The Shulhan Aruch (O.H. 272:2) rules that one may use wine directly from the wine press, which has not fully completed its fermentation process, for the purpose of Kiddush. Based on the Gemara (Bava Batra 97a), the Shulhan Aruch goes on to say that one may even squeeze grapes and use the resulting juice for Kiddush. Nevertheless, the Mishna Berura (M.B., O.H. 272:5) says that the way to observe the Mitzvah of Kiddush in the most preferred manner (“Mitzvah Min Hamuvhar”) is to use wine which has fermented for at least forty days. Wine nowadays fulfills this forty-day benchmark.
Rabbi Ben Zion Abba Shaul (Or Lezion, vol. III, ch. 15, § 4), based on the aforementioned Mishna Berura, rules that it is preferable to use wine and not grape juice for Kiddush at night. On the other hand, Rabbi Ovadia Yosef (Hazon Ovadia, vol. VI, pg. 99) says that if one prefers the sweet taste of grape juice over the taste of wine, one may use it for Kiddush.
The Shulhan Aruch (ibid:4) says that, although the Ramban considers white wine invalid for Kiddush, the custom is to do and is therefore permitted. Regarding adding red wine to one’s white wine to render it red, the Ben Ish Hai (Rav Pe’alim, vol. III, Orah Haim, § 11) rules that this would be considered an act of dyeing (“Tzove’a”), and would therefore not be allowed on Shabbat. Although Tzove’a does not apply to foods, the Ben Ish Hai writes that in this case one has the express intention of coloring one’s white wine. Nevertheless, Rabbi Shalom Messas (Shemesh Umagen, vol. II, § 4:7) and Rabbi Ovadia Yosef both rule that one may add red wine to white wine even if it changes the color.
Summary: Besides red wine, one may use white wine or grape juice for Kiddush. One may color one’s white wine with red wine on Shabbat.