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Thread: change image bpp

  1. #1

    Default change image bpp

    is it possible to convert the image and lower its bpp?

  2. #2
    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    Command line options can be found in i_options.txt in the Program Files folder.

    /bpp=BitsPerPixel - change color depth of the input image to BitsPerPixel

    Example for /bpp:
    i_view32.exe c:\test.jpg /bpp=8
    Supported BPP-values: 1, 4, 8 and 24 (decrease/increase color depth)
    => Open 'c:\test.jpg' and reduce to 256 colors

  3. #3

    Default

    Quote Originally Posted by Bhikkhu Pesala View Post
    Command line options can be found in i_options.txt in the Program Files folder.

    /bpp=BitsPerPixel - change color depth of the input image to BitsPerPixel

    Example for /bpp:
    i_view32.exe c:\test.jpg /bpp=8
    Supported BPP-values: 1, 4, 8 and 24 (decrease/increase color depth)
    => Open 'c:\test.jpg' and reduce to 256 colors
    but im using iview64 *path* /convert *to path* / bpp = 1
    the image still 8bpp

  4. #4
    Professional User Mij's Avatar
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    You do not say why you want to reduce the image to 1 bpp. I use it to save scanned images as PDF files with small file size but because I want to apply saturation, contrast and brightness adjustments before reducing to 2 colours, I use the /advancedbatch command line option. The images are forms with handwritten entries and I get nice clear 1 bpp black and white images from a range of different coloured inks and line widths.

    I use 32bit Irfanview to do this using the old IMPDF.DLL plugin to save the files. This could not be done with the 64bit Irfanview plugin at the time I set it up. I do not know if it is possible now. One thing that confused me at first was that if I tried to view the 1bpp PDF images in Irfanview they were always opened and displayed as 24bpp but I could tell from the file size that they were genuine 1bpp images that I was opening. I now always view them in a PDF program instead.

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