@Lambda_Labs The game actually uses IMAGE_DEPTH_EXTEND_MONO_SEAMLESS and IMAGE_DEPTH_EXTEND_SEAMLESS (bottom-middle and bottom-right sprites in this sheet) to render the Prophecy Panes throughout Chapter 4's dark world (source: Deltarune's decompiled source code says so).

@skrakkat I have done some digging into the rendering code of the game, and can confirm the game does a lot of dynamic filtering and rendering to get the prophecy panes we all know and love. The only reason I looked through the code this deeply was to recreate the effect myself in CSS for an animated version of my profile pic on my website (Coming Soon™, as of writing). Can you tell I really like this effect? Anyways, fair warning, this will get technical (even though this is the abridged version), but here goes:

The game uses IMAGE_DEPTH_EXTEND_MONO_SEAMLESS to render symbols and text on the prophecy panes, with the following filters in this order: multiply all pixels with the hex colour #42D0FF (defined as "propblue" in the game code), then multiply all pixels in the resulting sprite by three to give that "oversaturated blue" look, then mask the unused area with one of the spr_dw_church_prophecy_*_icon sprites (depending on the actual prophecy being shown), and finally render a few times at different locations and transparencies. The text version uses the same sprite, but different filter (this game files has its own object just for rendering the prophecy text). I haven't quite finished figuring it out yet, but I was able to create a pre-computed sprite that looks pretty accurate (if only I'd kept the CSS code that I used to make it...)

IMAGE_DEPTH_EXTEND_SEAMLESS is used for the background, and only has one filter (a continuously changing colour ranging between #8BE9EF and #17EDFF) before being rendered over the top of the prophecy icon (yes, you read that right - it's just only noticeable on dark-blue portions of the icon), and also behind everything with a gradient fade.

The actual rendering code for everything put together is quite a bit more complex than that, but that's the gist of it.

Idk why, but thats give me a sense of 2000s nostalgia...

its the top two with weird layering effects done in-engine

@skrakkat Unsure, that's the whole reason I made this sheet but I couldn't find it looking through the sprites. I may have to look again sometime...

Where's the one for the Prophecy excerpts in Chapter 4?

"image_depth" is literally the background for the vessel creation sequence