The prejudice against L2 translation has become an old habit and old habits die hard. In this article the axiom that translators should translate only into their native language, that is the language of their habitual use, is being challenged on the grounds that it is outdated, impossible to attain and most importantly lacking in empirical evidence. Since the processing demands of L1 and L2 translation have rarely been compared, the EDiT project has been designed to investigate how professional translators proceed when they translate into their L1 (Polish) and L2 (English). The article describes the research design and reports on a sample analysis of data collected by key-logging and eye-tracking which provide quantitative measures of cognitive effort when translating in both directions. The translated texts are then corrected by experienced proof-readers to show that both L1 and L2 translations are not flawless and need to be improved.