Question

The cyanotype is a historic photographic printing process that produces a Prussian blue monochrome image. The procedure begins with the preparation of the sensitizing solution, created by mixing equal parts of ammonium iron(III) citrate and potassium ferricyanide. This mixture must be blended in a dim environment to prevent premature light activation. Once prepared, the sensitizer is evenly coated onto a heavy paper substrate using a brush or sponge, and the paper is left to dry completely in the dark.

After the sensitized paper has dried, the artist places a negative or flat object directly onto the coated surface. A sheet of clean glass is clamped over the arrangement to ensure firm contact and prevent shifting. The assembly is then exposed to ultraviolet light, typically from direct sunlight or a specialized UV lamp, initiating a chemical reduction of iron.

Immediately following exposure, the paper must be washed thoroughly in running cold water for at least five minutes. This wash removes the unexposed, water-soluble iron salts, leaving behind the insoluble Prussian blue dye bound to the paper fibers. If this washing step is omitted or cut short, the remaining unexposed chemicals will slowly react to light over time, causing the image to darken and eventually fade entirely. Finally, the wet print is hung to dry, a stage that can be accelerated by adding a drop of hydrogen peroxide to the final rinse water to rapidly oxidize the blue pigment to its deepest shade.

Based on the passage, what is the direct consequence of omitting the water wash step immediately after exposing the cyanotype assembly to ultraviolet light?