Friday, January 18, 2013

How to: Gelling Large Light Sources


Do you shoot with soft boxes, beauty dishes and/or umbrellas?

If you shoot exclusively with small lights, you can just tape a couple of square inches of gel to your flash head, as with my permanently mounted warming gel seen above. No matter what the mod, the light is gelled before it gets there.

But if you sometimes shoot with big lights, things can get a little more complicated. Here are some ideas to help you gel the big mods as efficiently as possible.
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Basically, the idea is that you want complete coverage without using a ton of gel material. If I can gel a mod with a single 20x24" sheet of gel, I am much happier than if I have to buy several sheets of gel to do the job. Bearing that in mind, let's run through how to gel some of the more common big mods.


Beauty Dish

Beauty dishes, typically 22" in diameter, are great portrait mods for a number of reasons. They give beautiful light, and they stand up to wind outdoors. And happily, you can gel the whole front surface with a single 20x24" sheet of gel if you tweak the dimensions with some scissors and scotch tape.



You do this by cutting a two-inch strip off of a standard 20x24" sheet to make it 20x22". You have to get it pretty exact, too—you'll need every bit of gel on both dimensions. Then you tape the 2" strip to the side to make a 22x22" sheet with a couple of chopped up corners.

No worries, as that the corners will be waste after you trace and cut the gel to fit your dish. (But remember to save the scraps for your speedlights.)

Alternately, some people prefer to cut a smaller circle and put a Velcro® dot in the center. You can then stick it to another Velcro® dot on the shield that sits in front of your tube.

I like the full-sheet version here, as you can sometimes lose full coverage with a floppy gel if you go the other route. After all, it's just one sheet so it is not too expensive to do it right. Also, by using a full sheet you can work without the flash tube tube shield if you want more specular light

UPDATE, from commenter Andrei Popovici, below:

Here's an alternative way to gel your dish with less material.



Just cut a strip, tape it into a donut and slide it around your centerpost light blocker/reflector. (Thanks Andrei!)


Umbrellas

Pain in the butt to gel an umbrella, right? Wrong. It's dead simple if you use a cheap spill-kill reflector with a tiny hole in it to account for the shaft. Spill kills are cheap, and they also make an umbrella into a much better light source.



(Note: For clarity, this is shown without the umbrella shaft inserted.)

You can tape the corners back to ensure no ungelled light leakage on the light that is headed to the umbrella. But be careful to make sure there is some ventilation space between the gel and your modeling light. Even so, use the modeling light as sparingly as possible to prevent melting.

Of course you'll have to snip a tiny hole in your gel to account for the umbrella shaft. You can still use this small gel sheet over standard reflectors when needed by sticking a small piece of gaff over that hole to block raw white light spilling through it.

This method also holds true for anything that it umbrella-based, such as umbrella/diffuser mods like my go-to Photek Softlighters.


PLM

Gelling a Paul Buff PLM couldn't be simpler and takes very little gel material. If you are using it with an umbrella shaft mount, gel it as seen above.

If you are using the speed ring mount for perfect parabolic positioning of your light, you'll need even less material. Use the triangular "Death Star" area of the frame to wrap a small piece of gel thusly:



You'll easily get full, absolute coverage with a minimal amount of gel. Just remember to vent it a tad up top or down below at the back edge for heat dissipation.


Soft Boxes

To be honest, gelling issues are one reason I really am not a huge fan of soft boxes. With some boxes you can velcro a smallish piece of gel inside and get full coverage. But it is always clunky at best, and difficult not to get some white light leakage.

With small- to medium-sized boxes you can gel the front completely, which is something I did for many years when I used my 24x36" soft box literally to death in the 1990s. But to do so you'll need two sheets of 20x24" gel, which you tape together to make a single 40x24" sheet. Trim 4" off one side and you're set.

Not ideal, as it is not very efficient. But if that is your go-to key light, it's probably worth the effort and cash to have some full-front gels for it.

Just use sticky Velcro® tabs on the corners of the soft box and the gels and you are golden. Or fluorescent green. Or whatever. If you shoot a lot of head shots in tungsten or fluorescent environments, it's worth having a color correction set (CTOs, window green, etc.)

And you can also stack gels (for instance, green correction + key light warmth) by putting a set of Velcro® hooks on one side of the gels and loops on the others.

