Fluorescent DIY? Also CRI/color temp questions. Help! at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Photon Management

Photon Management
Shine an ever-loving light on you.


Reply
 
Thread Tools Search this Thread
Old May 17th, 2003, 10:54 AM   #1
Major Player
 
Join Date: May 2003
Location: St. Louis, Missouri
Posts: 936
Fluorescent DIY? Also CRI/color temp questions. Help!

Well kids I'm late for work now, but it's starting to look like I may put my Arri, Mole, or Rifa purchases on hold. I know we always hear horror stories from DIY attempts but I'm getting seriously tempted to make my own fluorescent fixtures.

Every fluorescent set I see is very high dollar. Some years ago my brother bought a little fluorescent work light from Costco and I couldn't believe how nice the quality of light was from this little $20 gem...

Thanks to another nut who pointed me in the direction of investigating "natural lighting" I've found companies that sell 5500k and 5000k tubes with 96 CRI !!! My question is this, they claim that 5600k is noon day sun and 5000 is slightly warmer. I haven't found ANY fluorescents even close to the 3200k we see in some fresnels UNLESS they have a CRI of about 82 which is basically unusable for real quality.

So 5000k with CRI of 96? Wouldn't that be a SUPERB bulb? You can also find top grade electronic ballasts to regulate the bulbs and assure(?) flicker free performance...

So here's the deal... either give me some reassurance or BURST MY BUBBLE!!! I don't care which... I want intelligent discouragement if you can offer it...

FYI, I am very handy and resourceful... I will be able to build professional looking lights, so that is not the issue. Thoughts?
Matt Gettemeier is offline   Reply With Quote
Old May 17th, 2003, 03:57 PM   #2
Major Player
 
Join Date: Apr 2002
Location: Lewisburg PA
Posts: 752
You can buy the Kino Flo tubes at 3200 K from B&H for about $25 ea. These are the same used for Kino Flo fixtures.
Peter Wiley is offline   Reply With Quote
Old May 18th, 2003, 01:38 AM   #3
Wrangler
 
Join Date: Jun 2002
Location: Vancouver, British Columbia
Posts: 8,308
Thought:
How many 40w 4' long flourescent bulbs does it take to equal the light from a teeny tiny 600w Tota light?

Answer: too many, unless you have unlimited space or a studio where they could be mounted overhead.
You could use an electronic VHO ballast, which runs 110w 4' bulbs, but you are still looking at 6 4' bulbs to equal a small Tota. Plus I think a VHO ballast is more expensive than a Tota, not including the bulbs.
__________________
Need to rent camera gear in Vancouver BC?
Check me out at camerarentalsvancouver.com
Dylan Couper is offline   Reply With Quote
Old May 18th, 2003, 06:01 AM   #4
Inner Circle
 
Join Date: Oct 2001
Location: Honolulu, HI
Posts: 2,053
I use a Lowel Totalight in a Chimera and DP lights with very good results, unless it's a matter of balancing daylight. Then there's some real hurdles to clear.

The problem with tungsten lights become significant as they're way too warm with very little energy in the shorter wavelengths (I have a spectrophotometer which actually reads this stuff).

Most of the energy they spew is in the lower frequencies. To get them to match daylight you have to attenuate (absorb or chop down) the reds and yellows -- and unfortunately tungsten lights emit most of their energy in that part of the spectrum. The CTB gel will leave just that part of the spectrum which will allow for a close daylight match, and there's not much left after that. To our eyes a full CTB appears dark blue and loses a full 1.6 stops. That means a lot of the energy of a tungsten light gets wasted.

HMI's or daylight fluorescents provide a spectrum that is much closer to that of daylight, requiring little filtering to match. Thus, most of the energy they emit is usable. Maybe a bit of green has to be filtered from some fluorescents, but that's a fairly narrow band. The gel capable of doing that looks light pink to the human eye.

I used 5000k Phillips Colortone lights in a Lowell Light Array which worked nicely to balance daylight.

I'm starting to experiment with some cheap worklights with some slight filtration that look very promising.

Dean Sensui
Base Two Productions.
Dean Sensui is offline   Reply With Quote
Old May 18th, 2003, 08:47 AM   #5
Major Player
 
Join Date: May 2003
Location: St. Louis, Missouri
Posts: 936
Dylan, I'm going for a different quality of light. Originally I decided on a Rifa in one of the larger sizes, but then I started to look at the fluorescent "arrays" as a possible alternative to a softbox. A softbox is obviously also a lot bigger then a tota... but it's for a different lighting approach.

