Equal font-size numbers do not guarantee equal visual size for Chinese and Latin text. Different typefaces allocate space differently around their visible shapes. Fix the relationship with a controlled optical proof, rather than repeatedly resizing the entire poster. Adobe documents paragraph formatting in Photoshop help and language-related font features in its OpenType documentation. Neither source supplies one universal ratio for all bilingual designs.
Define what must line up
Identify the reader's task. A bilingual title may need similar prominence, while a small English explanation may intentionally be subordinate. Decide whether you are aligning a baseline, the visible tops of letters, or the center of two separate text blocks. These are different goals, and switching between them produces inconsistent adjustments.
Select the actual text and record its font family, size, weight and line spacing. Confirm that a missing character has not triggered a fallback font. Preserve the approved wording while testing. Use the real English name or sentence, because a proof made only of capital letters may not predict how lowercase letters look.
Compare one variable at a time
Place the Chinese and English on a plain temporary background. Keep the Chinese size fixed and vary the English size modestly. Judge the visible letter bodies at ordinary viewing size. Then inspect baseline position or block alignment according to the goal you chose. If the editor offers baseline adjustment, use it locally rather than moving unrelated elements.
As a hypothetical example, a wedding poster might place a Chinese title above a Latin-script couple name. Both could initially use the same numeric point size, yet the English appears much smaller. Increasing only the English slightly and adjusting its distance from the title can improve the relationship. The example is not a fixed percentage recommendation.
Check punctuation and descenders after alignment. A letter such as “g” extends below the baseline; forcing its lowest point to match the bottom of a Chinese character can shift the rest of the name unnecessarily. Conversely, centering separate text blocks may be more appropriate than forcing them onto one baseline.
Test the delivered reading size
Return the proof to the actual photograph or poster background. Export and inspect it at the intended phone or print size. Ask a reader to identify the primary information and read both languages. Good geometry does not compensate for weak contrast or a tiny translation.
Keep the chosen settings in the editable master. If a new background comes from Imagild skills, finish bilingual copy separately as real text. Acceptance means clear hierarchy, approved wording and a stable export; matching two numbers in the font menu is only a starting condition.