What Kind of Gel?

D

DDirector

Veteran
The light is 2000K & +13 Magenta.
If shooting in 3200K, what gels do I need to put on a tungsten fixture?


Also,
I am shooting in a room that has a whole bunch of fluorescent lights. They cannot be replaced. And down the hall a door opens up and behind the door they are lit with 3200K tungsten lights, but in front is still fluorescent.
The lights behind the door that is lit with tungsten lights, I want them to be white.
The fluorescent lights, I would like it if they were blueish/cyan in tone instead of green. Would that be possible somehow? - Or can this be shifted in post?
If it looks bad either way, I will just keep it that green tone. It looks cool anyways.

----------------------------------------------------------------------------------

The other location has a mix of lights. One side is 3800K the other side is 2000K +13 Magenta (Sodium Vapor).
We want to balance the light to the 3800K for the key. But will balance for 3200K in camera/post for a slight blueish tone instead of white. The other light (orange - sodium vapor) will be the BG light. I may want to light the actors with a rim light as that colour.
 
Last edited:
if you are that far magenta, you need some plus green. Here is where it get funky though, cause I have had times that I was +10 and 1/8 plus green worked and times where 1/4 plus green worked. At that point I just sorta have the 1/8 and 1/4 and use and combine them to get the level of green you want.

I recently did a very similar thing on a music video where we had large amounts of flos in the ceiling and no time or budget to replace them all, and it worked very well.
 
J Michael said:
Lee Filters has a mired shift calculator you might find useful.
Click to expand...
This will definitely come in handy! But only if I know how to use it. Confused.
Sometimes the nearest value above seems like the correct gel to us and sometimes its the other way around. And there are sometimes 2 gels together, sometimes one. Help me understand how to use this.

What should be original source and what should be converted source. And whats nearest value above/below? And why are there 2 similar colours together in each category?

If I want to colour match that very orange light (2000K +13Magenta, is what is showing as white on my camera) If Im using a 3200K tungsten light, why is it GREEN gel I am supposed to add to it?
So, since its a 3200K light,
Original source is: 3200K
Converted is: 2000K
It says: 3/4 CTO + 1/4 CTO ~ So, why not just Full CTO? Confused.

Anyways, this will bring it down to around 2000K. And the Green is supposed to match the +13 Magenta hue?
If it is green I need, how do I calculate that?


If Im correct, this is a hi or low pressure sodium vapor light. The 2000K and +13 Magenta is what reading I was getting. Now, I can use the gels as stated above, but then again, there are apparently gels that are for Hi & Low Pressure Sodium Vapor. Or is is the exact same colours (orange & green) mixed into one gel?
 
Last edited:
You have a bigger problem than the usual CT conversion can cope with because if your source really is that far down in the magenta end, then there will be little at the bluer end in it, so attempting to colour correct it will probably produce very little light output.

CT orange tends to neutralise the the greenish spike from flu tubes - the more orange it is, the less light. I'm not quite sure where these magenta sources are?

You say you have tungsten and flu sources, and if they are the only light, I'd suspect the 2000K and magenta reading - it sounds very strange.

If there is lots of fluorescent lighting, it could be simpler to correct these, by wrapping the tubes, than trying to correct the individual tungsten sources. Sorting colour in post is fine when they are all the same temperature - but will have limited success if the light on the subjects varies. If it was me, I'd correct the flus, and shoot at 3200K - you can always warm or cool the entire thing in post if you wish, but mixing is bad news, and full CT of any type, Blue, Orange or green is a pretty light lossy process.
 
Are you using a meter to read the color temperature? If so be careful. They're designed for continuous spectrum sources, & are not accurate with discontinuous.
 
DDirector said:
I am shooting in a room that has a whole bunch of fluorescent lights. They cannot be replaced. And down the hall a door opens up and behind the door they are lit with 3200K tungsten lights, but in front is still fluorescent.
The lights behind the door that is lit with tungsten lights, I want them to be white.
The fluorescent lights, I would like it if they were blueish/cyan in tone instead of green. Would that be possible somehow? - Or can this be shifted in post?
Click to expand...

This one is a little easier to tackle. Dial your camera down in color temp below 3200 to, say, 2500 or less (different cameras have different basements on this setting) and the fluos will turn cooler. Then add CTO to your tungsten units behind the door until they read white. If you want to go cooler than your camera will let you, an 82 filter (at least a B, probably) will help, or just warm the tungsten up further and cool off the overall correction in post.
 
CharlesPapert said:
This one is a little easier to tackle. Dial your camera down in color temp below 3200 to, say, 2500 or less (different cameras have different basements on this setting) and the fluos will turn cooler. Then add CTO to your tungsten units behind the door until they read white. If you want to go cooler than your camera will let you, an 82 filter (at least a B, probably) will help, or just warm the tungsten up further and cool off the overall correction in post.
Click to expand...
2500K looks perfect. I tweaked a few Raw Pics I took, and that actually looks pretty good.

So, since the fluos will be 2500K and a blueish tone, when I use my 3200K Kinos for the closeups I can just match it to 2500K, or would it be best to match it to the existing fluorescent lights? - So, a green gel on the Kino?
 
