When one speaks of the characteristics of a quale (our conscious subjective experience), for example when one speaks of things imagined and something perceived, when one says that one is clear and the other diffuse, the best way to interpret this is that the segment of that unitary thing that refers to the qualia (see the concept of the unitary regarding the consciousness in my work “Propositions” -see in publications menu), and the segment that refers to the red color, as an example, presents variations in its structural form, it is the same segment, but with variations, with changes, which manifest themselves at different times, so we say that a red colour we observe is more intense than an imagined one, as it would be with a sound, which maintains the same frequency but change the amplitude (intensity). What varies is this structural form (the same structural form practically, with some small variation), but the segment would be the same, each variation refers to a particular quale manifestation, so we consider that there is something like intensity. The “more or less” intense would refer to the particular variation of the structural form. Just because they are variations you need to consider several qualia to take into account the variation itself, the quale is the minimum unit (that is what we base ourselves on to talk about something), we can not say anything about it, considering it in isolation, without associations with other qualia. In this particular sense, to speak of what a quale expresses, for example, would be absurd, quale by itself does not express something as a metter of speaking.
We must bear in mind that language allows us to talk about the qualia of a structure or form that acquires a particular qualia integration, what qualia constitute a particular structure, a particular integration, but it does not allow us to talk about characteristics of a quale considering the individual entity, it is a limit, I can speak of the intensity taking into account several qualia. To say that a quale is more or less intense than another would refer to the particular variations of the structural form of the segment of the unitary entity that refers to red, variations that we can order in a sequence. I can say that some red is more intense than another, but I can not say anything else about it, I can not say what that particular red is, different in intensity from the other red.
In this way, we must be cautious when we talk about characteristics of a quale. I can associate qualia, but I can not say anything about what red is, considering a single manifestation of red, for example. In isolation, considering a single quale, I can not say that this is intense, for example. I can say what a square is, in the sense of indicating what its elements are, because it forms a particular structure, an integration of qualia (several qualia), and I can associate that with other qualia. Now, if I consider a line of the square as a minimum unit, a particular quale, I can say nothing of this considering it in isolation. If I imagine a line, I can say that it is less intense, considering another quale, that of a perceived line. Sometimes when we say that we speak of the characteristics of the quale, we refer to qualia manifestations, that is, we say that generally a particular quale does not cease to be the case and another quale manifests, the blue of an object does not stop being such and a green manifests itself, for example.
And one more issue to highlight about quale: memory may not be necessary for quale to manifest, rather it is because there is a certain memory that we know that there is quale.