When I zoom in pdf file which is exported from Photoshop CC, some texts are not clear on pdf file. How do I solve this?

Question

When I zoom in on my architectural portfolio, the clarity of the text becomes distorted and nothing is read. This is especially true for small print. How can I solve it?

Below image is zoomed 375% on the pdf I saved. The texts are almost unreadable.

Answer 1

Some viewers may have problems with clarity when zooming however if the pixels were exported as sharp crisp PNG based PDF the worst issue would be down to the anti-alias of edges not an overall fuzzyness as might be seen with a jpeg image where blocks of 64 pixels are averaged.

Unfortunately fonts exported as small blocks of pixels will clump unless the resolution is increased such that the smallest single letter is about 7-14 pixels high or more.

So in this red lettering the lowercase is 7 pixels high and full height letters are 10 units high.

Check your height of the smallest letters, lets for arguments sake say the recommended minimum is 2 mm high for readability, thus the rule of thumb would be 254 dots per inch. So 300 dpi would be suited but if the text was scaled down to 1 mm high on the output it would need to be 600 dpi to be just as clear.