<p>The transmittance of information should not be dried NOR bland, but must be mosaic to attract attention.
The transmittance of information should not be dried OR bland, but must be mosaic to attract attention.</p>
<p>Which one is correct?</p>
<p>The former, I believe.</p>
<p>It is the latter. “[S]hould not be dried or bland” roughly means “should not be dried or not be bland.” The “not” encompasses both adjectives, so “nor” would yield double negative. You can also say “should be neither dried nor bland” or “should not be dried, nor should it be bland.” There are slight differences in meaning between these structures but roughly they are equivalent.</p>