Modeling the AT&SF - D&RGW Joint Line through Colorado Springs from Milepost 70 to Milepost 80 circa 1978-1979
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Post 27: Let there be light
"That's it," I said to myself, trying to lay track in the dark is not going to work. I need to get some lighting up first so I can see what I'm doing.
Fortunately I had already read a few modeler blog posts on how they used LED strip lighting on their layouts and watched several youtube how-to videos. Most of the blog and video examples I found worked with inexpensive (read cheap) strips of exposed LED chips in lengths of 5 meters (16 ft 3in) or less, with a color temperature of 3700K (similar to warm incandescent lighting) or 5000K (like bluish full daylight), and a CRI of only 8o or less (with 100 being perfect), and in many cases two side-by-side 12 volt strips were used to satisfactorily illuminate a layout, meaning they were not bright enough.
As a professional photographer I was already versed in color temperature (expressed in K for Kelvin), lumens (light intensity), and Color Rendering Index (CRI, how accurately a light source renders colors). I had already researched what is currently available and thought about how I might install it, and I had worked up a realistic ballpark budget, so it was time to bite the bullet and place an order for at least a first strip of LEDs to test out and a power supply to drive them.
I wanted something in 4000K neutral white, with a CRI of at least 90, that could light the layout with just one strip. That used to be a rather tall order, but not any more.
There's a new generation of strip lights called COB LEDs (Chip On Board) that pack way more LED chips and more lumens per foot, plus the LEDs are covered with a continuous flexible phosphor gel diffusing coating, meaning that the row of individual dots of bright light characteristic of LED strip lights is gone, replaced by a continuous ribbon of diffused bright light.
One popular brand of COB LEDs with a good reputation that people are using is Hitlights so I looked at them first. They make a high density model in 4000K, 90+ CRI, with 155 LEDs per foot producing 350 lumen/foot in a 16 foot strip.
Then I found another brand, BTF-Lighting. They offer a similar High Luminance strip using more powerful FCOB flip-chip LEDs with 148 LED/ft producing 596 lumen/ft. Plus they sell them in longer 10 meter rolls (32ft 6in), which makes them a bit less expensive per foot but considerably brighter.
Both options require a 24 volt transformer power supply, and not the simple black cube you just plug in the wall. Be sure to match the transformer to the wattage and amperage of your total run of strips as you may need to split your run and use more than one transformer.
Also, both COB and FCOB LED strips generate considerable heat, so mounting the strips on a metal heat sink is essential so you don't reduce their operating life. Both come with 3M peel & stick backing tape for this purpose. You can buy extruded aluminum channel designed specifically for the purpose, including a 45° version to wash both the layout surface and the back drop at the same time.
I decided to go with a cheaper alternative, 10ft long white-painted steel door & window drip flashing:
Once my test components arrived I quickly hooked them up. Man was it bright! Just holding the strip up with my arms stretched up and out I could see that this was going to make a world of difference. I got to work setting up a test installation so I could verify if a single strip would do the job I hoped it would, work out how high the strip should be mounted above the layout deck, how tall the valence should be, and how the LED rendered the color of the models.
I started by drilling and screwing an 8ft 1x2 on edge to the floor joists above Springs Yard (51in high) to which I could clamp (later screw) a 1/8in tempered hardboard valence. My first test used a 15in valence, putting the bottom edge 25in above the layout, with the front of the valence directly above the front edge of the layout.
I temporarily taped the LED strip to the canted flange of the drip flashing as shown above, and clamped the flashing along the bottom edge of the valence. Then I plugged the transformer in.
Voila! Let there be light!
What a difference. Both the layout deck and the sky blue wall backdrop were washed in neutral, even, diffused light. This was going to work! I left the test setup running as I worked on other projects, checking in on it from time to time to gauge my impression over time.
After a while I felt that it could be just a tad brighter on the deck of the layout, so I tried holding up some white reflectors to see if more light could be directed downward. The canted flange of the flashing blocks light from the upper back side of the valence, so painting it white would not make much difference. Same for adding a white surface fastened across the bottom of the joists. If anything, that would just bounce reflected blue off the backdrop downward, which I didn't want. The solution would be to either bring the light strip down closer to the layout deck, or add a second parallel light strip, which would double the project cost, something I don't want to have to to. That would also almost certainly be too bright, unless I used a lower output second strip.
So I took the test setup down and put up a deeper, 20in valence, bringing the strip light down 5in closer to the deck. I also addressed another problem: with the valence directly above the layout edge any models close to the front edge were dark and looked unnaturally backlit, so I moved the 1x2 forward 1 1/2in.
Both fixes worked. The overall light level on the deck was noticeably brighter, and objects along the front edge of the layout no longer looked backlit. But there was a new problem: the bottom edge of the valence was now at 71 inches, meaning my head would brush it if I leaned in at all. Reaching far into the layout to do any work, like laying track, would be a very tight squeeze. I'm going to have to go back up to an 18in tall valence (22in above deck, 73in above floor), which I think will also make for a more pleasing letterbox view. I'll live with that for a while to
see if I need to add a second, lower-power strip or not. Meanwhile I will have to temporarily mount the lighting much higher while laying track and putting in scenery along the back areas.
To complete the test I put out the building mockups along the yard to see how their shadows will look, along with a selection of different colored freight cars and locomotives to the judge the color rendition of the LEDs. I was completely satisfied on this score. The photos here have had no color correction done at all and look just fine. See what you think.
My take is the higher CRI, higher output FCOB LEDs are definitely worth the extra cost to me.

































