I have 55W 3000K globes that use the standard size ballasts in my D4 and the light is visibly yellow, both when looking at the lights and the light on the ground. I subsequently purchased 35W 3000K globes with slim-line ballasts for my tractor and the 1st set of globes produced quite a green light on the ground whereas other 55W halogens produce the usual yellowish light. Replacement 3000K globes (with a slightly differently manufactured base) produce a less green light but still shows quite green on the ground compared with with the halogens. The comparisons are done through the open door so as to eliminate any tinted glass distortion.

Because of the different wattage, I'm not inclined to try a 35W globes on a 55W ballast although I suspect I could try the 55W globes with the 35W ballasts.

I have read that older ballasts were DC whereas newer ones are AC so differences in ballasts may be causing the colour differences. Has anyone encounted different colour results, especially 3000K, from different types of ballasts?