Therese Belivet is bothered. What troubles her is this:
“… the sense that everyone was incommunicado with everyone else and living on an entirely wrong plane, so that the meaning, the message, the love, or whatever it was that each life contained, never could find its expression.”  Therese senses that the stuff of humanity has been thinly sliced and peeled apart so that each one of us lives alone, able to share inanities but unable to escape our individual plane and make a meaningful connection. Her confession to the reader on the opening pages of The Price of Salt becomes a motif in the film adaptation.
Carol repeatedly frames its two main characters using isolated physical and focal planes. Therese is obscured behind and reflected by windows. Carol is pictured in shallow focus amid crowds of shoppers, she is sandwiched between layers of plate glass shopfront, and she is captured by Therese in photographs. Both women appear as reflections in mirrors throughout the film. The very surface of the film image evinces an interest in separation and isolation; the choice of Super 16mm as an acquisition format  results in a distinct grain structure, so that the frame presents itself as a delicate arrangement of matter that could be flung apart again at any moment. The camera shows us the two women trapped inside boxes: Carol framed by a window as she stands alone at a party, and Therese seen from the inside of her workplace locker as she shuts her eyes and wishes to be elsewhere.
Behind the counter at Frankenberg’s department store, Therese looks as though she may be trying to become invisible by sheer force of will. When she goes to visit Carol at home and Carol’s estranged husband arrives unexpectedly, she discovers that no matter how excruciating the situation, she remains present to cause consternation and marital strife. Therese is sent away, put on a train back to the city. She has become one of the figurines in the department store train set she admired – consigned to her role, unable to connect. She cries, turning her face to the darkness outside the carriage window so that we view her as a reflection trapped there in glass. Whenever her boyfriend, Richard, asks her to go away with him, she seems to hope in her reticence that she can slip free of the world.
Her aspiration to become a photographer is a further preoccupation with manipulating reality; each frame on the film roll is a slice of another life presented to the viewer in a compact and accessible form. Whenever Therese takes a photo she is sampling alternate planes of reality with her camera’s eye, searching for a plane she would prefer to inhabit. She is unhappy with her samples, until she summons the courage to take a photograph of Carol and so finds her muse. Therese and Carol begin increasingly to populate the film frame together instead of being separated onto their individual planes of reality by the usual shot/reverse editing structure. They make love for the first time immediately after we see them at last occupy the same reflection in the mirror of their motel room, as if the one thing happening made the other possible.
It is an audio recording that betrays them. Carol vanishes herself from Therese’s field of view when a hostile society threatens to punish her for the crime of offending its mores. Therese tries to remake their broken connection by telephone but it just won’t do. Words cannot bridge the gap between them because words are too often used to keep them both trapped in miserable isolation:
“Are you Frankenberg material?” and
“morality clause.” Therese protests that she is not talking about
‘people like that’ when she tries to broach the subject of a same-sex love affair in conversation with Richard. What she is talking about, though she cannot yet admit it, is a confusing but wonderful transformation that is happening to her, Therese Belivet, not some imaginary and easily marginalised Other. The film shares her conviction. Quite apart from its sexual politics, Carol is about the small miracle of two lonely people discovering how to express their message, their love.