Update filmic-rgb.md #742
Update filmic-rgb.md #742
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Updated references to changed defaults and changed the structure to the mid tone saturation controls to emphasize the newer v6 and 7 versions
| @@ -212,19 +212,19 @@ hardness (previously _target power factor function_) | |||
| : This parameter is the power function applied to the output transfer function, and it is often improperly called the _gamma_ (which can mean too many things in imaging applications, so we should stop using that term). It is used to raise or compress the mid-tones to account for display non-linearities or to avoid quantization artifacts when encoding in 8 bit file formats. This is a common operation when applying ICC color profiles (except for linear RGB spaces, like Rec. 709 or Rec. 2020, which have a linear “gamma” of 1.0). However, at the output of _filmic rgb_, the signal is logarithmically encoded, which is not something ICC color profiles know to handle. As a consequence, if we let them apply a gamma of 1/2.2 on top, it will result in a double-up, which would cause the middle-gray to be remapped to 76% instead of 45% as it should in display-referred space. | |||
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| latitude | |||
| : The latitude is the range between the two nodes enclosing the central linear portion of the curve, expressed as a percentage of the dynamic range defined in the [_scene_](#scene) tab (white relative exposure minus black relative exposure). It is the luminance range that is remapped in priority, and it is remapped to the luminance interval defined by the contrast parameter. It is usually advisable to keep the latitude as large as possible, while avoiding clipping. If clipping is observed, you can compensate by either decreasing the latitude, shifting the latitude interval with the _shadow ↔ highlights balance_ parameter, or decreasing the contrast. | |||
| : The latitude is the range between the two nodes enclosing the central linear portion of the curve, expressed as a percentage of the dynamic range defined in the [_scene_](#scene) tab (white relative exposure minus black relative exposure). It is the luminance range that is remapped in priority, and it is remapped to the luminance interval defined by the contrast parameter. While it is set to 0 by default, it is usually advisable to keep the latitude as large as possible, while avoiding clipping. If clipping is observed, you can compensate by either decreasing the latitude, shifting the latitude interval with the _shadow ↔ highlights balance_ parameter, or decreasing the contrast. | |||
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I've not reviewed all of the text in the PR but this paragraph is the reason I haven't resolved that issue so far. The recommendation (keep the latitude large) comes from the original developer. But since he is also the person who changed the default value to 0, it's hard to justify keeping that recommendation. Unfortunately since he's stopped talking to anyone involved in darktable now, it's hard to resolve this contradiction or understand his reasoning for the change.
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Maybe the least worst option might be to just remove reference to the recommendation altogether
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I don't know if this is a contradiction. I believe it makes sense to set the latitude as wide a possible to control the roll-off at the edges, but the default is set at zero so the user can decide the settings to use. At least, that's how I see it. Personally, I don't bother with latitude, so I'm ok with the change or to remove that discussion altogether.
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This is in response to Document recent changes to filmic defaults, #527
I updated references to changed defaults and changed the structure to the mid tone saturation controls to emphasize the newer v6 and 7 versions
This is my first attempt at a Pull Request, so hopefully I did this correctly.