There is a long history of Kodak color papers, and I'm not sure what you mean by recent. As you can see from the Kodak links, there is also a difference between photofinishing papers and custom lab (and amateur lab) papers. If you go way back (the 1940s, or maybe late 30s), the first were photofinishing papers used exclusively by Kodak to print Kodacolor. Kodak also coated a special Kodachrome on fairly thick white plastic film to make Kodachrome prints from slides during this period. Kodak kept its color printing in house until the late 1950s when type C paper for printing color negatives was introduced. Very shortly later, type R paper for prints from color slides was introduced. (Ansco had long offered Printon plastic printing material for prints from slides.) Type C materials were a revolution in photography. Soon there were several imitators (generally inferior and incompatible) from various manufacturers. Kodak published its chemistry, and there were several companies (particularly Unicolor) that made compatible processing solutions. In the 1960s, Type C material was improved and renamed Ektacolor, several improvements in Ektacolor followed. During this period, Kodak also experimented with different surfaces for its color paper. Color paper was traditionally available only in F, glossy, but now Kodak introduced in in E (fine-grained luster), N (luster, smooth), and Y (luster, silk) surfaces as well. There may have been others as well.
A major change happened in the mid 1970s, a little after Kodacolor II was introduced. The paper was improved greatly, especially in stability, and a new process was introduced for the paper. The new process eliminated the benzyl alcohol in the developer and improved the blix. I forget the name of this process, but it evolved over time into RA-4. My memory fails me for the exact chronology here. There was a name change (I forget what it was) to distinguish the new process material. I think it was about 1990 when Kodak introduced a new paper in three contrast grades - Portra, Supra, and Ultra - and the current RA-4 process. Kodak also continued to produce a reversal paper for printing slides up trough this period, with a process different and improved over the original Type R material. Sometime around 2000, Endura, with markedly improved stability, was introduced. The multiple contrasts were eliminated, and the metallic surface was introduced.
This is pretty sketchy. Since it is from memory, it also may have some errors. Hopefully, others will correct those and will expand on the facts a bit. I have not included any of the history of Kodak's photofinishing materials, because I simply don't know it. But these were a separate line with their own characteristics and applications. I have also not included any history of the specialty products, such as the display films and print films.
