Precision of communication between a composer and a sound engineer - noticeable in early Dobrowolski's scores or Kotoński's 'Study?' - is quickly substbstituted by a tendency to experiment with this communication. As early as in 1964 Bogusław Schaeffer started working on a graphic score, full of new symbols which are well-defined by the author but which above all serve as tools of identifying the potential actions of the sound engineer. 6 years later Włodzimierz Kotoński composed a piece which de facto is deprived of graphic symbols. It is a text-score describing the most important principles of composing works which would create a family of electronic pieces called 'Aela'. Even though the text is accompanied by a 19-page graphic score, it solely presents an exemplary production. It is probably not a coincidence that in this period the most significant sound engineers in the Studio - Eugeniusz Rudnik and Bohdan Mazurek - became rightful composers whose works were added to the archives. These few scores made it clear that the fact that composers naturally 'passed' some responsibility for the final shape of the piece onto musicians was a perfect vehicle for experiments. Where would we find a better reflection of John Cage's belief that it is impossible for a composer to foresee the outcome of experimental action? Having in mind the above definition, seemingly the most conservative Studio's activity - writing scores - is the one that most clearly embodies its eexperimental nature. The PRES Scores album is dedicated to the ambivalence of conservatism and experiment. Scores on paper are what the composer leaves behind and this way requires or at least allows subsequent realizations. Experimental scores should at least allow experimental realizations. The album presents some of them.