I always keep a handful of both blue and black pens when I meet people to notarize. Some documents have very specific rules around ink color. Blue ink is sometimes required on notarized documents to help distinguish the original document from any photocopies or faxes that may be made later on. The use of blue ink is not as common as black ink, but it is sometimes used as an additional security measure.
In some jurisdictions, the use of blue ink on notarized documents may be required by law or regulation. In California, some types of real estate documents, such as deeds and mortgages, must be signed in blue ink to be considered valid.
Also, the use of blue ink can help to prevent fraud or forgery. Because blue ink is less commonly used than black ink, it may be more difficult for someone to create a fake document that appears to be an original. This is especially important for legal documents that may have a significant impact on the parties involved, such as contracts or deeds.
So, at the end of the day, the use of blue ink on notarized documents can help to provide an additional layer of security and prevent fraud or forgery, even if the use of black ink is more common and generally accepted for most notarized documents. I welcome any other questions on the topic, thank you!