Flourescent Lighting?

[Arne Johnson]

We're about to shoot a week-long documentary in a building that's all flourescents. It's going to be the height of summer with no air conditioning, so rather than do much lighting ourselves we'd like to replace all of their flourescent bulbs with color-balanced and higher quality bulbs. Kino-Flos are the high end choice, but anyone have a cheaper choice they've been happy with? I've also heard Kinos can be a little off in magenta if used in normal fixtures...Vitalites? Chromas? Soft Lights? commercial bulbs that are better?

Thanks,

Arne

[Shawn Murphy]

I too am trying to get the low-down on the various tube options, but as I don't know the answer yet, here's a snippet of a post from across the way that might provide a little info, however, I also don't know to what extent (if at all) the ballasts in those units will affect the output of the build choice:

From: http://www.dvxuser.com/V3/showthread...5&page=2&pp=10

"...I'm designing these around Kino's TrueMatch tubes, but you can also use any other 55w biax tube. An alternative would be Osram/Sylvania's StudioLine tubes... Gyoury uses those for their proprietary "wands". The primary difference in the StudioLine tubes vs. the Kino tubes is a tradeoff of CRI for lumens. I'll take the higher CRI over the higher lumens any day. The difference isn't dramatic on either side of the issue... both tubes are very bright and both have good CRI characteristics... it's just that the Kino tubes have about 5 points on the CRI scale and the StudioLine tubes are about the same percentage brighter. "

...and if you don't get the feedback you're looking for here, I'm sure you could pop over there and ask the question as well.

[Matt Gettemeier]

The above quote is from me... and I have to say that on further investigation that the CRI difference is more significant then I thought... and on top of it the Kino tube specs show them as being brighter too... so they're more pure (by about 8-10 points) and more output... by around 400-500 lumens.

I'll test this in real world situations to be sure that it's noticeable to the human eye (mine anyway)... but right now I don't see a reason to use any tubes other then Kino... unless of course it's budget.

Cash supply low? Then get the highest CRI tubes you can... it's easy to find tubes at 90+ CRI from many manufacturers... finding true daylight temps will be the challenge. I always find tubes at 4100k or 6500k... but rarely in the 5500-5600k range. Why? I don't get that.

The info I've found from Sylvania/Osram's own page shows the StudioLine tubes at 85+ CRI CLICK HERE and Kino Flo claims a CRI of 95-96 CRI on their tubes... If you gotta' replace a whole grid of tubes then I understand seeking alternatives... but for a few fixtures I'd go with the sure thing. (They last for years.)

[Lamar Lamb]

I've only been doing this video thing for a year now so this may sound dumb but if the lighting is ok and the only thing wrong is the color temp why would white balancing not work. Are the exisiting bulbs of several different color temps? Not trying to be smart, mind you. I'm just trying to learn.

[Arne Johnson]

Lamar,

I'm no expert on lighting either, but from what I understand there's a couple issues...Flicker and color temperature. And I don't think white balance solves the whole thing. With these nicer bulbs I think you can mix better with available light (coming in from windows, etc), and choose the color temp-look you want. I've heard other people say you should just white balance, but we have in flourescent settings before and it's still a different look than outdoors or other kinds of indoor lighting. Would be nice to have a little more control over how skin tones will look and all that. I suppose if it were all just about white balance, no-one would use anything but cheap flourescents.

Arne

[Dan Vance]

Originally Posted by Lamar Lamb

if the lighting is ok and the only thing wrong is the color temp why would white balancing not work

The spectral output of Fluorescent lamps shows sharp spikes at certain wavelengths, the most troublesome being in the green region. When a lamp has a low CRI, its stated color temperature is just an approximation, because the spikes make it impossible for it to have a true single color temperature. If you put a low CRI 4100K fluorescent next to a "pure" 4100K source, you would see a significant color difference, which would probably appear as a greenish cast. You can't really white balance a low CRI source (fluorescent or otherwise), because the lamp lacks the full specturm of colors needed to balance it. You can see the worst-case example of this with low pressure sodium lights. They emit only yellow and orange light, so no amount of white balancing or filtering can correct them because there is no green or blue light coming from them to work with.
Generally a lamp with a CRI over 90 is considered a match to a reference source of the same color temperature. That is, a 4100K or 6500K fluorescent with a CRI above 90 can be satisfactorily filtered (gelled) to 5500K or 3200K, or if the fluorescents are the only source, white balance is then an option.
So, getting back the original post, you can use the cheapest fluorescents you can find that have a CRI above 90 (which may be the Kino's), use the same type in all fixtures, and then treat them as you would any source with a known color temperature.

