Below is something to consider
I did a quick google search for what you were speaking of, which might have been for mathematical principles of order, harmony and reason underlying the hand painted art designs of the Visconti that has International Gothic and Renaissance influences.
That would be about 1450, where the overlap and transition of influences were still being traced.
What a fascinating subject! Hope the background below might be helpful as you begin your work:
From 1450-1490 there might be beginnings of orderly precision and harmony showing up in art and architecture...but it seems like Michaelengelo's beautiful geometic proportions came after 1500. Leonardo Di Vinci was gorgeously ahead of his time, ahead of his generation. If you can find out more of Leon Alberti, you will also see mathematical harmonies and architecture during 1450 to 1490...but I am not certain how closely you can find such principles linked to printed or handpainted Visconti tarot cards of the period.
Raphael as an artist is considered as one most beautiful examples of such harmony and proportion, who took after Leonardo's style...but his lifetime was 1483-1502, later than perhaps than you are looking for in card design?
http://www.swil.ocdsb.edu.on.ca/ModWest/HUMANISM/art/Raphael.html
Roughly, when I attend art history surveys of the Medieval and Renaissance times, they focus first on the cathedrals and churches in architecture of the country to find influences of architects and mathematicians in illustrating the principles that you speak of. Roughly, it is more evident in Italian art from 1500 to 1530. This is after Raphael.
For Leon Alberti:
http://easyweb.easynet.co.uk/giorgio.vasari/albert/alberti.htm
For international Gothic as an architectural form:
http://ragz-international.com/gothic_art.htm
Italian Gothic (c. 1200-1400)
In its development of a Gothic style, Italy stood curiously apart from the rest of Europe . For one thing, the more obvious developments of the Italian Gothic style occurred comparatively late--in the 13th century. For another, whereas in most European countries artists imitated with reasonable faithfulness architectural styles that were derived ultimately from northern France , they seldom did so in Italy . This was in part because of geographic and geologic factors. In the figurative arts the combined influences of Byzantine Constantinople and classical antiquity continued to play a far more important role in Italy than in countries north of the Alps . Furthermore, Italian architectural style was decisively affected by the fact that brick--not stone--was the most common building material and marble the most common decorative material.
The distinctiveness of Italian art emerges as soon as one studies the architecture. Twelfth-century buildings such as Laon, Chartres , or Saint-Denis , which appear to have been so important in the north, had virtually no imitators in Italy . Indeed, buildings with Romanesque characteristics, such as Orvieto cathedral (begun 1290), were still being built at the end of the 13th century. The Italians, however, were not unaware of what, by French standards, a great church ought to look like. There is a sprinkling of churches belonging to the first third of the century that have northern characteristics, such as attached (partially recessed in the wall) shafts or columns, crocket capitals, pointed arches, and ribbed vaults. Some of these were Cistercian (Fossanova, consecrated 1208), others were secular (Sant'Andrea, Vercelli ; founded 1219). The chief common feature of the larger Italian 13th-century churches, such as Orvieto cathedral and Santa Croce in Florence (begun 1294), was the size of their arcades, which gives the interiors a spacious feeling. Yet in detail the churches vary from the French pattern in a highly individual way.To the extent that Rayonnant architecture is particularly concerned with the manipulation of two-dimensional patterns, the Italian masons produced their own version of the style. In these terms, the facade of Orvieto cathedral (begun 1310), for example, is Rayonnant; the front of Siena cathedral was planned as a Rayonnant facade (), and the Campanile, or freestanding bell tower, of Florence cathedral (founded 1334) is Rayonnant to the extent that its entire effect depends on marble patterning (which is traditionally ascribed to the painter Giotto). Finally, it is perhaps legitimate to see Filippo Brunelleschi's 15th-century architecture as a continuation of this tendency--a kind of Florentine equivalent, perhaps, to English Perpendicular. But before the 15th century, Italian architectural development never appears to have the logic or purpose of northern architecture.
Though the rebuilt Milan cathedral is, in plan and general character, Italianate, its decorative character is mainly derived from the north, probably Germany . The exterior is covered with tracery, which makes Milan cathedral more like a Rayonnant building than any other large church in Italy .
Architecturally, as well, the initial changes involved decorative material. For this reason, the early stages of Renaissance art outside Italy are hard to disentangle from late Gothic. Monuments like the huge Franche-Comté chantry chapel at Brou (1513-32) may have intermittent Italian motifs, but the general effect intended was not very different from that of Henry VII's Chapel at Westminster . The Shrine of St. Sebaldus at Nürnberg (1508-19) has the general shape of a Gothic tomb with canopy, although much of the detail is Italianate. In fact, throughout Europe the "Italian Renaissance" meant, for artists between about 1500 and 1530, the enjolivement, or embellishment, of an already rich decorative repertoire with shapes, motifs, and figures adapted from another canon of taste. The history of the northern artistic Renaissance is in part the story of the process by which artists gradually realized that classicism represented another canon of taste and treated it accordingly.
But it is possible to suggest a more profound character to the change. Late Gothic has a peculiar aura of finality about it. From about 1470 to 1520, one gets the impression that the combination of decorative richness and realistic detail was being worked virtually to death. Classical antiquity at least provided an alternative form of art. It is arguable that change would have come in the north anyway and that adoption of Renaissance forms was a matter of coincidence and convenience. They were there at hand, for experiment.
The use of Renaissance forms was certainly encouraged, however, by the general admiration for classical antiquity. They had a claim to "rightness" that led ultimately to the abandonment of all Gothic forms as being barbarous. This development belongs to the history of the Italian Renaissance, but the phenomenon emphasizes one aspect of medieval art. Through all the changes of Romanesque and Gothic, no body of critical literature appeared in which people tried to evaluate the art and distinguish old from new, good from bad. The development of such a literature was part of the Renaissance and, as such, was intimately related to the defense of classical art. This meant that Gothic art was left in an intellectually defenseless state. All the praise went to ancient art, most of the blame to the art of the more recent past. Insofar as Gothic art had no critical literature by which a part of it, at least, could be justified, it was, to that extent, inarticulate.
