In Tennessee Williams' 1947 play, A Streetcar Named Desire, filmed in 1951 by Elia Kazan, he uses symbolism to the extreme, from names to the use of lights. This element of lights is one of the most important ones in seeking Blanche's (Vivien Leigh) character. The way she never wants to be in the full light leaves one feeling that she has something to hide. Of course, that is made obvious from the time she arrives at Elysian Fields, but there is something else that she is hiding. She is not only hiding her past but she is hiding the fact that she is desperately hanging on to life, and this may be her last chance. No one but Mitch (Karl Malden) realizes this, too late alas; and she loses him, along with her life (metaphorically speaking.
The first time this light symbol is used occurs when Blanche first meets Mitch at the poker game. She asks him to put the new lampshade that she has bought over the light bulb. She says, "I can't stand a naked light bulb, any more than I can a rude remark or a vulgar action." This statement says so much more than the reader realizes at first. In retrospect, it makes perfect sense. A naked light bulb puts off a lot of light, which makes every imperfection perfectly visible; it makes everything seem vulgar and crude. With the lampshade, everything is much softer, and imperfections are almost invisible. Looking back, I can see that this is Williams' way of telling us that Blanche does not want her inner imperfections or hurting to be seen. She wants to soften them and hide them behind the lampshade of the façade she puts up in front of others, even her sister (Kim Hunter).
Finally, this symbol is brought to the forefront of the story when Mitch tells her that he has never had a good look at her and then proceeds to tear off the lampshade. He then puts her into the light, and he finally sees her for what she truly is, or what he believes her to be. He sees a woman with a dirty past that has lied to him about it. Yet, I would argue that she is not all that bad. She says that she told him things that were not true but they should have been true. She wants to be happy again; and, in doing this, she did some things that she should not have and then concealed them. However, she has concealed them with good intentions, and she deserved another chance.
Blanche has always been afraid that people would see her for who she really is, and that as scared her so she has hid in the darkness. When everything is finally exposed, she is ruined. Maybe she should have told the truth to begin with, but maybe she was too afraid that things would turn out the way they did, so she decided not to ruin her last chance, which, alas, she ended up doing anyway.