How to use CFL bulbs? at DVinfo.net

David Miller · January 6th, 2008, 09:55 AM

I would be very grateful if anyone could help me with a few questions about CFL bulbs as I have no experience of using them. I intend using them mostly as practical lights in regular sockets.

1) I will, at most, be using 85 watt bulbs. Am I right in thinking the sockets will need no protection (compared to tungsten photofloods which require porcelein sockets)?

2) I live in the UK. Is there anything important to note regarding the difference in electricity supply when using these bulbs? I think I will be buying from the US due to the greater selection.

3) Could anyone tell me how bulbs with lower CRI's actually look? I know a higher CRI is 'better' and renders colour more accurately but I am interested to know how a lower CRI CFL looks different, as it may be useful.

4) Finally, who are the best suppliers in terms of selection and price?

Cheers,

David.

Leo Versola · January 7th, 2008, 12:06 AM

Couple of quick responses:

1) Typically don't need any additional protection. If your practical specifies an 85w max for a tungsten, you're definitely OK for an 85w fluorescent. An 85w CFL draws about the same current and gives off the same heat as an 85w tungsten but gives off nearly 3 to 4 times the light output (250 to 300 watts).

2) Not sure about this...

3) I've read a few posts that flos with lower CRI's (around 85) are OK and there's not a significant difference to the bulbs with higher CRI's.

4) Again, not sure, but Google turns up a number of vendors and you might want to scour a few of the boards to see if there are any opinions.

Cheers,

Dave Dodds · January 7th, 2008, 12:23 AM

Rich Andrewski, who I always defer to regarding flos, can answer better. But as I understand it, a lower CRI yields a greenish cast. That said, I think in the mid 80's and up, it won't be a problem on video (film won't be as forgiving). Just remember to white balance. You can also pick up some minus green cards in various strengths to correct more if you need it.

Good luck.

~~Dave

EDIT: For the record, there's been talk about some manufacturers' bulbs being engineered to have a higher CRI in such a way that their output has been reduced somewhat. Something to ponder...

Simon Hunt · January 7th, 2008, 01:45 AM

Any lights you by from the US will probably be rated to operate on 120 volts and therefore will not work in the UK on 220 volts, they will fail immediately! You should look for suppliers in the UK that can get you CFL's that will work on 220 volt mains.

As far as CRI goes, yes a higher number is better. Lower numbers will either give you a greenish light or slightly magenta. This can work if the sources where you are shooting match either of these. Then when you do a manual White Balance everything will shift together. It's when you mix light sources and do a manual white balance that something will shift (color wise) in a strange direction. Most often we are using our own lighting to light faces of our "talent" and I believe it's always best to put the best quality light on their face, to make them look good! Do some shopping around to find the best you can afford in order to make the work you do look the best possible.

Simon Hunt
DOP & Gaffer, Film And TV

Richard Andrewski · January 10th, 2008, 11:01 AM

If you're wanting a green effect, try to go for anything under around 80 CRI. As you get lower into the 70s and especially the 60s, it really gets worse. I wouldn't buy anything in the USA as it will all be 110v 60hz. Better to try to find the sources you need in the UK (or at least within the EU).

January 6th, 2008, 09:55 AM	#1
David Miller Tourist Join Date: Dec 2007 Location: Edinburgh, Scotland Posts: 2	How to use CFL bulbs? I would be very grateful if anyone could help me with a few questions about CFL bulbs as I have no experience of using them. I intend using them mostly as practical lights in regular sockets. 1) I will, at most, be using 85 watt bulbs. Am I right in thinking the sockets will need no protection (compared to tungsten photofloods which require porcelein sockets)? 2) I live in the UK. Is there anything important to note regarding the difference in electricity supply when using these bulbs? I think I will be buying from the US due to the greater selection. 3) Could anyone tell me how bulbs with lower CRI's actually look? I know a higher CRI is 'better' and renders colour more accurately but I am interested to know how a lower CRI CFL looks different, as it may be useful. 4) Finally, who are the best suppliers in terms of selection and price? Cheers, David.

January 10th, 2008, 11:01 AM	#5
Richard Andrewski Major Player Join Date: Jun 2006 Location: Shenzhen, China Posts: 781	If you're wanting a green effect, try to go for anything under around 80 CRI. As you get lower into the 70s and especially the 60s, it really gets worse. I wouldn't buy anything in the USA as it will all be 110v 60hz. Better to try to find the sources you need in the UK (or at least within the EU). __________________ Richard Andrewski - Cool Lights USA - RED #114 http://www.coollights.biz

January 7th, 2008, 12:06 AM	#2
Leo Versola Regular Crew Join Date: Aug 2007 Location: San Francisco, CA Posts: 73	Couple of quick responses: 1) Typically don't need any additional protection. If your practical specifies an 85w max for a tungsten, you're definitely OK for an 85w fluorescent. An 85w CFL draws about the same current and gives off the same heat as an 85w tungsten but gives off nearly 3 to 4 times the light output (250 to 300 watts). 2) Not sure about this... 3) I've read a few posts that flos with lower CRI's (around 85) are OK and there's not a significant difference to the bulbs with higher CRI's. 4) Again, not sure, but Google turns up a number of vendors and you might want to scour a few of the boards to see if there are any opinions. Cheers,

January 7th, 2008, 12:23 AM	#3
Dave Dodds Major Player Join Date: Apr 2006 Location: New York Posts: 204	Rich Andrewski, who I always defer to regarding flos, can answer better. But as I understand it, a lower CRI yields a greenish cast. That said, I think in the mid 80's and up, it won't be a problem on video (film won't be as forgiving). Just remember to white balance. You can also pick up some minus green cards in various strengths to correct more if you need it. Good luck. ~~Dave EDIT: For the record, there's been talk about some manufacturers' bulbs being engineered to have a higher CRI in such a way that their output has been reduced somewhat. Something to ponder...

January 7th, 2008, 01:45 AM	#4
Simon Hunt New Boot Join Date: Jan 2007 Location: Vancouver, BC Posts: 24	Any lights you by from the US will probably be rated to operate on 120 volts and therefore will not work in the UK on 220 volts, they will fail immediately! You should look for suppliers in the UK that can get you CFL's that will work on 220 volt mains. As far as CRI goes, yes a higher number is better. Lower numbers will either give you a greenish light or slightly magenta. This can work if the sources where you are shooting match either of these. Then when you do a manual White Balance everything will shift together. It's when you mix light sources and do a manual white balance that something will shift (color wise) in a strange direction. Most often we are using our own lighting to light faces of our "talent" and I believe it's always best to put the best quality light on their face, to make them look good! Do some shopping around to find the best you can afford in order to make the work you do look the best possible. Simon Hunt DOP & Gaffer, Film And TV