It's been pretty hard to nail down the EXACT lumens on the tota with a 600w tungsten halogen bulb, but it has to be between 9000 and 12,000 lumens for certain. The average lumens I've been able to find for a 500w is 8500-9200 and the average I've found for a 1000w is 20,000-21,000... so I just added 20% to the 500w... if you have definite data to the contrary I'll happily accept it, but it took me 20 minutes of searching just for this so I didn't want to make a day of it... figure 12,000 max and it keeps this simple.

The beauty of the fluorescent system is naturally diffuse light and cool operation... also if you can find a way to do it, and I will, you can build a flat panel type case that is easy to transport and set up. What I always liked about the Kino Flo (and other) systems is how you just open the case, put it on your stand, plug it in, and aim. EASY! The downside is the cost... so here I am. I seriously considered keeping all this info to myself because I hate my job and if I have any kind of success with this project I'll build 'em and sell 'em... maybe one of you guys can test one for me for some feedback... do I sound excited? I am... here are the facts...

Keep in mind the luminosity info I already have above.

Studio Supreme PL36 is a 16" long bulb with a color temp of 5500k and CRI of 96 with a lumens of 2400 at 36 watts... not bad. 4 of them in an array would be a close match to the 600w tota with softlight and the bulbs are only 16" long. Interesting? Next!

Studio Supreme PL55 is a 22.25" long bulb with a color temp of 5500k and a CRI of 96 with a lumens of 4800 at 55 watts... now we're talking an array of only THREE bulbs with an output on par with 750w openface lights... as a softbox at a cool running 165 watts... what do you think now? Bored with this yet?

I'm going to do some more investigation, but I just wanted to let you guys know where I'm standing on the issue. Kino claims a color rendering index of 95 across the board on all their lights...

Please keep expressing your thoughts on this! I appreciate your help and input Peter, Dylan, and Dean! Anybody else who reads this feel free to offer any insight you may have...
Matt Gettemeier is offline   Reply With Quote
Old May 18th, 2003, 09:04 AM   #6
Major Player
 
Join Date: Sep 2002
Location: Belgium
Posts: 804
Agree Dean, but tungsten lights are the most uniform in spectrum quality, indeed steadely going up towards the lower freqs. If you have a photospectrometer available you must also agree that fluorescents in general, and even the "daylight fluorescents" don't have a smooth emission spectrum.
Andre De Clercq is offline   Reply With Quote
Old May 18th, 2003, 12:06 PM   #7
Wrangler
 
Join Date: Jun 2002
Location: Vancouver, British Columbia
Posts: 8,308
Matt, I know you are looking for a diffused light, when I mention the Tota, it's because besides putting a soft box on a Tota, you can reflect the Tota against an umbrella, use it through an umbrella, or even just put diffusion paper in front of it. Lots of very small, compact ways of making it a diffused light.

I've used Kino-Flos on several occasions. They are great. Nothing bad to say about them except for the price they are a total rip-off, and very are bulky. Sure they fold up into a nice case, but I could put a tota light in my pocket.

My advice is to go for it. Build a flourescent kit, give us your feedback. I'd love to see a direct comparison. If you do, I suggest looking at compact flourescents, or short bulb VHO flourescents. They put out considerbly more light than a regular lamp, and although require a more expensive ballast, will keep your lights from getting oversized.
__________________
Need to rent camera gear in Vancouver BC?
Check me out at camerarentalsvancouver.com
Dylan Couper is offline   Reply With Quote
Old May 18th, 2003, 12:24 PM   #8
Major Player
 
Join Date: May 2003
Location: St. Louis, Missouri
Posts: 936
I appreciate your suggestions Dylan... take a peek at my post above. I've had some great luck in finding compact fluorescents...

BTW I'll still have a tota or two. They are great for portability, effectiveness, and price.
Matt Gettemeier is offline   Reply With Quote
Old May 18th, 2003, 02:05 PM   #9
Major Player
 
Join Date: Dec 2002
Location: Northridge Ca
Posts: 734
Matt

Go to creative cow.net. Go to the lighting design forum. There you will find some discussion of fluorescent work lights from a company called "Lights of America." At least two people are working on a professional version of these lights.

