Others will likely recommend using vastly lower Quality Factors. I like to use not less than a QF=98%, or QF=95% minimum. Using Quantization data compression will reduce fine details fairly rapidly. Second Choice: Reduce Quality Factor from 100%. This will reduce image-file byte-size by around 25% without having very much impact on fine-detail (which is primarily luminance). Set DCT Method to Float (Best but slowest), Smoothing Factor=0, check "Optimize Huffman table":įirst Choice: Setting Croma Sub-sampling from none (1x1) to maximum (2x2, reduces chroma resolution by a factor of 2 in the vertical as well as horizontal axis). It will tell you the exact byte-size of the JPEG in advance (given the settings used).
#Xnconvert best jpeg settings full
Unless you image editor gives you knowledge and full control over Chroma Sub-sampling settings and Quality Factor, export from the image-editor to BMP or TIFF (if alpha channels exist), and use the free, stable, and non-invasive XnView's (for Windows only) excellent JPEG encoder (Tools - Export). The re-encoding of JPEGs from the loss-less format that image-editors use will add additional JPEG encoding artifacts (over and above those that exist from the original JPEG encoding).ĭo not reduce color depth from 24 bits (8 bits per RGB color channel). Depends upon the image-file byte-size that you desire (given anticipated downloading speeds, etc.), the amount of fine-details in the image, the intended viewing size(s). If I edit the JPEG and then export to JPEG, there will be increased artifacts for the size than if I used RAW and then JPEG, no? Kind of like how MP3s encoded from MP3's suffer from artifacts. I'm thinking maybe reducing color depth from 24 bit to maybe 12 bit might help.
Beyond a simple resolution shrink, what methods exist that compress JPEG's well for web-use?
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