At the end of last year the Filipino Traditionalist Catholic blog Dei praesidio fultus published a comprehensive article on the use of blue -- or, rather, cerulean -- vestments for the Feast of the Immaculate Conception:
The article defends the existence of the privilege while meticulously noting the restrictions placed upon it to prevent its indiscriminate dissemination. The privilege was not automatically given to every portion of the former Spanish empire, but had to be specifically petitioned by a Hispanophone diocese, ecclesiastical province or national hierarchy from the Holy See and granted by the Sacred Congregation of Rites.
