Gels - What are they and Why would I want some?

Silverlake · #1 08-04-2006, 01:30 PM

We get asked this question on a regular basis so I thought I would put something together.

Gels are gelatin filter sheets used over light sources to either correct the light balance or create dramatic lighting effects. They are also used to change colors of backgrounds and there are diffusion gels to help with diffusing light. Gels can be taped to a reflector or placed in frames and mounted to the reflector or light source.

Here is an example of a reasonably neutral background without gels and then with each of the gels included in the Bogen Vivid Color pack.

As you can see, if you are limited on backgrounds and are interested in matching outfits to your backgrounds, gels can be a great way to accomplish this. I intentionally did the samples with a hot spot in the middle and tapering out to darker colors. You can get different intensities of color depending on how you expose the gelled backgrounds in relation to the exposure value of your subject.

The only trick in working with gels is to keep your main and fill lights from spilling on the backgrounds and contaminating the effects of the gel on your background light. You will never get true, vivid colors if your main and fill are washing out the effect of the gel.

Obviously, you can mix two gels together if you have two background lights or stack them to achieve the combined results of the two colors.

Hopefully, this will prove helpful to some of you.

fdpiech · #2 08-04-2006, 01:48 PM

I love using gels. Not only can you use them on a neutral backgound... you can use them on ANY background.

I've seen some really great effects on some TV shows where the guest they are talking to is sitting in the white light and they have washed the room behind them with a geled spot...

You can do some really cool stuff this way.

Twila Davis Reed · #3 08-04-2006, 06:15 PM

Yup, I use gels too...they're a lot of fun! Not only on the backgrounds, either!

KariR · #4 08-04-2006, 07:49 PM

Travis, that is AWESOME!! I have a bunch of gels that I got from Alien Bees and I played with them once when I first got them. I could only seem to get part of the backdrop and at the time didn't know about using my grids for stuff like this. Is that what you used to get that hot spot and then fanned out appearance or a vignette look on these? Did you just put the gel over the grid? I LOVE that look and mine NEVER turned out like that! You got great vivid color!! My color was not showing up very well and then I tried to use them another time and you couldn't even see the color! So thanks for stating that if your main and fill are on the drop then you won't get that vivid color. That totally explained my problem. Now it makes me want to dig them out and play a bit with them again! And where did you have your backdrop light positioned for these shots travis? Did you use just one? Thanks. Sorry for all the questions, iquiring minds want to know!

Oh and another question, can you use these with softboxes or octaboxes? Probably not but just inquiring. I know that you can mix them and I would like to figure out the look that would imitate candle light. I have a few neat ideas for christmas pictures and want to have that kind of light. So how do you guys use your gels on main lights without being able to diffuse it for hotspots and a nice lighting?

Thanks!

Twila Davis Reed · #5 08-04-2006, 10:20 PM

Kari, I've had good luck with clipping them onto the inner baffle panel in my softboxes. It's more subtle that way, but it gives better coverage than taping or clipping them outside. For my background light, I generally use one of my honeycomb grids and then clip the gel around the front with some of the little plastic clippie thingies that came with my Alien Bees...

Oh, and remember, candle light is slightly contrasty, so you probably wouldn't want too much diffusion unless you're trying to make it look like there's a big bank of candles. Sounds like fun to experiment.

Silverlake · #6 08-07-2006, 03:00 PM

Kari,

The biggest mistake most people make with gels is washing out the color with their main and/or fill lights. That will give you a normal looking background with maybe just a touch of color close to the background light.

For these shots, I just used a parabolic dish over the strobe and taped the gels to the front of the parabolic. They are 12 inches square. You can use them in conjunction with soft boxes, but you want to make sure the light source is completely covered with the gel. If you are letting white light escape around the gels, it will severely diminish your color saturation.

These examples were done with bogen "vivid Color gels". They also make sets that are less punchy, but designed to correct for tungsten, fluorescent, and other color shifts. These can be used for more subtle effects.

