DBT Lighting - The Trials

I have been undertaking some experiments with lighting the Dutton Bay...

Four different lights

Above we see, clockwise from top left: 2700 degree "incandescent rated" fluoro tubes, standard cool white fluoro, regular 100 watt "spot" lights, and 5500 degree "Daylight" fluoros. The band of darkness in the background is simply a curving backdrop which was not illuminated properly. Photography was with an Olympus digital camera with the white balance set to Automatic - although there is not a lot of indication that had too much effect. You can make your own decisions (or help me make mine) as to the best lighting.

And now the history of lighting the shed.

When the lights were installed in the shed I opted for Philips Super80 TLD 827 tubes, which have a reasonable light spectrum, and a colour temperature of 2700 degrees. This is meant to match incandescent lighting, and was felt to be desirable considering the original parts of the layout were built to be exhibited under that type of lighting.

Over time, as the preliminary stages of construction have been completed, I have become concerned about these lights. Photos taken with similar filtration to that employed succesfully with incandescent lights have been tinged with brown, and I don't think the amount of light being thrown on the layout is sufficient either.

So, in November 2000, with the help of my friend Leo Kennedy, I constructed a temporary lighting valance, and clamped it above a couple of modules. This valance is of sufficient length to hold two 4' long fluoro fittings, allowing side by side comparison of the different types of tubes. The results are still being evaluated, but here is the first of the comparisons.

Note that all of these tests were performed with the backdrop being plain white - in fact that is the primary reason for the timing of this test, as it makes sense to paint the sky on the backdrop after the colour of the lighting has been established.

Setup


Here is the setup - the temporary valance is pretty basic, using an L-girder which turned out to be warped, with two lengths of 3x1 screwed in as legs. These area simply clamped to the modules. You will notice another piece of 3x1 clamped across the front. This timber allows me to use the test rig for another purpose - determining the best height (or depth) for the valances when they are finally built. The aim is to avoid seeing the top of the backdrop, thereby removing another possibility of spoiling the illusion.

2700 vs Cool White


This quite obviously has the 827 tube on the left, while the tube on the right is a standard Cool White. See the distinct blue tinge - that surprised me. I was expecting my tests with daylight rated tubes to be a blue colour, but not the cool white. It must be noted that the strong colours are located at the extremity of the fluoro tubes, where the lighting srtength is diminished. When the lighting valance is completed there will be continuous lighting throughout, and these coloured "edges" will be virtuslly non-existent.

In the image above, the eye tends to be distracted by the obvious colours on the white backdrop. A better test is to check out the greenish grass, the white salt piles, and the whitish gypsum...


See the differences. On the left, under the 2700 degree lighting, the salt has a pinkish tinge, but (to my eye) the grass looks fine. On the right, under the "cool white" lighting, the gypsum looks nice and white, but the green grass doesn't look too good at all.

I obviously have some decisions to make here - next time we shall simply reverse the fluoro tubes so we can see exactly the same scene under the different lighting.

Stay tuned for further comparisons with daylight tubes. The pictures have been taken - all I need to do is work on publishing them.

Last updated 16-Nov-00

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