It's not an ideal solution, but if that is your go-to source that will be your best route.


Strip Boxes

Because of their size, which is generally small in terms of raw square inches, (i.e., 10x36", etc.) strips can be treated like small boxes. Which is to say you can gel the on the outside with a single 20x24" sheet of gel, which makes it pretty doable.

Take one 20x24" sheet and cut it down the middle to make two 20X12" strips. Tape those end-to-end to make a 40x12" strip and trim to fit your box. Mount to the front with Velcro® as described above. As always, when custom-fitting gels save the scraps for your speedlights—especially since they will usually be the colors you use most often.

Good news is, with strip boxes you are often going to be rim lighting someone anyway. Which usually lends itself to a fairly standard selection of color correction gels (CTO's, CTB's. etc.).

So it might make sense to keep a set of those colors (remember to do two of each if for rims). But for anything crazy, you'll likely be reverting to standard reflectors to make gelling easier/cheaper when using whack colors.



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33 Comments:

Blogger Josh McElwee said...

David,

Just wanted to make sure that I'm clear on gelling the PLM, you gel all three 'triangles' of the speedring, right? Gaff tape?

January 18, 2013 1:06 AM  
Blogger David Hobby said...

@Josh-

Yep, just wrap it around. You can make a template out of paper and then cut gels to fit if you want, too.

If I was doing it a lot (I'm not, really, as I mostly use the Softlighter) I'd velcro one arm and also each end of the cut gel. Then just wrap and stick as needed.

January 18, 2013 1:09 AM  
OpenID myamericanmyth said...

So that's how...great info!

Having a hard time visualizing the hooks and loops stacking though.

January 18, 2013 1:19 AM  
Blogger Gustav Lindh said...

Gelling softbox? Just gel the middle diffusion with some tape instead of the whole front.

January 18, 2013 1:27 AM  
Blogger weathershenker said...

When I finally had a list of reasons why studio lights would be a better choice over smaller strobes, I finally upgraded to Einsteins last summer. My first big problem was how to gel! I looked all over and didn't find solutions as nice as you've shown here. (I taped a full gel sheet over each beauty dish.) Love that velcro dot idea!

...and oh wow. I can finally gel an umbrella. (duh!)

- weathershenker

January 18, 2013 1:56 AM  
Blogger Andy Chubb said...

David,

insightful ideas as always. I'm just a 'gel-the-flashhead' guy myself, but reading this I was wondering whether the distance of the gel from the light source made a difference to the colour intensity coming off the gel?

For small flashes, you have got the gel pretty close to the flash tube (and no air in-between). When you stick a gel sheet on the front of a softbox then you will have perhaps 12" between them and a lot of (hot) air.

Any thoughts?

andyc

January 18, 2013 2:55 AM  
Blogger Felipe Curvello Anciaes said...

David,

Gelling only the light source (eg, the speedlight), before the modifier itself, isn't as good as gelling the modifier?
Tks!
Felipe

January 18, 2013 6:35 AM  
Blogger Bill Giles said...

When you use a gel on a 7 inch reflector with an umbrella or a softlighter, instead of cutting a hole for the shaft, take an Xacto knife and cut an X. The umbrella shaft will slide through the opening, but the flaps will fill the hole when the shaft is removed.

January 18, 2013 7:40 AM  
Blogger Jyrki K said...

For Elinchrom lights you can buy a set of deflectors that come in translucent, white, gold and silver. They are basically a short umbrella shaft with a round piece of plastic.

They can be used as they are or they could be gelled and put inside a softbox. This way a smaller piece of gel would be enough. A gold deflector is permanently put inside our big Rotalux that serves as fill light in the studio where I work.

January 18, 2013 7:44 AM  
Blogger D.Meds said...

So fitting it's the right time for this post as I started studying the controls and extending the exercises by what I knew and what I learnt with Strobist; 'coz I devoted my time to know my first softlight mod 'the umbrella' and wondered about how to gel it with my tests I kept the old habit of gelling the small head of the hotshoe flash an got the color I wanted, for me to confirm this fact at the beginning of the post make it a lot easier to tweak my thought for the big mods as I used to think it's all I need to gel a soft box is to gel the small head. thank you , but my wonder is 'if using big mods with small heads 'hotshoe' is that sufficient to just gel the small head because what I got is to gel a big mod you need to gel its front end a softbox as example. thank you a lot so helping.