Don't quit your day job.
__________________
Wayne

If it was easy, they'd get a relative to do it.
Wayne Orr is offline   Reply With Quote
Old May 18th, 2003, 08:18 PM   #10
Wrangler
 
Join Date: Jun 2002
Location: Vancouver, British Columbia
Posts: 8,308
<<<-- Originally posted by Matt Gettemeier : I appreciate your suggestions Dylan... take a peek at my post above. I've had some great luck in finding compact fluorescents...
-->>>

Damn, I must be getting old. I read your post the first time, but it didn't sink in. Maybe it was just early in the morning and I didn't wake up yet. Yeah.... That's it!
__________________
Need to rent camera gear in Vancouver BC?
Check me out at camerarentalsvancouver.com
Dylan Couper is offline   Reply With Quote
Old May 18th, 2003, 08:52 PM   #11
Inner Circle
 
Join Date: Oct 2001
Location: Honolulu, HI
Posts: 2,053
Andre...

You're right about the lack of smoothness in spectrum for fluorescents.

When I get a chance, I'll get a reading of natural daylight, daylight fluorescent and halogen and post 'em somewhere.

If I recall, fluorescent has some sigificant spikes and a few gaps.

Dean Sensui
Base Two Productions
Dean Sensui is offline   Reply With Quote
Old May 18th, 2003, 09:02 PM   #12
Wrangler
 
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,543
<<<-- Originally posted by Wayne Orr : you will find some discussion of fluorescent work lights from a company called "Lights of America." -->>>

That's pretty funny. They sell the "Lights of America" brand flourescent shop lights at Home Depot. I have bought quite a large quantity of these twin 48" fixtures, maybe 50 or even more? We used them to light our scenery storage warehouse. They are very inexpensive, but the quality is total crap. A number of them turned up DOA, and they are very easily broken. For my application (providing minimum visibility in a 23,000 sq ft windowless warehouse) they're OK, however if I were doing it over again I would probably spend a bit more and hope for better quality. You get what you pay for. I certainly wouldn't use them for any application where you're moving them around. They're just too fragile.

Oh yeah, the most amusing thing is that as I recall, the "Lights of America" are made in China...
Boyd Ostroff is offline   Reply With Quote
Old May 18th, 2003, 11:39 PM   #13
Major Player
 
Join Date: May 2003
Location: St. Louis, Missouri
Posts: 936
Thanks everybody... at this point I've been off and on the computer all day. Every time I think of something new I get back on again to check it out.

Lights of America has nothing right now. They are even classifying CRI's around 86 as photo quality while everybody else has bulbs at least 91. Also their production light thing is vapor-ware right now. I wish it was otherwise but as of now it's only rumors with a possible release this fall of something for a/v... and I haven't found anything to verify that it's more then just rumors.

The best electronic ballast is a Lutron Hi-Lume but it's really high. Also it's not really SIGNIFICANTLY better then the two runners-up which is a Sylvania (Pho-Dim) aka Quicktronics aka Helios T5/HO... Sylvania bought out this division of Motorola... the other ballast is the Magnetek Mark VII... both the Sylvania and Magnetek are very close together and pretty close to the Lutron... Lutron just has the best reputation for uncompromising quality. All these ballasts have the lights at a 25Khz to 40Khz cycle so they'll function just like the pro ones in Kino's etc. I'd wager that if you got one of those apart this is what's inside.

I haven't got the actual "fixture" problem worked out yet, but I will... as soon as I do I'll put one together in no time, then I'll have to try to post something up or I'll post a link so you can see the madness.

I looked into Softlights T5 bulbs and they have a worse color spectrum graph then the Kino's or the Supremes that I mention above... also they make no mention of the CRI value on their bulbs... hopefully somebody can correct this issue otherwise I see no reason not to use one of the first two brands.

The ballasts I suggest here are dimmable... so you can put on a PROPER dimmer and have variable light output (if you use the wrong dimmer you will short out the system so CHECK)... the benefit of variable light output is that if you are using a daylight balanced bulb and getting over 10K lumens you can dim it down and pull the color temp closer to tungsten, albeit with uncertain results...

To be honest I question wether or not all this B.S. is worth it, but I'm accustomed to doing things the hard way. If you guys enjoy the little dog and pony show then it's worth it... and if this works out well then it should prove to be a worthy project for somebody else since I'll have done all the research and experimenting.

Thanks for all your feedback guys.
Matt Gettemeier is offline   Reply With Quote
Old May 19th, 2003, 12:39 PM   #14
Wrangler
 
Join Date: Sep 2001
Location: Tickfaw, LA
Posts: 1,217
You may want to be careful about dimming the bulb. What some users have recommended is build your lighting rig in banks and switching the banks on and off as needed.
__________________
Nathan Gifford
Southern Cyclist Magazine & Productions

For quick answers try our Search!
To see me and Rob Lohman click here
Nathan Gifford is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Photon Management

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 10:56 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network