ho inteso nel senso negativo di "entrare in contrasto"...ciao

the literal translation here is they mutually enlarge/augment/- each other
pick one lots of options follow

the phrase means:

their own individual effect is amplified(made larger, bigger, intensifiedmore bearing) when combined with the effect of the other element in the picture.

Dictionary.com Unabridged (v 1.1) - Cite This Source
aug·ment /v. ɔgˈmɛnt; n. ˈɔgmɛnt/ Pronunciation Key - Show Spelled Pronunciation[v. awg-ment; n. awg-ment] Pronunciation Key - Show IPA Pronunciation
–verb (used with object) 1. to make larger; enlarge in size, number, strength, or extent; increase: His salary is augmented by a small inheritance.
2. Music. a. to raise (the upper note of an interval or chord) by a half step.
b. to double the note values of (a theme): In the fugue's development the subject is augmented.

3. Grammar. to add an augment to.
4. Heraldry. to grant an augmentation to (a coat of arms).
–verb (used without object) 5. to become larger.
–noun 6. Grammar. a prefixed vowel or a lengthening of the initial vowel that characterizes certain forms in the nonpresent inflection of verbs in Greek, Sanskrit, Armenian, and Phrygian.


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[Origin: 1375–1425; late ME au(g)menten < AF, MF au(g)menter < LL augmentāre to increase, deriv. of augmentum an increase (aug(ére) to increase (akin to eke) + -mentum -ment) + -ā- thematic vowel + -re inf. ending]

am·pli·fy /ˈæmpləˌfaɪ/ Pronunciation Key - Show Spelled Pronunciation[am-pluh-fahy] Pronunciation Key - Show IPA Pronunciation verb, -fied, -fy·ing.
–verb (used with object) 1. to make larger, greater, or stronger; enlarge; extend.
2. to expand in stating or describing, as by details or illustrations; clarify by expanding.
3. Electricity. to increase the amplitude of; cause amplification in.
4. Archaic. to exaggerate.
–verb (used without object) 5. to discourse at length; expatiate or expand one's remarks, speech, etc. (usually fol. by on): The preacher amplified on the theme of brotherly love.


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[Origin: 1375–1425; late ME amplifyen < MF amplifier < L amplificāre to increase, augment. See ample, -ify]

—Related forms
am·pli·fi·a·ble, adjective


—Synonyms 1. increase, intensify, heighten. 2. widen, broaden, develop.
—Antonyms 1. contract, reduce. 2. condense, abridge.
Dictionary.com Unabridged (v 1.1)

Or "have a mutual magnifying effect" or "end up being magnified by their combination".

Idea, bit in brackets is optional.