One look at the walls tells you that a brooding atmosphere of Lovecraftian horror isn't going to thrive here:
Painting over them or otherwise leaving permanent marks is not an option, but neither is having bright yellow walls in Keziah Mason's former residence.
The solution we came up with was to create artificial walls over the real walls, using boards of foam insulation.
From Home Depot we procured several 4'x8'x1/2" foam boards:
To give the walls a properly grungy old look, we started with a base coat of yellowish off-white ("Sea Sponge") and then
used brushes to smear watered-down brown and green ("Landslide" and "Dark Cavern") paint over it. For a bit of extra
texture we also used a soldering iron to carve things into it, by and large intended to convey something of Gilman's
mathematical research, exposure to the Old Ones mythos, and increasing insanity.
Measuring the hallway, it turned out we'd need close to 20 of these things to cover the area we wanted to decorate.
We'd also need to carve around things like lights, fire extinguishers, and doors, so we drew a scale map of the area for
Fortunately, foam cuts cleanly and quickly with a bit of applied heat, so the carving wasn't going to be a
problem. Early experiments with a serrated knife resulted in lots of crumbly foam bits all over the floor; I can't
recommend the "hot wire" method highly enough to anyone working with foam.
Once the base coats of paint were on the cut pieces, they had to be decorated, in order to really emphasize the atmosphere of the space. A mixture of mathematical formulae, Mythos text excerpts, and journal entries written from the point of view of Walter Gilman were painted onto the walls with acrylics; this was a labor-intensive process but ultimately worth it.
With this done, the final step was to affix them to the walls with painter's tape. The final result is pleasantly creepy.
Next: Brown Jenkin