No, the flos will remain the color temp that they always were, you are just shifting the image. To achieve white light for the hallway, you'll match the Kinos to the color temp you are shooting at (2500). If you are looking to match the cyan look of the flo's, then you will have to add CTB and plusgreen to the Kinos. You don't have to exactly match the gel package--whatever looks best to you. It's a situation where a well-calibrated monitor can really help.
 
CharlesPapert said:
No, the flos will remain the color temp that they always were, you are just shifting the image. To achieve white light for the hallway, you'll match the Kinos to the color temp you are shooting at (2500). If you are looking to match the cyan look of the flo's, then you will have to add CTB and plusgreen to the Kinos. You don't have to exactly match the gel package--whatever looks best to you. It's a situation where a well-calibrated monitor can really help.
Click to expand...
OH right.......... Wow. that took me a while to realize. Good you pointed that out.
But, I dont necessary need to add CTB though. If I have the tungsten Kinos, and I add "243 Fluorescent Green - 3600K" to match the fluos above, that should do the trick.

The kino and the fluos will be the same colour, so when shot at 2500K they both shift to a cyan/blueish tone
 
Last edited:
Here is a sample photo of what the finished product will look like.
These are my stand ins while we were on the location scout. Colour corrected to 2500K and added some contrast since it was flat, a little film grain, and desaturated the image (gave it a Bleach Bypass look).
Obviously with the actors.... Well, not really people (You'll see eventually and understand later) and with some additional lights (as this was shot naturally) that this will be epic. My best work thus far!

*With the compression on the forum the blacks look a little bit more crushed, like on his jacket. They are dark, but i can see some details
RECALL.jpg

I would like to confirm that this is the correct thing to do:
To match the colour of a tungsten light to the Sodium Vapour (2000K +13Magenta), I can put up the '651 Hi Sodium Gel' on the light and it should match that colour.
 
Last edited:
With the tungsten light being behind the doors of the fluorescent light in front, what gel would I need on the tungsten lights to be white?

Shooting 2500K so the green fluorescent lights give off a blue hue. But the tungsten needs to be white.
If I'm right, I need to throw on a 1/4 CTO on the tungsten and it should be fairly ideal to white?


...No, that's wrong. Ugh.
 
Last edited:
DDirector said:
If I'm right, I need to throw on a 1/4 CTO on the tungsten and it should be fairly ideal to white?
Click to expand...

No, the mired shift result is 88; the mired shift of 1/4 CTO is 63.

You're getting closer with 1/2 CTS, even closer with 1/4 CTS + 1/4 CTS, or 1/4 CTO + 1/8 CTO
 
You know you can just take the bulbs out from overhead and put them in your kinos, right? That way you don't have to deal with figuring out the perfect gel pack to put on your kinos to make them all match. If they're something pretty standard, you can rent additional tubes from a rental house for somewhere around $2 a bulb.

That is if you can't already find some in the place you're shooting (usually they'll have a box of spares on hand, if you're friendly with the location they'll let you use them.)

If you want hard light though, it gets a little more tricky, but at least thats a couple more sources you don't have to correct.
 
RyanT said:
You know you can just take the bulbs out from overhead and put them in your kinos, right? That way you don't have to deal with figuring out the perfect gel pack to put on your kinos to make them all match. If they're something pretty standard, you can rent additional tubes from a rental house for somewhere around $2 a bulb.
Click to expand...
While this can be done, "normal" 4' T12 lamps are 40w, Kinos are 75w. If using non-Kino lamps in a Kino fixture, the ballast should be set for 2' even if they're 4' lamps. If it's set for 4', you'll overdrive the lamps, causing a discrepancy in color.
 
RyanT said:
You know you can just take the bulbs out from overhead and put them in your kinos, right? That way you don't have to deal with figuring out the perfect gel pack to put on your kinos to make them all match. If they're something pretty standard, you can rent additional tubes from a rental house for somewhere around $2 a bulb.

That is if you can't already find some in the place you're shooting (usually they'll have a box of spares on hand, if you're friendly with the location they'll let you use them.)

If you want hard light though, it gets a little more tricky, but at least thats a couple more sources you don't have to correct.
Click to expand...
All of the bulbs are 8ft long. The only Kinos We have available are 4ft.
 
Most commercial flo's are pretty standard--good chance you can pick them up at Home Depot or a specialty store in 4 ft lengths, if you chose to go that route. At that point, you are just as well off adding the minusgreen.
 
So, I want to use the tungsten Flos, keep the bulbs and just adding a green gel to match the colour temp of the existing gels in the room.
 
That's what I'd do, anyway.

This is assuming that the existing flos in the room have a similar color temperature to the Kinoflos--depending on what flavor, they may read warmer or cooler (the latter is more likely). Be ready to add CTO/B as required. But as I indicated earlier--in this instance I wouldn't necessarily be mathematical about matching. You may prefer the skin tones to peg differently than the environment (i.e. less green, warmer/cooler etc).
 
You must log in or register to reply here.
Back
Top