Red has connotations of blood and anger. Here Hughes uses red in many events in Plath's life; symbolising whenever she has been filled with raw emotion and anger. This is as a result of both her desire to succeed in the poetry world, and the lack of control she has in her life.
Red was not the only colour Hughes chose to use to describe Plath. White was used to show the purity within Plath:
"If not red, then white. But red
Was what you wrapped around you."
The language Hughes uses here states that underneath all of Plath's rage and raw emotions, she is pure and innocent, just as Hughes first saw her in 'Fulbright Scholars'. However, Plath chooses to engulf herself too much in her dangerous emotions according to Hughes, as it was her ambition to succeed as a poet, even by throwing away all other aspects of her own life. Plath feels a sense of comfort in 'wrapping' herself inside the emotions, as if they are used as a barrier to protect her from the harmful dangers of the outside world.
Hughes talks about the room that he and Plath shared, using it as a metaphor for their life:
"Our room was red. A judgement chamber.
Shut casket for gems. The carpet of blood"
Here Hughes is able to show how he felt a sense of entrapment in his relationship. This is shown through the word 'chamber' in 'a judgement chamber', and 'shut casket for gems'. The idea of the carpet and room being red shows that Plath's rage and anger adds to the idea that Hughes is bound in the relationship by Plath's extreme emotions, and the thought that this powerful being takes over their everyday domestic lives. Hughes' poem 'Totem' mentions that Plath painted her room with red hearts to ward off the evil spirits that were taking over her life. This links to their room being a 'judgement chamber' with the red surrounding them.
Midway through the poem, Hughes states that only Plath's work was able to survive through time:
"Only the bookshelves escaped into whiteness."
Here the idea of the 'bookshelves escaping into whiteness' shows Plath was never able to return to the innocent attitude she once possessed, and was engulfed and overwhelmed by the raw emotions which fuelled her to her death, but more importantly shows that the only major pure good in Plath's life was the sacred poems she wrote.
Although Plath has been described as red; being overwhelmed by anger and raw extreme emotions, she still attempts to present herself and her life differently:
"Everything you painted you painted white"
Hughes illustrates that Plath attempted to hide all of the pain and despair in her life by putting on a sense of innocence and misguidance. The imagery of plain whiteness in the sentence contrasts greatly to not only the effect Plath had on Hughes and the people surrounding her, but her life in general. This is often known as a 'white-wash', when the unsavoury truth is either not mentioned, or it has been disguised.
Later on in 'Red', Hughes opens up a new side of Plath a side we learn about later in the book, and for this he uses the colour blue to describe her calmness:
"Blue was better for you. Blue was wings."
Here the colour blue shows calm and freedom, which Hughes says is better able to represent freedom is shown through the word 'wings', creating the idea that she is able to escape and fly away from all the troubles in her life. In the poem 'Re
Hughes shows when this blue emotion is introduced into Plath's life, when she gives birth to their first child:
"Kingfisher blue silks from San Francisco
Folded your pregnancy
In crucible caresses."
The 'Kingfisher blue silks from San Francisco' are the blankets they wrapped their son in once he had been born. The use of blue adds the sense of calmness to the scenery, as well as it being able to reflect Plath's emotions and feelings freedom and contentment. The blue is related to a 'crucible'; it contains the high temperature reactions and rage that are found within Plath.
He goes on to describe that blue was most probably Plath's greatest emotion that she had:
"Blue was your kindly spirit -- not a ghoul
But electrified, a guardian, thoughtful."
Here we are able to see that underneath all of Plath's red anger and rage she has these feelings of calmness and freedom. The use of the words 'kindly spirit' and 'a guardian, thoughtful' adds to the sense of calmness and caring. As well as showing these ideas through the colour blue, the main quality is that Plath seems to finally be in control of her life. The one time we see this stage of 'blue' in Plath's life is in 'Remission', where the bringing of new life brings new happiness and gets rid of her rage.
At the end of the poem, Hughes concludes Plath's timeline of events by using the colours to show the misery she was eventually left with:
"In the pit of red
You hid from the bone-clinic whiteness.
But the jewel you lost was blue."
The idea of a 'pit of red' further adds to the idea that Plath has been engulfed by raw and extreme emotions, and she is not able to escape. However, she is using this red to cover up the innocence which was preventing her from succeeding in the poetry business. The calmness she had at the time of her pregnancy had been destroyed by the anger in her life, which then took over her and caused her to eventually end her life.
By using different colours to portray Plath's emotions at crucial stages in Plath and Hughes lives, Hughes is able to sum up Plath's life and the whole collection of 'Birthday Letters'. He shows how she had gone from an innocent Fulbright scholar, to a woman with raw emotion and anger. He does this by pushing her into the poetry business, which eventually destroys her life and all other feelings and attitudes she kept. For this reason, 'Red' is the most representative text in the whole poetry collection.