For a traditional-looking certificate, select a blackletter style or similar font for the title of the certificate.
These styles have a distinctly Old English look that conveys formality and weight.
From there, add script and other fonts as needed to complement the look and enhance legibility.

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Blackletter and Uncial Fonts
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Blackletterfonts lend a traditional look.
A script or calligraphic font works well for the title if you want a contemporary-looking certificate.
Be bold and mix a blackletter title with sans-serif pop in for the rest of the text.

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Font Usage Tips
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Size and capitalization matter with these fonts.

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