Can someone recommend settings?

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Tec4
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Joined: Wed Aug 30, 2017 9:51 pm

Can someone recommend settings?

Post by Tec4 »

I am trying to reduce the size of a cbz file by cracking it and then reducing the size of the jpegs inside. However, sometimes when I try to shrink the images they end up larger. For instance I set them to reduce to 50% of the original size using Lanczos but they end up being twice as large. So a jpeg that is 4MB in size will end up being 8MB in size after resizing.

Are there settings I can use that will result in a 50% exact reduction in size of all images when I set resize to 50%? Or am I missing something? I would like to reduce a jpeg from 4MB to 2MB without losing much in the way of image quality.
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XnTriq
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Re: Can someone recommend settings?

Post by XnTriq »

Welcome aboard, Tec4.

Could you please upload a sample to a free file sharing host like Wikisend? (The forum's maximum attachment size is 2 MiB.)
Tec4
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Re: Can someone recommend settings?

Post by Tec4 »

Thanks, I enjoy using the app. Do you want a sample of the resized image?
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XnTriq
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Re: Can someone recommend settings?

Post by XnTriq »

Tec4 wrote:Do you want a sample of the resized image?
Sorry, I should've been more clear: I'd like to do some tests on one of the 4MB originals so I can hopefully give you the best JPEG compression settings for your use case.
Tec4
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Joined: Wed Aug 30, 2017 9:51 pm

Re: Can someone recommend settings?

Post by Tec4 »

Couldn't get wikisend to work but here is a zippyshare file:

http://www55.zippyshare.com/v/XWezsmY4/file.html
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XnTriq
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Re: Can someone recommend settings?

Post by XnTriq »

Thanks for the sample. Please try the following settings:
144849_1.png
144849_2.png
144849_3.jpg
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Tec4
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Joined: Wed Aug 30, 2017 9:51 pm

Re: Can someone recommend settings?

Post by Tec4 »

Wow that worked nicely. Although it ended up smaller than 50%. But smaller is actually better so I'll take it. Thank you!
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XnTriq
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Re: Can someone recommend settings?

Post by XnTriq »

Tec4 wrote:Although it ended up smaller than 50%. But smaller is actually better so I'll take it.
Here are the geeky stats in case you're interested ;-)
  • Original Result
    • Dimensions: 1988×1528 pixels (50%)
    • Chroma subsampling: 4:4:4 (1×1,1×1,1×1)
    • Quality factor: 90
    • File size: 1'301'058 bytes
Tec4
Posts: 5
Joined: Wed Aug 30, 2017 9:51 pm

Re: Can someone recommend settings?

Post by Tec4 »

Interesting...thank you.