A polymer alloy film on a photographic plate (ILFORD, Q-plate) was exposed to the dispersed soft X-rays in the wavelength region between 8.1 nm and 33.6 nm. A direct image recorded on the Q-plate was magnified by means of an optical microscope. The microscopic images for one of the component polymers in the polymer alloy containing silicon had circular spots of about 50 µ m in diameter scattered in a matrix with certain wavelengths of soft X-rays. A change in image contrast of the microstructure was observed in the wavelength range between 8.6 nm and 13.2 nm. This reversal of contrast suggests that these circular spots, or islands, are silicon-rich phases because the L-absorption edge of silicon is 12.3 nm. Spectral soft X-ray contact microscopy is useful in determining the wavelength region suitable for clear microstructure imaging, as well as in identifying constituent elements.