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Getting Started:
    1. Windows
  Text Menu
  (now with video!)
  2. Linux
  Env vars
  3. Mac OSX
  4. Help in other languages

FAQ | Forum

Customizing K2PDFOPT:
    1. K2pdfopt GUIs
    2. Disabling the Windows GUI
    3. The interactive menu
    4. List of command-line options
    5. Using a shortcut
  (now with video!)
  6. Using the K2PDFOPT environment variable
  7. Using the command line

Adjusting the output:
    1. Screen Size
    2. Increasing the magnification
    3. Landscape mode
    4. Output File Size
    5. Setting Margins
    6. Color Output
    7. Uneven Line Breaks/ Excess Margins

Processing Options:
    1. Showing Markings
    2. OCR
    3. Native PDF
  (now with video!)
    4. Auto-Straightening
    5. Ignoring Borders/ Headers/Footers
    6. Detecting Columns
    7. Protecting Regions
    8. Column Order
    9. Right-to-Left Page Scanning
    10. Using Ghostscript
If you would like to reduce the output PDF file size, you can use the -bpc option to reduce the number of bits per color plane. The default is 4 (for 16 graylevels--the same as the kindle can display), but using -bpc 2 will reduce to 4 graylevels and reduce the PDF file size to approximately half. You can even use -bpc 1 to reduce to monochrome output and cut the PDF file size to about one quarter of the default. If your document has only text and no images, and if file size is important, this may be a good option. Or you can try using the -jpeg command-line option with a low quality setting, e.g. -jpeg 50 (see below for how to use customized command-line options). The lower the quality value, the smaller the output file will be, but at the expense of image quality.

See the examples below for how these options affect the output file. The images are crops from page 2 of the k2pdfopt output from this file. The file was converted with -p 2 (just page 2) and -m 0 because it has such small margins. The size of page 2 in the original file, for reference, is 285 kiB.

-bpc option with dithering on (default).

-bpc 8
pdf size=331,099
-bpc 4 (default)
pdf size=159,023
-bpc 2
pdf size=80,162
-bpc 1
pdf size=45,578

-bpc option with -d- (no dithering).

-bpc 8 -d-
pdf size=331,099
-bpc 4 -d-
pdf size=152,173
-bpc 2 -d-
pdf size=74,459
-bpc 1 -d-
pdf size=37,802

-bpc and -c (full color) option with dithering on (default).

-c -bpc 8
pdf size=842,485
-c -bpc 4
pdf size=315,123
-c -bpc 2
pdf size=140,724
-c -bpc 1
pdf size=76,069

-bpc and -c (full color) with -d- (no dithering).

-c -bpc 8 -d-
pdf size=842,485
-c -bpc 4 -d-
pdf size=300,848
-c -bpc 2 -d-
pdf size=127,293
-c -bpc 1 -d-
pdf size=63,400

-jpeg option.

-jpeg 90
pdf size=368,639
-jpeg 70
pdf size=244,984
-jpeg 40
pdf size=173,494
-jpeg 10
pdf size=82,532

The -png, -bpc, -d, and -jpeg options can also be set by selecting Option 'b' (Bitmap encoding) in the k2pdfopt interactive settings menu.


This page last modified
Sunday, 28-May-2017 10:09:24 PDT