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Why red color looses details most in jpeg compression



  • Stephen Doyle

    Hi Abhishek,
    I can see you contacted our support team about this also, so I'll follow up on the request that you created.
    We can share the recommended solutions here also when we've assisted with the support request

  • Benjamin Sutton

    Stephen - Wondering if you can share those details with us as well? Trying to find some resources on the compression of images uploaded. Thanks!

  • Stephen Doyle

    Hi Benjamiin,

    Apologies; this wasn't followed up on here because the original poster didn't reply to give us the specific images they were asking about so we could check the details and see if there was any issue.

    I did send them some general info, which I've pasted below in case that's helpful (and I've updated the original links I provided to be links to documentation that was added after May 2020 when I replied to this originally)

    If you have any issues with specific images in your account, I recommend creating a support request for my team directly and we can check it for you.


    To give some general answers, you may see better results using our automatic quality feature (with q_auto:good or q_auto:best) than with a fixed quality level, partially due to chroma subsampling, and also because our algorithm will analyse the output and check for visual changes in that output.

    There's a description of how this works here:

    You may also be seeing that the color profile from the original image has changed, and if so, you can force a specific profile via the 'cs' parameter:

    Thirdly, if the original is JPEG also, you're compressing an already-compressed image and that will lose some information compared to the first time compression is introduced. If so, we recommend that you upload the original file in a lossless format like TIF, PNG, PSD, etc, and then deliver it in JPEG, WEBP, [edit: AVIF etc,] preferably via our automatic format selection:


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