Space made dull and dark by the obscuring effect of ignorance is deficient emptiness.
In other words, deficient emptiness is nothing but space experienced through the filter of ignorance (which is composed of images from the past taken to define oneself, accompanied by wrong beliefs and emotions associated with the images). This explains why when the deficient emptiness is experienced it transforms into space as soon as the wrong beliefs and their accompanying emotions are seen and understood.
Of course, the ignorance has in it, connected to it, the memories of the original childhood experiences that led to the various self-images. Psychodynamic understanding removes the dullness and darkness of ignorance by shedding light on its specific content. This brings about the clarity of understanding, which dissipates the ignorance and reveals the true nature of the deficient emptiness which is immaculate space. – The Void: Inner Spaciousness and Ego Structure, Ch. 19