What is the signature Leon Shamroy style? In short, it's an aesthetic in which paradoxically realism and romanticism (at least as these tendencies were understood at the time) are not at odds. This is especially true of his work at Fox, but even in independent productions. A few tendencies stick out:
Undiffused, overexposed light. To generalize, the prevailing practice in the 1930s was to heavily diffuse light, to glamorize the star and to deal with the background, whereas the prevailing practice by the late 1940s was to use harsh light to increase contrast and render rich ink-black tones.
Shamroy seems to be doing both. Light in his image has a harsh intensity yet also a fuzzy glow. The best I can tell, he does not diffuse the light (at least not entirely) but instead overexposes the image to create a similar effect. (You Only Live Once/Lillian Russell)
This goes along with his tendency to underexpose part of the set/frame so that modest illumination will glow.
Spotlights. The star close shots tend to rely on heavy spotlights on the face. At times these will cover the full face, at other times only part of the face (Lillian Russell):
Or a character may enter in and out of one (The Black Swan):
The usage becomes particularly experimental in Daisy Kenyon, both obscuring parts of the face, washing it out into gray, or being distinctly unmotivated:
Overlighting. Shamroy has a strong preference for lighting his figures from above, even without the traditional genre/effects-lighting cues for such treatment (Lillian Russell):
The Diagonal Shadow. Shamroy can hardly be the only D.P. to cast diagonal shadows in the background to differentiate foreground-background relations and to lend a sense of three dimensionality. But the diagonal shadow is a default aesthetic choice for Shamroy and takes on an expressive quality of its own. Here's a shot from Only Live Once, or compare the still of Alice Faye in Night in Rio from my previous post.
The Intense Kicker.
He is not alone in this (WB and MGM both indulged in this practice, particularly for its female stars). What I find interesting is the omnipresence of the kicker in Shamroy's work, often "feminizing" the male stars and appearing at unexpected times.
Grayscale experimentation. 30s cinematography tended to prefer bright brights and dark darks. Shamroy often toyed with the middle, in this shot in Only Live Once...
... or in Daisy Kenyon:
Busy shadow. Shadows fall everywhere, in diagonals, in criss-cross, and in gobo-ed patterns. Whether in black and white (Daisy Kenyon):
or in color (Leave Her to Heaven):
The individuated multiple setup. I had alluded to this in the previous post. Shamroy often choreographed complex crowd scenes with many lights for individual persons rather than relying on a general illumination for the crowd. (Only Live Once):
Here's a complex shot from Lillian Russell:
These practices are so expressionistic that they would seem to militate against any notion of realist photographic practice. And it's true that Shamroy is not going to be lumped in with Arthur C. Miller or James Wong Howe. Yet he made the transition from Paramount to Fox in the late 1930s and his romanticist, experimental tendencies were able to find a new home in the decidedly downcast and realist-oriented studio. I think it is because the way his lighting choices play against genre expectation. Lillian Russell has particularly hard-edged cinematography for a musical biopic. Daisy Kenyon treats its stars in a decidedly unglamorous approach. Leave Her to Heaven is almost bichromatic and non-spectacular. These choices matched Fox's image (and self-image) as distinct, a non-glitzy, "adult" Hollywood studio amid the genre factory. House style, that is, may be a question of structural categories rather than formal similarity.