There is a separation of the R, G, and B components in an order similar to that found for the nacreous cloud and The Scream sections.
The analysis here seems to support the notion that the sky in The Scream contains clouds and that the change in color component brightness with elevation, as well as the relative change, are more similar to that found in nacreous cloud photographs.
Another photograph analyzed contains both a red nonvolcanic sunset and a nacreous cloud display.
The color analysis presented attempts to add some quantitative assessment of the color patterns and spectral content of The Scream compared with photographs of volcanic sunsets, nonvolcanic sunsets, and nacreous clouds. While we readily admit that the interpretation of color in art and in photographs is problematic, there are at least indications that the color variations and order of the RGB color components in The Scream better match those of a nacreous cloud display than a cloudless volcanic sunset.
(c),(d) As in (a),(b), but through a vertical section of a nacreous cloud photograph.
(a) Variation of the mean and standard deviation of the RGB color components for a 20-pixel-wide vertical transect through the central part of a section of the photograph shown in (b) for a nonvolcanic sunset, (c) Variation of the mean and standard deviation of the RGB color components for a 20-pixel-wide vertical transect through the central part of a section of the photograph shown in (d) for a nonvolcanic sunset and a nacreous cloud display at higher elevation.
It has been suggested that the dramatic red-colored sky was inspired by a volcanic sunset seen by Munch after the Krakatau eruption in 1883 and by a sighting of stratospheric nacreous clouds, and also that it is part of the artist's expression of a scream from nature.
(2017) have hypothesized that the sky in The Scream has a striking similarity to mother-of-pearl or nacreous clouds. They discuss anecdotal evidence concerning the possibility that Munch observed these clouds while out walking with friends one evening, or perhaps on another occasion or occasions.
Nacreous clouds fit this description well, as we shall see later.
This argues against the interpretation that he is depicting nacreous clouds, at least in these later images.