the specified method.

File Size

PDF Object Compression

Compression Types By specifying the type of compression, compression of PDF objects other than images is performed.
Compressing reduces the file size.
However, it is necessary to update the PDF version.
None No compression.
Compress the structure information (Compatible PDF version: 1.5 and later)
Compresses by converting the cross-reference table into a cross-reference stream.
Object Compression (Compatible PDF version: 1.5 and later)
Converts the cross-reference table into a cross-reference stream and, in addition, some PDF objects into an object stream.
Compress PDF contents Compresses the contents of the PDF.
When compressed, the file size becomes smaller, and the drawing instructions describing the page contents are black-boxed.
Encode PDF stream as ASCII type Normally, a stream object that becomes binary data is encoded with ASCII85.
Compared to binary data, the file size becomes larger.