II.B - A few standards for files¶
Here is a list of some standards associated with common files.
Not all the technical possibilities for each type of file are listed here, only the most common (and standard) are indicated.
While these lists are not necessarily official standards, these correspondences are standardized by usage.
Image formats (Jpeg, PNG, TGA, TIFF…)¶
- Space : sRGB
- Pixel format : RGB, Full Range
- Depth :
- Jpeg : 8 bpc
- PNG : 8 bpc, 16 bpc
- TGA : 8 bpc
- TIFF : 8 bpc, 16 bpc1
Hint
It’s possible to see PNG HDR which use the color space Rec.2020.
OpenEXR¶
- Space: RGB linear, but it is also the official format for ACES, or Filmic from Blender. It is the only format that actually allows to store any existing color independently of the color space used to represent it, and therefore the preferred format to work with.
- Pixel format :
- RGB, Full Range
- YUV 4:4:4 or equivalent to YUV 4:2:0 with Luma/Chroma option, Full Range
- Depth :
- 8 bpc
- 16 bpc (integer or float)
- 32 bpc (integer or float)
Hint
The beauty of the EXR is that it can store colors in a floating format instead of the usual integer format, so there is no need to use integer versions of the depth. It is because of this “float” format that the EXR can store any color data without loss: it also stores colors outside the workspace (whose values are greater than 1).
Note
It should actually be understood that the color space in an EXR file doesn’t matter: the file stores raw data, which isn’t “clamped” (values above 1, the theoretical maximum of a color space, are possible); an EXR file can therefore store colors outside the gamut* and of the luminosity* of its color space.
MP4 h.264 / h.265 / AVCHD / HEVC and other HD videos (2K) or UHD (4K)¶
- Space : Rec.709, Rec.2020 possible in UHD and more (4K).
- Pixel format : YUV 4:2:0 ; although 4:2:2 and 4:4:4, even RGB, are possible, they are not very standard and many players will not be able to read them. Limited Range
- Depth :
- 8 bits in Rec.709
- 10 bits in Rec.2020 UHD/4K
- 12 bits in Rec.2020 4K HDR
SWF (and others web formats)¶
- Space : sRGB
- Pixel formats : RGB, Full Range
- Depth : 8 bpc
Be careful, Adobe After Effects (at least some versions), imports it in Rec.709 instead of sRGB. It is then necessary to change the interpretation manually.
QuickTime Animation / RLE¶
- Dpace: Rec.709
- Pixel format : YUV 4:4:4, Full Range
- Depth : 8 bpc
Sources & References
-
The TIFF allows many different color spaces, including CMYK and CIE Lab for example, and also the YUV format in a less standard way. ↩