Proper Radiant Power (Watts) for Vray Lights

[kosso_olli]

When I type in the value of 100 Watt as Radiant Power in a vray light to simulate a 100W light bulb, I get blown out areas. Recently I found out why that happens in the vray help file:

"Keep in mind that this is not the same as the electric power consumed by a light bulb for example. A typical 100W light bulb only emits between 2 and 3 watts as visible light."

Seriously, do I need to calculate the percentage of the visible light of a 100W light bulb (2-3 Watts)? Honestly, I dont care about which amount gets lost as heat radiation.

I just want to type in 100 Watts in the vray light, and it should be nearly as bright as a true light bulb would be, and not blown out.

Regards

Oliver

[vlado]

You should be using the Lumen values of a light bulb, not its electric power. The Watts are mostly useless if you don't know the efficiency of your light bulb - two light bulbs might be 100 W but produce wildly varying illumination.

Best regards,
Vlado

[Macker]

I work with the rough figure that a 100w incandescent bulb would be around 1500 to 1800 lumens, and between 2800 and 3500 kelvin.

[tricky]

Seriously, do I need to calculate the percentage of the visible light of a 100W light bulb (2-3 Watts)? Honestly, I dont care about which amount gets lost as heat radiation.

I know what you mean. It is something we have just got used to over the years. Perhaps Vray should come with some preset light levels for 'typical', known bulbs? A Tesco 50W bulb for example, or an Asda 7W low energy bulb...

[ajroane]

I know what you mean. It is something we have just got used to over the years. Perhaps Vray should come with some preset light levels for 'typical', known bulbs? A Tesco 50W bulb for example, or an Asda 7W low energy bulb...

It's better to have fewer presets built in to the program. They would only add clutter and never get used by most artists. Look at the templates in the Max Photometric lights, maybe those presets will help you out.

Regards,
Andrew

[vlado]

I know what you mean. It is something we have just got used to over the years. Perhaps Vray should come with some preset light levels for 'typical', known bulbs? A Tesco 50W bulb for example, or an Asda 7W low energy bulb...

Well, those would be very very specific to a certain place. We have no Tesco and Asda bulbs in Bulgaria; the ones that we do have are probably not available in the US and so on.

Best regards,
Vlado

[tricky]

Well, those would be very very specific to a certain place. We have no Tesco and Asda bulbs in Bulgaria; the ones that we do have are probably not available in the US and so on.

Best regards,
Vlado

I was only joking Vlado!

[tricky]

It's better to have fewer presets built in to the program. They would only add clutter and never get used by most artists. Look at the templates in the Max Photometric lights, maybe those presets will help you out.

Regards,
Andrew

For newcomers (and experts alike), presets are a very useful tool. We regularly use presets (in many programs) as a starting point, and adapt from there. Reinventing the wheel isn't always the best use of your time.

As I said though, knowing what settings for Watts and Lumens to use really comes with experience. Watts is one of those values that you soon realise is pretty useless as a comparison to real world bulbs.

[Neilg]

Light bulbs actually say the lumens on the box. If you're getting that specific where bulbs are being picked out for you (and seriously, you NEVER need to be that exact) then the information is available.
Most have the exact colour on the box too, although not all. Like so:



But lets be honest, who cares. If it looks right, it is right.