Yousuf Karsh used large-format cameras, specifically Rolleiflex TLRs, which produced both 8x10" and 4x5" negatives. This allows for much more detail and sharpness than standard 35mm negatives. By looking at his photos, I'd say he used film which had fine grain structure, and considering that Karsh's career began in the 1930s, he would have been using relatively slow films, which would also indicate fine grain structure.
Karsh is most famous for his portraits, of course, and the style can be described as formal. What is unique about Karsh's style is his use of light to model his subjects' faces in an almost sculptural fashion, using a lot of backlighting and sidelighting. His work is high in contrast - the highlights are very bright and the shadows are quite dark.
Karsh generally cropped quite close into the subject, at most showing the upper body and often just the head and shoulders. Generally there is very little background, so as not to distract from the subject, and he used no props or decorations that might attract attention away from the central figure of the portrait. In cases where he did use a background, it is usually simple—frequently black. Most of Karsh's work would not be considered environmental portraits. In the photos that might be considered environmental, it is achieved with minimal and straightforward clues.
Karsh became a master of the "inspection" technique for developing negatives, which was the method of choice of most professionals well into the 1930s, the time frame in which Karsh began his career. The inspection technique, really only suited for 4x5" and larger film, involves developing negatives by hand, traditionally under a green safelight, to produce optimal highlights in specific areas of the image. Development by inspection is not used much anymore in favour of time and temperature development, which is considered more more precise and more repeatable. The inspection technique, however, allows complete and total control over every image. When using this technique, you must judge through the base of the negative rather than the emulsion side. Since the shadow areas are difficult to judge using this technique, you always judge the hightlight, rather than the shadow densities. The gist of the technique is to pull the negative from the developer when the highlights appear as substantial black. To guard against overdevelopment, you have to learn not to allow the high values to get too dark. Karsh used this technique to create negatives that have significant tonality.
3 of Karsh's portraitsTennessee Williams:
I feel that this photo is a great example of Karsh's minimal use of props and background in a photo that could described as environmental. The only clue to the subject's profession is the inclusion of a typewriter, from which you could gather that he is a writer. However, one does not know what kind of writer, thus one's interest is piqued. The lighting around the subject's shoulders gives definition and separates the subject from a background which is similar in tone to the clothing. The subject's gaze follows the line of smoke which hovers above his head, and the viewer's eye is drawn around the circle made by the water glass, typewriter, lamp, and the subject's face.
JFK:
I think the photo of President Kennedy shows Karsh's ability at subtle tonal control. At first glance, the subject appears to be the same tone as the background, but as you take a longer look, you realize that you can see every pore in his face, the structure of his nose, all his veins - you can "feel" the subject of the photo. This photo also demonstrates Karsh's keen sense of societal symbols. Kennedy's face is in profile, turned toward very direct frontlighting, perpendicular to the camera, and he is gazing towards the light with his hands almost in a prayer-like gesture, symbolizing America's time of hope and a President who successfully blended secular and religious sentiments.
Churchill:
This is probably Karash's most famous portrait. It is definitely the most famous portrait of Winston Churchill, and came to be a public symbol of Britain's dogged determination during World War II. I think the background lighting here is amazing - the particular square in the wall that frames the subject's head and shoulders is lit from the interior of the frame, unlike all the other squares in the wall which are dark along the interiors. Again, the backlighting separates the subject's shoulders from the background quite nicely. Karsh only had two minutes to make Churchill's portrait, and he managed to capture the "Churchill scowl". Karsh captured that aspect of Churchill's character by plucking Churchill's cigar from his mouth moments before taking the photo, and the viewer might be left wondering if Churchill is a bulldog, or a petulant baby.
