Use flash gels or white balance in post ?

London Rob · 01-04-2013, 05:15 AM

So I'm moving into speedlight photography and have a couple of indoor hotel room/bar gigs coming up. My question is do I really need to gel my flash heads to match the lighting in the space or do what I would normally do ? Namely take an 18% grey card shot, set white balance, then tweak the WB of the RAW in post if it needed it.

I'm all for getting the shot right first time but I'm way off understanding what gel to use for what could be a mix of bulbs and light sources so am I missing something here, can I not just fix in post as normal ?

VisualDarkness · 01-04-2013, 05:49 AM

If you use a flash with a different color temperature than the ambient lighting you get two different temperatures in the shot. If you adjust WB for the flash the ambient light gets thrown off and vica versa. You can try this by putting two different lights beside each other in a photo and try to adjust for one or both, they will never be the same. Though often you can use the flash neutral without any huge effect.

**JimJohnson** · 01-04-2013, 05:51 AM

In my opinion, it depends on how much ambient light will appear in your images and its impact on your subject.

You can white balance in post processing, but only for one lighting type*. You indicate a mix of bulbs and light sources. Either by elimination or filtration, you must control your scene to only one lighting color temp. So if ambient light will have to be white balanced as well as the flash output, then yes, match the flash output to your ambient lighting via gels.

(* unless you are willing to take the time to slice your image into multiple layers in Photoshop based on color temp, balance each layer, and reassemble - sounds like a whole lot of needless work to me)

**davidreilly3207** · 01-04-2013, 05:52 AM - **1 Like**

Strobist: Lighting 101: Using Gels to Correct Light

Na Horuk · 01-04-2013, 08:08 AM - **1 Like**

Switch wb to CTE and call the series "light is orange, deal with it"

Zafar Iqbal · 01-04-2013, 02:32 PM

If you are going to more or less mix the flash with ambient then go with gels. You'll love it.

mikeSF · 01-04-2013, 04:26 PM

i recommend using gelled flash but I have had decent results just shooting with naked flash and then double processing the same image for two (or more) color temps and combining.

mikeSF · 01-04-2013, 04:36 PM - **1 Like**

here is an example of double processing.

I used a naked(ungelled) flash in this hotel restaurant...the subjects look fine but the tungsten lit background is an orange nightmare...

I made a copy of that shot and set the white balance to TUNGSTEN, now the background looks right but the subjects are too bloo!

Layering one over the other and using a layer mask to reveal just the correct parts of each, i get this:

Of course, if I had started with a gel on my flash that matched the majority of the background light, i wouldn't have to do anything.

London Rob · 01-05-2013, 07:53 AM

Wow ! Those photos tell me everything I need to know, thank you ! looks like I need to gel up.......

**JimJohnson** · 01-05-2013, 08:19 AM

Originally posted by mikeSF

here is an example of double processing.

I used a naked(ungelled) flash in this hotel restaurant...the subjects look fine but the tungsten lit background is an orange nightmare...

I made a copy of that shot and set the white balance to TUNGSTEN, now the background looks right but the subjects are too bloo!

Layering one over the other and using a layer mask to reveal just the correct parts of each, i get this:

Yep. You did the part I put in parenthesis in my post. You did a nice job of it too, not to mention demonstrating visually what most of of use were trying to describe in writen format. Out of curiosity, any idea how much time you spent in post processing for just this one photograph? (and for the record, I am assuming you are much faster at this type of Photoshop manipulation than I would be)

mikeSF · 01-05-2013, 12:38 PM

Originally posted by JimJohnson

Yep. You did the part I put in parenthesis in my post. You did a nice job of it too, not to mention demonstrating visually what most of of use were trying to describe in writen format. Out of curiosity, any idea how much time you spent in post processing for just this one photograph? (and for the record, I am assuming you are much faster at this type of Photoshop manipulation than I would be)

i've gotten fast at making masks. That said, one can whip up something sloppy in a couple minutes or something perfect in half an hour...and all points in between. With these vacation snapshots, i put minimal time into the mask. I copied one image onto the other. next i used the quick selection tool (or magic wand) to choose the people...checked it with the quick mask mode to clean up any missed spots. Then while the selection is still active, I choose the "create new mask" and it automatically makes the mask out of the selection. Finally, i use a soft brush on the mask to clean up any stray outlines, hair/fur, etc...really, this could take 5 minutes.
i hope that helped.
Now for my landscape pics that i really care about, i could spend an hour double and triple processing for several white balance settings and blending in each corrected light source, etc...

01-04-2013, 05:15 AM	#1
London Rob Forum Member Join Date: Apr 2011 Photos: Albums Posts: 92	Use flash gels or white balance in post ? So I'm moving into speedlight photography and have a couple of indoor hotel room/bar gigs coming up. My question is do I really need to gel my flash heads to match the lighting in the space or do what I would normally do ? Namely take an 18% grey card shot, set white balance, then tweak the WB of the RAW in post if it needed it. I'm all for getting the shot right first time but I'm way off understanding what gel to use for what could be a mix of bulbs and light sources so am I missing something here, can I not just fix in post as normal ?

