On a bulb, there might be a number such as F32T8/TL741 but what does the numbers mean?
- F32 means it is a 32W bulb.
- T8 gives the size (T8 is a 1" diameter tube).
- 7 - I'm not sure what this means.
- 41 means the color temperature is 4100 Kelvin.
- 2000 K is like sunset/sunrise
- 3000 K is warm yellow light
- 4000 K is a warm white light like early day light (has a bit of yellow)
- 5000 K is also daylight and is a good option for a garage.
- 6000 K gives a noticeable blue tinge.
What the number doesn't indicate is the brightness (i.e. Lumen) or the color rendering index (CRI).
When it comes to lumen, the right number depends on what the area you want to light up. A 60W incandescent bulb is about 700 lumens. Putting a 5000 lumen light in your bedroom will be too bright and harsh but it might be just right for a 2 car garage.
The CRI is a number from 0 to 100 where 100 gives the best color reproduction on the object while a 1 will make everything look like a single color.