Meaning of "Wandelbild" in old book

Question

I was reading a short story called "Die Drei Schwestern" by Richard Dehmel, published in 1893, and came across this sentence:

Und so — ja — schritten sie davon — in den brennenden Abendhimmel hinein — schattenhaft schwarz wie ein Wandelbild — bis der Wald sie verschlang.

The context is that the narrator had been accommodating two people, Heinz and Marie, on his family's estate and now the two have gotten engaged and are leaving to live on Heinz's estate. I'm confused about the meaning of this word "Wandelbild." The DWB has the definition "durch einen projectionsapparat hervorgerufene wechselnde bilder, besonders farbenspiele" which is difficult to make sense of. It also has:

auch ein am bühnenhintergrund vorbeigezogenes, die verwandlung der scene andeutendes bild kann man so nennen; bei Campe verdeutschungswb. 108ᵇ wird wandelbild für anamorphose, ein bild (caricatur), das von vorn und von beiden seiten angesehen, drei ganz verschiedene gegenstände darstellt, vorgeschlagen

I looked up the cited book "Verdeutschungswörterbuch" by Joachim Heinrich Campe and accidentally found a different book of the same title by Daniel Sanders, published in 1884, where "Wandelbild" is given as an alternative German term for the more foreign word "Kaleidoskop," which seems to clarify the DWB's first definition. Still, I don't know how any of these meanings make sense in the context of the sentence. I did find a video of a kaleidoscope which shows some dark shapes floating around in the field of view; maybe the author is comparing those shapes to the silhouettes of Heinz and Marie? This seems far-fetched, but I don't know how many kaleidoscopes produced at this time contained those dark floating shapes.

There's also the German wikipedia page for the Isenheim Altarpiece, which is a "winged altarpiece"—a kind of painting that can be folded in different ways to reveal different paintings. The page describes the piece as a "Wandelaltar" with different "Wandelbilder." Still, I can't figure out how this would make sense in context. Maybe I'm missing something.

Answer 1

Apparently, "Wandelbild" is a compound "Wandel" + "Bild", literally "change/transformation" + "picture". German is fond of this type of compound and they are often composed for a single use in a specific context. But in this case it seems to refer a particular type of picture or artwork that would be familiar to people from the 19th century but apparently not so much for people from the 21st century. From context I think we can infer that it's a picture that changes in some way. One example is this picture which changes depending on the angle you look at it (Annunciation if viewed from the left, and Madonna if viewed from the right). There are also examples of pictures which seem to change when turned upside down (for example this caricature). Ambiguous images such as My Wife and My Mother-in-Law would have been known at the time as well.

So I think the impression the author was going for was that the couple disappeared as if they were only an optical illusion of some kind. The entire passage is very figurative and there are several parts that aren't meant to be taken literally: The forest does not literally "swallow them", and they don't actually walk "into the sky" which was not actually "burning". Given that, the author seems to have been going for an impression instead of a literal meaning. I don't know what "change-picture" type the author was referring to specifically, but I don't think it really makes a difference since it's meant to be symbolic. I do think we can rule out a kaleidoscope though.

Answer 2

There are some uses of the word Wandelbild, but they apply to different subjects, among them moving pictures as seen in a dream (pre-cinema era). The problem with compound nouns is, that they leave some freedom of choice:

• The picture itself might may change
• The appearance may change, by look differently from different angles
• The picture might be exchanged easily, e. g. swapped by another backdrop picture.

But in the context given, neither choice appears striking, so I am guessing that Schattenbild or Schattentheater (see Wikipedia) might lead closer to the intended meaning for a contemporary reader: Here some silhouette shapes are projected from behind onto a given "screen" (may also be a picture, if sufficiently translucent), by moving those mentioned shapes some change is performed, and also shadows are present.