Support: The support is a medium-weight, plain-weave, commercially primed linen canvas with a thin, protein-based sizing and a moderately thin, chalk, barium sulfate, lead-white, and zinc-in-oil priming. Warps are slightly smaller in diameter than wefts, with the canvas stretched with the warps in the horizontal orientation. The thread count for the warps is approximately 44 threads per inch and 40 threads per inch for the weft. The work may have been historically removed from an original stretcher and re-stretched on a keyable mortise-and-tenon stretcher. All the stretcher bars have keyable, mortise-and-tenon, mitered ends. All keys are extant and taped to prevent loosening in transit. The center horizontal direction of the painting is drawn in by the stretching to a noticeably smaller dimension. The present tacks are adjacent to, but generally outside of, the original tack holes. The outside of the tacking edge was apparently covered with a black vinyl electrical tape at some previous time, as black adhesive residue remains on all four edges. The canvas is moderately taut. The canvas extended onto the back of the stretcher on all four sides, where it has been trimmed to different lengths. The right edge of the canvas is the roll selvedge, which is unsized and unprimed raw linen fabric. The artist's stretching or the subsequent secondary stretching resulted in regular cusping across all four sides.

Ground or Support Preparation: The processed linen canvas has a commercially applied primer consisting of roughly equal parts calcium carbonate and barium sulfate with trace amounts of 2PbCO3•Pb(OH)2) and ZnO, all in oil, characterized using x-ray fluorescence spectroscopy at 15kV, 33 and 40kV and 28.8, 18 and 3.8 μA under full vacuum.

Design Layers: The graphite underdrawing is occasionally visible at the margins of the major forms where paint applications are thin or where the margins of adjacent forms do not overlap. Paints were applied thinly and in a single layer, closely following the contours of the underdrawing. The white ground is frequently visible through the thin paints except for the most opaque values. The dark values of the building forms were executed wet-into-wet using paints with a cream-to-liquid-like consistency, generally leveled smooth with the canvas texture visible and little brushwork relief. The dark paints frequently exhibit a very fine, crystalline, semi-opaque surface efflorescence associated with insoluble carboxylate salts. It is suspected that all paints contain aluminum di-stearate pigment suspending agents, which were added by manufacturers starting in 1921. With time and elevated or fluctuating temperatures, these stearates evolve into an elevated mobile phase liquid and migrate to areas of lower internal pressure, such as the design surface, resulting in an opaque bloom upon reversion to a solid or waxy phase. Dark paints and those at the edges of forms are applied in long, linear brushwork, executed quickly and wet-into-wet, resulting in frequent raised ridges of paint. Light values are applied using a more time-consuming wet-into-dry technique with matte, stiff, paste-like consistencies and textured ridges of short, scrubbing brushwork and short linear brushwork recorded in the cured paint films. X-ray fluorescence and UV auto-fluorescence suggest that bright white highlights in the sky are zinc white, light sky blues are ultramarine and zinc white mixed with cadmium yellow, and dark crimson passages are composed of alizarin, red ochre, and umber. The other colors are iron earths.

Surface Coating: FTIR analysis suggests that an original butyl methacrylate was sprayed over the work without cleaning off the fine, black soot. There is no extant documentation by conservator Caroline Keck of the conservation treatment of the work. Numerous recent attempts have been made to reduce the development of opaque waxy bloom formations, using both iso-butyl methacrylate and Regalrez 1094, both with Tinuvin UV inhibitor. These can be observed in UV auto-fluorescence images. In 2018, the central sky forms were cleaned of old varnishes and an underlying fine, black soot that had been previously sprayed over. This was achieved using a Shellsol odorless alkane and isopropanol carbopol solvent gel, applied with Japanese tissue strips to prevent abrasions of the high threads.

Framing, Backing, and Hanging Hardware: The work is installed in a Georgia O'Keeffe Museum reproduction, Georgia O'Keeffe/George Of-designed "clam shell" profile, OK III, metal-leaf frame with micro environmental gasketing and Rhapid gel provisions in the secondary backing panel. The entire work is gasket sealed and conditional to a RH of 45%. The work is framed using Optium non-reflective, non-static, acrylic glazing and an insulated poplar backing strainer.

The work has a history of cracking and cleaving paints in areas where zinc and lead white in oil were applied in the central negative space sky regions of the upper half of the work, and the tacking, turn-down edges. Additionally, stretcher bar creases, with intermittent cracking, developed historically. Several cracks observed in the UV examination were previously consolidated with a protein consolidant (possibly isinglass), while others were clearly consolidated using BEVA.

All active cracks were previously consolidated with a 50/50 aqueous solution of Aquazol 50 and 200, using a warm-air pencil, in 2006. They currently appear to be relatively flat and secure. Intermittent cracks, including both stretcher bar lip and canvas weave, have developed at the bottom left and right corners.

Varnish separation was treated in 2006, and the varnish now generally appears uniformly adhered and transparent. There is a previously unrecorded gouge at the lower left that has been retouched. Also noted were two new, small abrasion losses on the street lamp fixture. Because the commercial primer contains only trace amounts of Pb and Zn, soap micro-protrusions are infrequent and have only occasionally resulted in isolated and aggregated pinpoint losses in dark paints, with white primer visible. These have been generally consolidated and inpainted.

In 2018, the central sky forms were cleaned of old varnishes and an underlying fine, black soot that had been previously sprayed over. This was achieved using a Shellsol odorless alkane and isopropanol carbopol solvent gel, applied with Japanese tissue strips to prevent abrasions of the high threads. Previously discolored gouge fills in the middle background, just below the center, and the upper, viewer's left edge, were cleaned, refilled using Flugger calcium carbonate in an acrylic binder, and inpainted using Schmincke watercolor. The artist's original semi-gloss paints were slightly re-saturated using dilute Regalrez® 1094, a hydrogenated oligomer of styrene and alpha-methyl styrene in Shellsol OMS.