[Arne Johnson]

Thanks Dan, that really clearly explains what I had suspected...After reading your post, we found a couple flourescent lamps above 90 CRI that are a bit cheaper then Kinos, for those who are interested:

http://www.fullspectrumsolutions.com...e_lights.shtml

http://www.naturallighting.com/store...?&parent_id=72

They should help, no?

[Lamar Lamb]

Ok, I have quite a bit of experience in gamma spectroscopy and this sounds about the same except at a lower energy level. So basically there are noticable peaks at given energy levels in a low CRI bulbs spectrum whereas a high CRI bulb has a flatter or more linear spectrum? What does CRI stand for?

[Shawn Murphy]

'Color Rendering Index', basically it represents the level of accuracy for a given color/temp rating.

Here's a link I found from another, it contains a lot of relevant info and further detail on CRI:

http://www.gelighting.com/na/busines..._rendering.htm

[Carlos E. Martinez]

Originally Posted by Arne Johnson

I'm no expert on lighting either, but from what I understand there's a couple issues...Flicker and color temperature.

There won't be any apparent flicker with these new lamps, if shooting at normal speeds (shutter).

Color temp is a different thing, but if shooting video it's easier to WB that. But there are some limitations, so if you want absolute precision and a total integration in your light color hues then fluos might not be the way to go.

And I don't think white balance solves the whole thing. With these nicer bulbs I think you can mix better with available light (coming in from windows, etc), and choose the color temp-look you want. I've heard other people say you should just white balance, but we have in flourescent settings before and it's still a different look than outdoors or other kinds of indoor lighting. Would be nice to have a little more control over how skin tones will look and all that. I suppose if it were all just about white balance, no-one would use anything but cheap flourescents.

Light hue differences are mostly apparent when you mix light sources.

In my practical opinion, as I have been using several of these new light fixtures on a recent doc, they are great. I like that mix of color hues, because it makes most shots more interesting.

They are a long shot from traditional/green cast/flickering fluos, which were only useful on industrial settings or large spaces that you could do nothing about. Video WB made a reasonable look, but you still had to light specific spots and color correct in post.

Skin tones look fine with these new bulbs, and because the light is very diffuse "right out of the bulb" you get nice close-ups. The fall-off of fluos also help make the background darker.


Carlos

[Jason Brunner]

In many cases I have been faced with situations where it is simply impractical to correct all the flo in a location, and impractical as well to turn them off and light the whole area( a supermarket, for example), so here is my little trick:
I use the existing flos and supplement with Kinos, and/or small HMI's
as front fills and back lights to counter the typical top down feel of typical flo installations, then, (and here's the little trick) I correct my kino's and HMI's with plus green gel, to match the green of the existing light, so all my sources have the same ambient amount of green. You can then white balance out the green quite effectively, or correct it in post, but in both cases you achieve a uniform correction.

[Shawn Murphy]

Jason,

Just curious, what brand of small HMI's do you have and use in these scenarios?

[Gints Klimanis]

>Cash supply low? Then get the highest CRI tubes you can... it's easy to find >tubes at 90+ CRI from many manufacturers... finding true daylight temps will >be the challenge. I always find tubes at 4100k or 6500k... but rarely in the >5500-5600k range. Why? I don't get that.

After spending a lot of money on two cases of 95 CRI (Osram) 48" T8 $5 and $8 bulbs , I found Philips Colortone T12 (C50) 5000K, 92 CRI selling for $100/case of 30 at Home Depot. You just break out the case and get a great deal. The very same bulb is individually packaged across the aisle for $5.97. Any of these bulbs are horrible on my aquarium, but they are fantastic in my video studio,
which is my martial arts training room in my garage. I also fitted another
dojo with 48" ($3) and 96" ($8?) Colortones (also from Home Depot), and they mixed well with daylight and flash.
Though, I did cover the camera flash with a plus green gel from Nikon.
The windows were too big to cover with Roscoe plusgreen sheets.

Gints