As previously posted, Bill O'Neil of HiPo Parts has explained to me how the original paint on the needles of our gauges fluoresce best with light toward the high end of the spectrum, which is why the manufacturers used blue filters. But the blue filters cut down on the amount of light we get through - especially since most of them have gotten opaque. And, at the same time Bill says the fluorescent paint is pretty much dead within 10 years of being applied. In addition, Ford applied a white paint to the back of the mask that shields our eyes from the bulbs themselves, and the heat of the incandescent bulbs as well as dust and smoke has usually turned that white to brown - thereby reflecting even less light. So all of that contributes to really dim gauges at night.
And the question becomes how to get the gauges bright again for our night-driving pleasure. Toward that end I am planning a series of tests to see what can be done and what works best. And since there are several aspects to the issue (fluorescent paint, light color, light intensity, and reflectivity) it looks like the tests need to be well-planned and scientific. Here are some of my thoughts, but I would appreciate yours:
ENVIRONMENT: I'll set this up in the storm shelter in my shop where it is quite dark with the door closed. The test bed will be an extra instrument cluster, and I'll use my lab power supply set to 14.0 volts to ensure consistency. And I'll use my DSLR set on a tripod and put it in Manual mode so that the differing light levels will stand out. But, I should also put the camera in Shutter or Aperture mode for each test and capture the aperture or shutter speed the camera dictates for that shot as that will tell how bright the camera thinks the setup is.
PAINT: I have several NOS gauges, and it is possible that their paint will still fluoresce, so I'll give them a try. And I have gauges that barely have paint on them. So I'll use a combo of NOS, old, and gauges painted with Testors and HiPo paints to see what differences I can detect.
LIGHTING: There are actually at least five ways to approach getting the short wavelength blue light that will excite the paint:
Clear incandescent bulbs with good filters. This would basically put it back stock.
Blue-coated incandescent bulbs with no filters
White or cool-white LED's without filters. Bill has some new cool-white LED's that he thinks are the perfect solution for our instrument lighting and is to get me a set. But my understanding is that LED's produce a very narrow spectrum of light while incandescents produce a very broad spectrum of light. So there is a difference in our perception of how bright things are with LED's vs incandescents. Further, the filters will work differently on the light from those different sources.
White or cool-white LED's with filters.
Blue LED's w/o filters. I have this currently on Big Blue and don't particularly care for it as everything is BLUE.
MASK/REFLECTOR: My plan is to test one time with an old brownish mask and then with a freshly-painted one. But I don't see a need to test both of those in every combination.
I plan to test a cluster with un-painted gauges, clear incandescent bulbs, and old filters as a starting point, and then make incremental changes from there. But only make one change at a time.
What am I missing? What other lighting changes should be tested?
Gary, AKA "Gary fellow":
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Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI
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