January 18, 2013 8:28 AM  
Blogger David Hobby said...

@Gustav-

That works, if you are okay with the white light leaks you'll get around the edges of the baffle. I.e., not good for color balancing, getting a saturated color, etc.

January 18, 2013 9:58 AM  
Blogger David Hobby said...

@Andy, D.Meds and Filipe-

If you are using a speedlight, definitely gel the face of the light. No difference in the quality, and much much easier.

Only caveat is to leave a space and some top ventilation—especially if using a gel that absorbs a lot of light (and thus, heat). Or you'll get a permanently gelled flash.


@Bill-

That's a good idea.

January 18, 2013 10:01 AM  
Blogger D.Meds said...

@ David

I've experienced such a caveat I was on the brink of getting my permanent Blue geld flash.

Wow life is easy for speedlighters, a gel in front.

Thank you a bunch stamped in my head and solved a lot of wonder :)

January 18, 2013 10:31 AM  
Blogger hotshoeless said...

Thanks for the article, David. I've been thinking of getting an Einstein and wondering how to best use gels with it.

Paul C Buff has an accessory called the lightmod (http://paulcbuff.com/litemod.php) that is designed to hold gels, amongst other things. I haven't used it -- I'm guessing that a hole could be drilled through for an umbrella or you could fire it into some ripstop nylon in a frame, like the setups Dean Collins used to use. Has anyone here used this product or something similar from other lighting manufacturers?

Joe

January 18, 2013 10:57 AM  
Blogger Dana Neibert said...

We usually just gel the flash head. Way faster and just as efficient. Do you find that gelling the entire modifier gets different results?

January 18, 2013 11:23 AM  
Blogger Christopher J said...

I can't imagine how gelling the whole face of a modifier would not result in much more color saturation than gelling right at the source. The more light that travels through a filter, the less that light will be affected by the filter, right? If you gel at the source, you have a great deal of light traveling through a small bit of filter. If the gel is at the face of the modifier, you have the same density of filter but much less light per amount of surface area of gel and thus more effect of that gel. Is my logic off here?

Also, what do you think about using the bracket for the PLM inside of a softbox?

January 18, 2013 4:05 PM  
Blogger Antares said...

@Christopher-
The sheer volume of light has no effect on the efficiency of a filter.
However, how one exposes for the light can change the saturation in the image. Whether or not us gel the source or the modifier, the amount of light reaching the subject will stay the same.

(100/4)/2=(100/2)/4

January 19, 2013 9:36 AM  
Blogger Fenix Fotography said...

I find that the dome heads from my Gary Fong / Lambecy Diffusers fit the inside of my beauty dish PERFECTLY (not sure of other brands)--I have orange, yellow, green, and cyan.

If you pull the modeling bulb (I don't use them), they also mount to the front of my Alien Bees heads pretty well. You could gaff the small gap at the bottom if you're getting spill, but I haven't noticed it being a problem.


Here are some for $8: http://www.buy.com/prod/lambency-flash-diffuser-for-canon-580ex-ii-580ex-550ex/228202112.html?listingId=199263292

January 19, 2013 12:11 PM  
Blogger Christopher J said...

Thanks, Antares. Definitely counterintuitive, but I guess that's light for you, eh?

And as soon as I posted my last comment I realized you of course couldn't use a PLM bracket inside a softbox because the softbox's speedring would be occupying the mount.

January 19, 2013 4:47 PM  
Blogger Wink of an eye Digital said...

Great little ideas I'll add thatthe use of theater gels would eliminate potential fire hazard as they are flame proof on frenel and hot lights

Wink

January 19, 2013 9:58 PM  
Blogger Scott Gant said...

Hmmm, you see that dome covering the light and modeling light on the Einstein? That can be removed, yes?

While I know Buff Lighting doesn't offer this, but what is stopping someone from putting together a Kickstarter project to make domes for the Einstein that have the colored tint baked right into the dome itself? Instead of just having it white, you can make a variety of CTO's and tungsten and florescent color temps.

Probably get sued by PCB, but hey, it's just a thought, and would make life so much easier for those of us that want to alter our big lights without a hassle.

January 19, 2013 10:50 PM  
Blogger Unknown said...