Travis

KariR · #7 08-07-2006, 09:19 PM

Thanks twila and travis. Twila, I would love to just play around now and see what I can come up with! I put my gels away cause I was frustrated cause I wasn't getting the color that I thought I should be getting. NOW I know why! LOL!

Travis, pardon me if this is a stupid question, BUT.... what is a parabolic? Is that another name for the reflector cone that comes with Alien Bees? I believe my gels are 12 in too. Or they have to be close. I have a HUGE set of them. So there are ALL different colors in there.

Another question if you don't mind and others might want to know the answer to this also. Will the color of the gel on the drop change with the color of the drop? That might have sounded confusing. Example: you have say a blue backdrop and are using a bright pink gel, will you get a purple backdrop in the picture then? Or will it remain bright pink cause the gel light is stronger than the color of the backdrop? Just wondering if the backdrop color will change the color of the gel in the picture. Thanks.

Twila Davis Reed · #8 08-07-2006, 10:19 PM

It sort of depends on the intensity of the color of the drop along with how brightly you light it with the gel. That's what makes gels fun...they're SO adjustable! A very bright drop will probably show through quite a bit. Can make for some really interesting effects.

Like this one...I did this on a medium gray cloud drop and used a medium brown and a dark red gel to get the burgundy. I used a honeycomb grid on this and you can see the edges where it looks like the gray is showing through to vignette a bit. Love light falloff!

Second one is the same drop with just a red cap over a cheapie background slave light (pre-Alien Bees!) but it was held from above by a studio helper and the main softbox could spill onto it so that it was slightly more muted.

Third is the same drop yet again and with a dark green and baby blue gel layered (might have had a light yellow in there too, don't remember for sure), no honeycomb grid and I let the main light spill onto it bit.

Vance · #9 08-08-2006, 09:29 AM

I've used gels also. It is the easiest way to get variety out of your background. Here on the football pictures I applied a red gel to a painted brown background. The set up was easy. The light was a mobilight - 300 with barn doors and red gel insert that are sold for JTL.

http://www.silverlakephoto.com/JTL-M...-pr-16397.html

The last one is a fog machine against a plain black BG with the same light aimed into the fog. I also used one main light with a snoot and another colored gel.

fdpiech · #10 08-08-2006, 10:30 AM

Great posts everyone... Just Great!

My avitar, is using a blue gel... just shot in my dineing room...

And these two... Using blue and Red...

Silverlake · #11 08-08-2006, 12:58 PM

Nice Gel work everyone.

Yes, Kari, Parabolics are not only the reflector cones that concentrate and disperse your flash tube, but can also be bigger units used in place of a soft box or umbrella. The one I used for the samples was a small reflector like the ones that come with most professional strobes.

As Twila, Vance and Frank have demonstrated, the color and tone of your background will alter the looks of your gels. Lighter backgrounds will tend to give a more pastel look when gelled and darker backgrounds will tend to give more richly saturated colors. You can also achieve some unique effects by firing the gel through the background from the back side (if you have room in your studio to accomplish this).

Travis

fdpiech · #12 08-08-2006, 01:07 PM

Quote:

Originally Posted by Silverlake

You can also achieve some unique effects by firing the gel through the background from the back side (if you have room in your studio to accomplish this).

Hummm.... Note to self... must play with this...

nicleigh · #13 08-08-2006, 01:22 PM

Hmmm, this is very interesting! I think it would be very nice to be able to have many different looks from one backdrop. What would I need to hold the gels onto my bee?

fdpiech · #14 08-08-2006, 01:27 PM

Quote:

Originally Posted by nicleigh

Hmmm, this is very interesting! I think it would be very nice to be able to have many different looks from one backdrop. What would I need to hold the gels onto my bee?

I have the gel holder for my bees, but you can go as simple as some goffers tape.

Vance · #15 08-08-2006, 02:14 PM

Frank,

I've heard of and used gaffers tape. Is goffers tape what Bill Murray used to tie the ground hog to the steering wheel in "Ground Hog Day"?