The similarities/differences between Italian and Northern Renaissance art are the following:
Influenced by: both are influenced by the idea and power of education, individualism, and cultivated knowledge of the Classics, scriptures, and writings from early Christianity.
Typical subject matter: they both exhibit the idea that it is the responsibility of a man to participate in his community and move towards building his relationship with God
style: Northern Renaissance is based on empirical observation and attention to details of visual reality. While the Italian Renaissance, is based on visual reality through proportion, perspective, and human anatomy.
Known for : they both portray the nature through emotional characteristics and religious scenes.
Medium: Italian Renaissance uses focus on the upper-middle class to share their thoughts and belief, While the Northern Renaissance focused more on the majority of the population, or the lower class.
Example Italian renaissance showed often classical mythology, while Northern renaissance showed usually domestic interiors and portraits.