Joyce uses imagery to establish motifs and cultivate thematic unity in A Portrait of the Artist as a Young Man. The most notable imagery in the first chapter is the visual and tactile juxtaposition of wetness and dryness. In Chapter 1, Part 2, young Stephen recalls being pushed into a ditch:
It would be nice to lie on the hearthrug before the fire, leaning his head upon his hands, and think on those sentences. He shivered as if he had cold slimy water next his skin. That was mean of Wells to shoulder him into the square ditch because he would not swop his little snuffbox for Wells’s seasoned hacking chestnut, the conqueror of forty.
Here, wetness symbolizes shame. The phrase "cold slimy water" evokes both physical and psychological discomfort. Visual and tactile imagery enhances the early memories of Stephen Dedalus, and the juxtaposition of opposing sensations helps explain why Stephen associates certain feelings (like shame) with certain sensations (being cold and wet).
Heat and cold provide other instances of opposing imagery. In Chapter 1, Part 2, Stephen recalls his early childhood memories:
Mother was sitting at the fire with Dante waiting for Brigid to bring in the tea. She had her feet on the fender and her jewelly slippers were so hot and they had such a lovely warm smell!
Heat represents intense physical affection (as when Stephen recalls his mother's "lovely warm smell," being cared for by Brother Michael or being embraced by a Dublin sex worker); cold represents propriety and chastity. These sensory contrasts help establish how Stephen experiences the world around him. They also give the reader a sense of Stephen's perceptions of the world and help explain the significance he attaches to each sensory experience.
The word "smell" appears in Portrait over 30 times and ultimately comprises a huge portion of the novel's sensory imagery. Olfactory descriptions in its early chapters help illustrate the visceral experiences of childhood. In Chapter 1, Part 2, a young Stephen Dedalus dwells on the smell in a chapel:
There was a cold night smell in the chapel. But it was a holy smell. It was not like the smell of the old peasants who knelt at the back of the chapel at Sunday mass. That was a smell of air and rain and turf and corduroy.
Olfactory imagery is significant to the story because it recurs so frequently. To that end, Stephen's memories of the past and experience of the present are often described in terms of smell. Here, the chapel's "holy smell" differentiates it from the peasants who attend Sunday mass. This suggests a separation between the church (a pristine, holy entity) and the imperfect, inherently-sinful humans who enter it. In later chapters, as Stephen becomes an adolescent, the difference between the sacred and the profane becomes even more apparent. Rather than describing the chapel in lofty, abstract terms, the young Stephen interprets the world through his senses; this often results in observations about the sights, sounds, and smells of Dublin.