ART: Demosaicing and red color (of Ricoh GR)

The choice of demosaicing algorithm can affect the red color of small areas. I noticed this in ART with Ricoh GR DNG files.

For example, one fragment and different algorithms (see 1 and 2).

Fast, AMaZE, RCD, LMMSE, VGN4 (300%):

This local red is more saturated with Fast and, unexpectedly, with AMaZE, but worse with the other algorithms.

And even when using the "False Color Suppression Steps" (FCSS) option (value 1 or higher) with AMaZE, the red loses saturation.

FCSS=0 and FCSS=1 (300%):

Considering that the Ricoh GR is prone to moiré, this makes processing more complex because FCSS is not suitable for all images. A solution would be to use a sensor with a larger number of pixels.

See also related notes:

• RawTherapee (2022) и ART (2022-03-30)
• RawTherapee 4.0.10.36 и новые алгоритмы дебайеризации (2013-04-10)
• RawTherapee 3.0.0 (алгоритмы дебайеризации) (2011-07-31)

Image albums:

• Photo