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01-04-2013, 05:49 AM	#2
VisualDarkness Veteran Member Join Date: Nov 2011 Location: Uppsala, Sweden Photos: Gallery Posts: 4,439	If you use a flash with a different color temperature than the ambient lighting you get two different temperatures in the shot. If you adjust WB for the flash the ambient light gets thrown off and vica versa. You can try this by putting two different lights beside each other in a photo and try to adjust for one or both, they will never be the same. Though often you can use the flash neutral without any huge effect.

01-04-2013, 05:51 AM	#3
JimJohnson Loyal Site Supporter Join Date: Jan 2012 Location: Summer:Lake Superior - Michigan Winter:Texas Hill Country Photos: Gallery Posts: 2,774	In my opinion, it depends on how much ambient light will appear in your images and its impact on your subject. You can white balance in post processing, but only for one lighting type. You indicate a mix of bulbs and light sources. Either by elimination or filtration, you must control your scene to only one lighting color temp. So if ambient light will have to be white balanced as well as the flash output, then yes, match the flash output to your ambient lighting via gels. ( unless you are willing to take the time to slice your image into multiple layers in Photoshop based on color temp, balance each layer, and reassemble - sounds like a whole lot of needless work to me)

01-04-2013, 05:52 AM - 1 Like	#4
davidreilly3207 Loyal Site Supporter Join Date: Sep 2009 Location: South Jersey Photos: Gallery \| Albums Posts: 720	Strobist: Lighting 101: Using Gels to Correct Light

01-04-2013, 08:08 AM - 1 Like	#5
Na Horuk Veteran Member Join Date: Feb 2012 Location: Slovenia, probably Photos: Gallery \| Albums Posts: 11,186	Switch wb to CTE and call the series "light is orange, deal with it"

01-04-2013, 02:32 PM	#6
Zafar Iqbal Veteran Member Join Date: Oct 2010 Photos: Gallery Posts: 1,229	If you are going to more or less mix the flash with ambient then go with gels. You'll love it.

01-04-2013, 04:26 PM	#7
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,622	i recommend using gelled flash but I have had decent results just shooting with naked flash and then double processing the same image for two (or more) color temps and combining.

01-04-2013, 04:36 PM - 1 Like	#8
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,622	here is an example of double processing. I used a naked(ungelled) flash in this hotel restaurant...the subjects look fine but the tungsten lit background is an orange nightmare... I made a copy of that shot and set the white balance to TUNGSTEN, now the background looks right but the subjects are too bloo! Layering one over the other and using a layer mask to reveal just the correct parts of each, i get this: Of course, if I had started with a gel on my flash that matched the majority of the background light, i wouldn't have to do anything.

01-05-2013, 07:53 AM	#9
London Rob Forum Member Join Date: Apr 2011 Photos: Albums Posts: 92 Original Poster	Wow ! Those photos tell me everything I need to know, thank you ! looks like I need to gel up.......

01-05-2013, 08:19 AM	#10
JimJohnson Loyal Site Supporter Join Date: Jan 2012 Location: Summer:Lake Superior - Michigan Winter:Texas Hill Country Photos: Gallery Posts: 2,774	Originally posted by mikeSF here is an example of double processing. I used a naked(ungelled) flash in this hotel restaurant...the subjects look fine but the tungsten lit background is an orange nightmare... I made a copy of that shot and set the white balance to TUNGSTEN, now the background looks right but the subjects are too bloo! Layering one over the other and using a layer mask to reveal just the correct parts of each, i get this: Yep. You did the part I put in parenthesis in my post. You did a nice job of it too, not to mention demonstrating visually what most of of use were trying to describe in writen format. Out of curiosity, any idea how much time you spent in post processing for just this one photograph? (and for the record, I am assuming you are much faster at this type of Photoshop manipulation than I would be)

01-05-2013, 12:38 PM	#11
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,622	Originally posted by JimJohnson Yep. You did the part I put in parenthesis in my post. You did a nice job of it too, not to mention demonstrating visually what most of of use were trying to describe in writen format. Out of curiosity, any idea how much time you spent in post processing for just this one photograph? (and for the record, I am assuming you are much faster at this type of Photoshop manipulation than I would be) i've gotten fast at making masks. That said, one can whip up something sloppy in a couple minutes or something perfect in half an hour...and all points in between. With these vacation snapshots, i put minimal time into the mask. I copied one image onto the other. next i used the quick selection tool (or magic wand) to choose the people...checked it with the quick mask mode to clean up any missed spots. Then while the selection is still active, I choose the "create new mask" and it automatically makes the mask out of the selection. Finally, i use a soft brush on the mask to clean up any stray outlines, hair/fur, etc...really, this could take 5 minutes. i hope that helped. Now for my landscape pics that i really care about, i could spend an hour double and triple processing for several white balance settings and blending in each corrected light source, etc...