Do you play any "Storyteller" system games?
I ask because White Wolf's Storyteller system is very good at explaining the different kinds of things that can be learned.
The first type of ability is a talent. This is something that can be nurtured, but can't really be taught. It includes things like brawling, lying to people, and being able to notice details others might miss. This sort of thing is the best thing for direct learning. The behaviors here are easy. You can visualize yourself beating someone up, telling them falsehoods, or seeing that proverbial needle in the hay stack.
The next column of abilities is skills. These are things that one might have an inate aptitute for, but usually they are studied. However, they can be "faked." This would include crafts like soapmaking or leatherworking, how to program a VCR, or shooting a gun. Even if you don't have any training on how to do these, you can attempt it with a +1 difficulty modifier, according to the Storyteller rules. Again, the visualization is rather simple. Just imagine using the skill and there you have it. These are a bit harder to Direct Learn than the talents, but through practice you will activate the skills.
The last column of abilities on a Storyteller chracter sheet is knowledges. These are areas of knowledge such as languages, sciences, medicine, computers, the occult, etc. Under the rules the game, one cannot even attempt an action involving a knowledge unless one possesses a "dot" in the knowledge. These things are very hard to direct learn, simply because they deal so much more with FACTS than with BEHAVIORS. Spontanious activation can and does happen with knowledges, even ones as esoteric as quantum physics, but to have a real "framework," manual activation is still the best route.
Your better off aquiring "research" or "study habits" as a skill then trying for "chemestry" as a knowledge. In truth, chemestry is probably one of the better things for PhotoReading, as the Periodic Table of the Elements, if you truly understand it, is the only "cheat sheet" you'll need.
One thing that I've done is use Direct Learning on biography, in order to Direct Learn <I>modes of perception</I>. So far, I've only absorbed DaVinci and Franklin. Buckminster Fuller is next on the list. The one trivial thing that I've spontaniously activated in the realm of fact is that Franklin was not a Cassanova, although he played upon that reputation in order to live up to people's expectations. Another factoid, about DaVinci, is that his "John the Baptist" is actually Pan. In general we look for people who are "before their time." By we, I mean that I have an "analog" of Franklin and Davinci that I can "converse" with as imaginary friends, and I confer with them before adding other people.
Long story short - consider adding a Master Chemist to your own "board of directors." I've modified techniques outlined in "Natural Brilliance," "The Einstien Factor" and "Think and Grow Rich" in order to stumble upon this method.