How did the Renaissance affect art? What was its significance?
I would actually suggest that one particular area where art was greatly affected through the Renaissance period was in the praising of the artist. The artists of the Renaissance are praised primarily because they were some of the first to be able to assert their own voice in the creative process. We understand Michelangelo’s meticulous attention to detail in his frescos and we grasp the fusion between mathematical and artistic perfection in Da Vinci because they told us about it. Prior to this, social forces or religious subservience subdued the voice and notoriety of the artist. Yet, this was not the case at all in the Renaissance. In this setting, the artist was able to argue that they should be as much a part of the work as much as the created work itself. This view of the artist as an integral focal point and one within whom the stroke of genius lives is something that we owe to the Renaissance for being able to raise the role of artist from one of servant to master. One cannot imagine Raphael being subservient to anything except that, which is his own choosing. To this extent, it is this idea that the artist has autonomy and freedom and can create their own rules that becomes one of the legacies of the Renaissance and greatly impacted how art was viewed then and how it was viewed afterwards.
The Renaissance, whose name translates to "rebirth" in French, revived a reverence for Classical sculpture and subject matter. The philosophy of Humanism, which developed in the 14th-century, at the beginning of the Renaissance, dismissed the concept of humanity that was standard during the Middle Ages—that is, that humanity is inherently sinful. Instead, humanism valued rationalism and the beauty of the human body, which the previous era had deemed the source of sin. Instead, the body became a source of inspiration.
Classical and Hellenistic methods of sculpture and architecture were revived by figures such as Filippo Brunelleschi and Donatello who studied in Rome and returned to Florence to work.
A revival in Classical education, particularly Euclidean geometry, revolutionized painting. Three-point perspective created the illusion of depth in works, such as in Raphael's School of Athens. This technique, in addition to more faithful renditions of the human body due to studies in anatomy, eliminated the flatness that was common in so many Medieval paintings and frescoes.
One of the most powerful effects that the Renaissance had on art was simply the fact that many cities and individuals gained enough wealth and security to encourage and fund the exploration of and production of various types of art. Whether it was a small city-state on the Italian peninsula or a wealthy nobleman in England, the availability of funding made it possible for various artists to flourish and for young people with the opportunity to aspire to be artists instead of struggling some other way to make a living.
Just as today the availability of money for research or the arts will determine the opportunities, the vibrance and various other things of either pursuit. Without the money that changes in trade, etc., brought during the Rennaissance, the explosion and proliferation of wonderful art would not have been possible.