Contrast of tiles and item graphics in "stealth" monochrome

[Freddybear]

Using the "shockbolt" graphic tiles with a stealthy Rogue, I find that some things don't have enough contrast to show up against the tile background in some dungeons. For instance, the escort portal is totally invisble against the ground in the Old Forest when my character is in Stealth. Same for the Angolwen portal on the world map. Ash staves also blend in almost completely.

I don't recall any such problem with the "default" tiles. Mushroom, I think they were called? But it wouldn't hurt to examine the tile sets anyway.