I have some good news!
First of all, I have just finished introducing the RCD demosaicing into photoflow. The implementation is based on the RT version, adapted to process small image tiles in parallel.
Moreover, and following what @agriggio has reported, I have modified the RAW data clipping behaviour in photoflow, which results in much lower purple fringing around dark objects on clipped backgrounds. The improvement is visible for all demosaicing methods, but only when the highlights reconstruction is set to clip (which is the default mode).
The new logic is the following:
- when the highlight reconstruction is set to clip, the WB multipliers are scaled such that the lowest one has a value of 1. The RAW values are then multiplied by the WB coefficients and then clipped to the [0…1] range.
- when the highlights reconstruction is set to blend or none, the WB multipliers are scaled such that the highest one has a value of 1. The RAW values are then multiplied by the WB coefficients, without being clipped. After the demosaicing, and before the conversion to the working colorspace, the RGB values are then scaled by the ratio between the highest and lowest WB coefficient, so that the image brightness is the same as in clip mode.
Note that in all cases the demosaicing is performed after converting the RAW data to the user-chosen WB.
Here is a comparison between the Amaze output with HL reco set either to clip and blend (which corresponds also to the old clip mode as long as purple fringing is concerned):
Amaze, blend mode:
Amaze, clip mode:
Finally, here is the output of the RCD demosaicing in clip mode:
There is a slight difference between the two demosaicing methods, but not really a striking one…
Second, I have added a curve representation for the tone mapping functions, which should ease the tweaking of parameters. The curves are represented in perceptual encoding, to better visualise the effect in dark areas. Here is a screenshot showing the filmic new curve with default parameters:
Updated packages are available as usual from here.