David, might you ever want to not fully cover the light with a gel to get that mixed colour?

You have talked a few times recently about using not pure white light to appear more realistic.

What would it look like if your mod was half gelled and half white light? Creating a close to white but not fully effect?

January 19, 2013 11:28 PM  
Blogger dave moser said...

David -- with all due respect -- gelling the source inside the softbox is the way to go, instead of gelling the whole front of the box... same as gelling the head in a softlighter umbrella.

NO???

January 20, 2013 7:58 PM  
Blogger Andrew Wisler said...

@Scott Grant -- I was thinking the same thing. For that matter, PCB himself seems the perfect person to do this -- probably for a good price, too. Does anyone here have his ear, @David Hobby? Is there any technical reason this wouldn't work?

January 20, 2013 10:56 PM  
Blogger Kevin said...

David, for gelling softboxes, my solution is linked below. You have to be ok with lighting by meter or numbers, as you'll have to take the modeling lamp out (or not use it, since there'll be too much heat).

http://imgur.com/a/paifk

@ChristopherJ, the filters are rated by how much of each wavelength they block, so a 1-stop cyan filter will stop half of all the red light going through it. It is definitely counter-intuitive, and i'm too tired to think of a good analogy.

re: PLM gels, here's a template I made when I was cutting up sheets to make my own Rosco Calcolor set. I used 1/4 of a rosco gel sheet, so a 10x12" sheet, to provide one PLM-ready cone and 4 speedlight strips.
http://i.imgur.com/ChZTvRy.png

January 21, 2013 1:19 AM  
Blogger James said...

If you are going to cut a x for the umbrella shaft as sugested in a post above I would sugest putting clear tape around the hole to keep the x from expanding.

January 21, 2013 9:09 AM  
Blogger Nathan B said...

A photographer I know uses gels that would normally be used for disco lights. As disco lights are hot lights these gels are designed not to melt with heat. I don't know his source or how much more expensive they are vs normal gels for flash lights but I thought it worth mentioning as it may be useful to some. I do know he has a lot of different colors. I'm not sure if they have CTO 1/4, 1/2 and full colors though.

January 21, 2013 10:19 PM  
Blogger Chris Aldridge said...

This really surprises me with strobes, especially the larger monos. There are no provisions for a gel holder. Something that I'm very used to, and a given, with stage lights. Light is light, which means it all needs to be colored at some point!

January 25, 2013 12:46 PM  
OpenID openid said...

FIRST RULE OF PHOTOGRAPHY:
Don't overlook the possibility that the easiest solution is the best. (6' Elinchrom Octabanks can be gelled with a thin strip of gel around the flashtube)

SECOND RULE OF PHOTOGRAPHY:
There are no more rules...

February 12, 2013 11:16 PM  
Blogger filer said...

Someone upthread mentioned gaffer/duct tape. DO NOT USE. Use masking tape. The glue on Gaff tape can melt all over your equipment.

February 14, 2013 11:34 PM  
Blogger Andrei Popovici said...

Hi David,

I've been using a simpler solution for using gels with beauty dishes, especially from Paul C. Buff.

I just cut a strip of gel and wrap it around the light shield in the center, taping it around one of the screw posts holding up said light shield. It gives perfect coverage and it's far enough from the bulb for the heat to dissipate.

Cheers,
Andrei

March 21, 2013 5:30 AM  
Blogger Jon-Mark said...

Hi David, I'd love to hear your thoughts on this...

You know the little black plastic protective cover that comes with Alienbees ( and I assume Einstein ) lights? Why hasn't some company started manufacturing hard gels in this shape for these lights? They're still usable with things like umbrellas, softboxes, and beauty dishes, and would provide a fast, clean and easy way of gelling your studio lights. When I need to gel I always just end up using my speedlights because it's too much hassle with my studio strobes.

Have you ever heard of something like this?

If not, perhaps it's an idea you could pass on to your friends at MPEX or Rosco?

Love to hear your thoughts, feel free to message me directly at info@jonmarkphoto.com if you like

Cheers buddy
JM

July 15, 2013 4:55 PM  
Blogger David Hobby said...

@Jon-Mark-

Cool idea in theory, but I think hard gels would be 'spensive to manufacture -- convenient tho they may be for e640 owners... (And, brand specific.)

July 15, 2013 7:58 PM  

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