The citation below comes from the Official Website of William Perehudoff and describes the work of 1980s. 

Toward the mid to late 80s, Perehudoff pares out the thick gel but retains the more organic or biological shapes of colour that show this immediate brushwork. Now the background comes more into play. The thin stains of diaphanous colour loosely echo the square of the canvas to contain the central colour forms. This is where Perehudoff’s mastery of composition comes into play. The central forms neither simply recede through this window-like opening, nor extend out, but hover, creating a vibration between back and forwards, bringing a soft vitality to the painting- source: 

https://williamperehudoff.ca/section/420798-William-Perehudoff-Paintings-from-the-1980-s.html