Okay, I'm going to try to "think out loud" to address some questions so far.
If you feel anything catching or "lifting" as you move your fingers up the hair strand, you have porous or overly porous hair. How much the cuticles lift will depend on how porous you are (and hearing a "squeak" sometimes isn't good news ... it often means your hair is suffering from lack of moisture).
Finishing products can sometimes be helpful in helping to keep moisture retained within the hair shaft on a temporary basis, but your best bet is to fill in those gaps if possible with a reconstructor. Some sources advocate protein-based semi/demi-permanent or temporary color rinses (such as Sebastian Colourshines, Clairol Jazzings or Goldwell Colorance). Despite the fancy marketing, however, you are simply reconstructing your hair with a slight color boost and shine glaze.
I hate to say this, but you cannot have porous hair unless you have some type of damage, no matter how healthy you think it may look and feel. Porous means damaged to some degree. You may not be OVERLY porous, but in normal, damage-free hair, the cuticles lie down flat like roof tiles. If they are lifted, it means something has disturbed them, be it chemicals, sun, overprocessing, mineral deposits, etc. That is not to confuse the very, very, VERY slight lift of the cuticle layer on curly hair caused by the way our hair spirals and bends with hair that is actually porous. That isn't going to make you suck up gallons of conditioner or give your hair strands a puffy, bloated appearance.
Technically, the float test says if your hair will float on a glass of water for more than two minutes, the cuticle layer is healthy. If the hair sinks, the cuticles are raised and you are porous to some extent. This is fabulous in theory, but ... Because our cuticles naturally are ever-so-slightly raised, we are often going to sink a lot despite our relative porosity. My hair sinks before the two-minute mark and I have some of the lowest porosity known to mankind.
Color can cause porosity depending on how well your hair has taken the processing. I have permanently colored for years, but my porosity remains quite low -- probably because I am a freak about potential chemical overprocessing and how I take care of my hair between colorings. If you are being overprocessed, even with salon color, it can cause damage and, subsequently, higher porosity.
If you use bleach, your hair's porosity immediately increases just by nature of the processing. Bleaching, in effect, blows "potholes" into your cortex and you must be filled with a protein reconstructor to rebuild the damaged hair shaft. If you are not properly reconstructed, your hair will automatically test as overly porous because of all those potholes.
Hair Stylist and Curly Hair Specialist - St. Petersburg, FL (Tampa Bay)
Blog: Live Curly, Live Free
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Sulfate- and non-water soluble silicone-free since 04/22/2002
3B, brunette: medium texture, low porosity, high density