Both 3000K and 4000K are still on the warmer side of the Kelvin scale as LED light fixtures can still reach 4800K 5000K and up to 6500K color temperatures.
3500k vs 4000k light. Which is brighter 4000k or 6000k. 2700k 3000k 3500k and 4000k. Just an observation Im sure there could be other reasons.
However household lighting temperatures will come between 2700K to 4000K. Candlelight has a color temperature of about 1800 K and the light that comes from it is yellow soft and warm. I use 6500k floros for vegging and have in the past used hybrid conversion bulbs that were in the 4500-5000k range with great.
If the light will be used at night and in the wild the lower blue content of the 3500K is a better choice for the environment. It should be less likely to attract insects when compared to the 4000K. 4000K LED lights can be used very effectively in retail office and certain areas in a residential application.
Please take these color temps with some broad strokes and dont worry about minor tint either there will be variations as these are in different lights. It is not. 4000K is slightly less cool or less white than a 5000K light.
3000K will carry more of a yellow tint to it but still can function nicely within a wide range of applications. A mid-way 3500-4000K start-to-finish is a good balance of the two. So for these autos the combo works really well.
Cool white light contains more blue light and looks brighter to the eye this is why cool white bulbs have a higher lumen output when compared to the equivalent warm white bulb. Its that perfect blend of the two. As Autumn got more brown though I had to switch for.

