4 ms·
It's great you listen. So I'll try. 1. Scaling down in linear colorspace is essential. One example is [1], where [2] is sRGB and [3] is linear. There are some
by vladdanilov 10y ago
It's great you listen. So I'll try.
1. Scaling down in linear colorspace is essential. One example is [1], where [2] is sRGB and [3] is linear. There are some canary images too [4].
2. Plain bicubic filtering is not good anymore. EWA (Elliptical Weighted Averaging) filtering by Nicolas Robidoux produces much better results [5].
3. Using default JPEG quantization tables at quality 75 is not good anymore. That's what people referring as horrible compression. MozJPEG [6] is a much better alternative. With edge detection and quality assessment, it's even better.
4. You have to realize that 8-bit wide-gamut photographs will show noticeable banding on sRGB devices. Here's my attempt [7] to reveal the issue using sRGB as a wider gamut colorspace.
[1] https://unsplash.com/photos/UyUvM0xcqMA https://unsplash.com/photos/UyUvM0xcqMA
[2] https://cloud.githubusercontent.com/assets/107935/13997633/a30d90a2-f0f8-11e5-8705-9e603a00e1a0.png https://cloud.githubusercontent.com/assets/107935/13997633/a...
[3] https://cloud.githubusercontent.com/assets/107935/13997660/bd07d116-f0f8-11e5-98d8-dab05f40b220.png https://cloud.githubusercontent.com/assets/107935/13997660/b...
[4] https://cloud.githubusercontent.com/assets/72159/11488537/3da372b4-97bf-11e5-93d1-7b0923a0a973.png https://cloud.githubusercontent.com/assets/72159/11488537/3d...
[5] http://www.imagemagick.org/Usage/filter/nicolas/ http://www.imagemagick.org/Usage/filter/nicolas/
[6] https://github.com/mozilla/mozjpeg https://github.com/mozilla/mozjpeg
[7] https://twitter.com/vmdanilov/status/745321798309412865 https://twitter.com/vmdanilov/status/745321798309412865
- unhammer 10y agoI thought there was something familiar about that name Robidoux … I see he's the same one that got some crowdfounded work on GIMP's new scaling methods: http://libregraphicsworld.org/blog/entry/advanced-samplers-for-gegl-to-be-crowdfunded http://libregraphicsworld.org/blog/entry/advanced-samplers-f...