Toni,
I posted
a similar question a month or two back and had a couple of responses, but nothing very conclusive. I've done a ton more searching and reading since then and I must admit I haven't come any closer to a real conclusion. In fact, I've actually come to the conclusion that with Kokanee, who we typically agree are biting out of agression rather than feeding, it's all pretty much a guessing game when it comes to which blades work best.
Some brief thoughts on your specific questions:
1) I have no idea which blade makes the most "noise". Noise being, in this case, vibrations which are detected along the lateral line. Is vibration level even the most important factor? Should we instead be paying attention to frequency (hz) or some other unknown characteristic? Presumably the "sounds" put out by a Colorado blade are different from a Dakota blade, or even a "deep cup" Colorado blade, but is one objectively better in all situations? I honestly doubt it. If there is an advantage it's hard to say if it's present in all lakes during any season, etc. The only real good data I've heard is that Colorado blades spin slower than Indiana blades which spin slower than Willow Leaf blades. Since Kokanee trolling is typically done at relatively slow speeds, I am personally going to avoid the Willow Leaf blades.
2) This is one area I feel I can somewhat wrap my head around. I believe a smooth unpainted blade will reflect a lot of light in one angle at a time. A hammered blade will reflect smaller bits of the light in different directions. It's design, I believe the hammered blades probably end up reflecting less light as a hole than the smooth blades. I also believe, although I have no means to test this, that there is probably some effect on the rotation speed due to the extra friction from the additional surface area on the hammered blade. There would also be some effect on the "sound" given off by the blade. Which is best? I think we have all probably caught Kokanee with both types of blades so I'm not sure there's a good answer. I have kinda settled on hammered for unpainted blades under the thought that light in more directions is probably better than more light, but this is essentially something I tell myself to help me make a decision.
3) While polished metal blades are going to reflect light like a mirror in one or several directions, painted blades are going to tend to be a lot more even in it's dispersal of light, depending on the finish. Think of shining a light on a bathroom mirror (smooth metal blade), a disco ball (hammered blade), and a normal wall. The bathroom mirror will bounce the light off at an angle of incidence (I had to look this up to find the precise term) giving you one large spot where the light is focused. The Disco ball will give you lots of smaller spot where the light is focused. A painted wall (assuming it's a relatively flat paint) will give you a much more even distribution of light. A glossier paint will give you a relatively even distribution of light, but there will also be a small amount of the mirror effect as well.
While I can ramble on about it all day, what it means for Kokanee fishing is anyone's guess. We are left with a few facts, as I see them, however:
1) Smooth Blades reflect the most light to the least amount of area at any given moment.
2) Hammered Blades reflect a lot of light to many areas, but not all areas.
3) Painted blades reflect the least light, but reflect light to essentially all areas at any given moment.
My hunch, is that painted blades are not very noticeable as plain metal when a lot of light is present (I.E. near the surface in any lake with this trait decreasing as you get deeper depending on water clarity). In these areas you have a lot of ambient direct light (I.E. the sun on a sunny day and clouds on overcast days) coming from the surface of the water. As you get deeper, the light still comes from the surface, but increasingly it also comes from the light reflected from the particles in the water itself. A metal surface in this case would be reflecting the light from all angles to all angles which would make it increasingly less noticeable. A painted blade won't reflect more light than a metal blade at these depths, but it will reflect a specific color of light. This will give you more of a contrast to help your bait stand out from the surrounding water.
So I guess to answer your 3rd question, painted blades, have an increasing advantage as you go deeper because they contrast (depending on color to an extent) more than a blade that simply reflects all light.
Once you get into color the whole thing becomes even more insane and I imagine the book DLM mentioned above gets into that more into that than I care to. I've read a similar book (What Fish See) which brought up several interesting points, but had a few flaws I won't get into. If I were ordering up a batch of spinner blades (actually I am putting in a hagens order very soon, I just can't finalize my list) I would put a nice mix of metal blades (both nickel/silver and brass/copper/gold) as well as several different colors of painted blades. Maybe even some glow in the dark blades.
If you're still reading this, than you have a lot of patience and probably think I'm a lunatic for thinking this much about spinner blades, but hopefully my theories at least make some sense to someone besides myself.
