Color correcting your flash

blackhawk wrote in post #9473821
Did you shot them as RAWs?

Pure RAW shooter, buddy ('cept when shooting birthdays of a friend's daughter/son, in which case, JPEG.).

Canonboi wrote in post #9473919
Pure RAW shooter, buddy ('cept when shooting birthdays of a friend's daughter/son, in which case, JPEG.).

Good!

egordon99 wrote in post #9473850
Did you read my post above? https://photography-on-the.net …php?p=9473099&p​ostcount=3

Maybe other shots have a lot of ambient light mixed in, but in the shot you posted I would think you'd want the flash to provide ALL the illumination. And thus no need for gels.

Yes I did, brother. But only now did I get your point. So you mean to say, if you like to kill the ambient, no need for gels? = gels are used to mix ambient and flash? Got it.

But then, that's what I was trying to do then. My settings on this particular shot: 1/125th, ISO 800, 5.6.

I'm always trying to mix in ambient and flash, otherwise I know just how to kill that ugly green fluorescent.

PaulB wrote in post #9473874
The rule for colour compensation is to use the complimentary colour to that which is causing the cast.
Fluorescents tend to give a green cast as you say but to counter that the complimentary colour needed is magenta.
To counter the warm yellow cast of a tungsten bulb the filter would be blue.

Don't know where that guy in your URL got his ideas from but in this instance he is plain wrong!

What's wrong with AWB on the camera, usually does a good job? And then use Photoshop to correct any small imbalance.

Damn dude! I was shooting the whole time applying that b@$****'s advice!

What's wrong with AWB was it almost always give me a little too warm cast, especially in tungsten environment.

Do you have any suggestions as to how to correct these photos? Most of them are shot under fluorescent lighting. How do I remove the green cast in LR/PS? Please help. These photos are so important to me since they are family pictures.

Well since you shot in RAW, go to LR and try to find a good color temp...then apply that same # to all of the same pictures taken in the same environment

Canonboi wrote in post #9473939
Yes I did, brother. But only now did I get your point. So you mean to say, if you like to kill the ambient, no need for gels? = gels are used to mix ambient and flash? Got it.

But then, that's what I was trying to do then. My settings on this particular shot: 1/125th, ISO 800, 5.6.

I'm always trying to mix in ambient and flash, otherwise I know just how to kill that ugly green fluorescent.

But if you did a bounce on the ceiling, that room seems small enough that you wouldn't NEED to let ANY ambient light in the shot. Not sure how bright it was, but I'd think with 1/125, ISO800, f/5.6 you probably weren't letting much of the fluorescent light in.

You generally want to mix ambient light in when your flash can't illuminate the entire scene. For example, in a typical reception hall (for a wedding), a bounced flash will light up the subjects that are right in front of you, but the background will be quite far away, so if you do the standard 1/250s the background will be pitch black and the flash light won't reach that far and 1/250s (+whatever ISO, f-stop you are using). This is like my example where I have you take two pictures, same camera settings, and the one with flash is completely black. So you slow down the shutter until some ambient light "registers". The problem is now that the ambient light is "lit" by lights that are a different color temperature than your strobes. So if you set the white balance for the subject (lit by flash), the white balance of the background (lit by flourescent/tungsten) will be off. THAT is when you need to gel your flash.

Canonboi wrote in post #9473957
Damn dude! I was shooting the whole time applying that b@$****'s advice!

What's wrong with AWB was it almost always give me a little too warm cast, especially in tungsten environment.

Do you have any suggestions as to how to correct these photos? Most of them are shot under fluorescent lighting. How do I remove the green cast in LR/PS? Please help. These photos are so important to me since they are family pictures.

Try one click color balance in DPP, changing picture styles might also help... sometimes you can get better results editing RAWs in DPP.

egordon99 wrote in post #9473988
But if you did a bounce on the ceiling, that room seems small enough that you wouldn't NEED to let ANY ambient light in the shot. Not sure how bright it was, but I'd think with 1/125, ISO800, f/5.6 you probably weren't letting much of the fluorescent light in.

You generally want to mix ambient light in when your flash can't illuminate the entire scene. For example, in a typical reception hall (for a wedding), a bounced flash will light up the subjects that are right in front of you, but the background will be quite far away, so if you do the standard 1/250s the background will be pitch black and the flash light won't reach that far and 1/250s (+whatever ISO, f-stop you are using). This is like my example where I have you take two pictures, same camera settings, and the one with flash is completely black. So you slow down the shutter until some ambient light "registers". The problem is now that the ambient light is "lit" by lights that are a different color temperature than your strobes. So if you set the white balance for the subject (lit by flash), the white balance of the background (lit by flourescent/tungsten) will be off. THAT is when you need to gel your flash.

Thanks for explaining these things to me. Especially the how-to of knowing if you are letting enough ambient to the shot. Thanks so much.

I did bounced the flash on ALL of my shots regardless of room size. I should've known that. Now I'll spend my time "color correcting" my photos in post. Sad times.

blackhawk wrote in post #9474070
Try one click color balance in DPP, changing picture styles might also help... sometimes you can get better results editing RAWs in DPP.

Okay, man. I might use DPP now.

The point of using the same color gel as the source (green filter for fluorescent ambient lighting) is to make the lighting sources match - then you use the complimentary color in post processing to get the white balance.

If you use a magenta filter on the flash when shooting in fluorescent, you have green light from the flourescent, magenta light from the flash - so you are not getting the same lighting on the subject. In places where both light sources (green and magenta) hit the subject, it can cancel out, but in places where one or the other hit the subject you have opposite color casts (not easy to correct later in PP).

Canonboi wrote in post #9474086
Okay, man. I might use DPP now.

DPP has gotten a lot better in the last year. Make sure to set it to your corrected monitor color profile first though.
Preferences>Tools> Color Management

Download any updated versions too, last one was Sept 09, I think.

^^Will do that and report my progress. Thanks a bunch.

Acropora wrote in post #9474112
The point of using the same color gel as the source (green filter for fluorescent ambient lighting) is to make the lighting sources match - then you use the complimentary color in post processing to get the white balance.

If you use a magenta filter on the flash when shooting in fluorescent, you have green light from the flourescent, magenta light from the flash - so you are not getting the same lighting on the subject. In places where both light sources (green and magenta) hit the subject, it can cancel out, but in places where one or the other hit the subject you have opposite color casts (not easy to correct later in PP).

What do you exactly mean by "use the complimentary color in post processing to get the white balance"? And are you saying that using a green gel (tough plusgreen to be exact) is okay? I need a whole crash course in color balance.

PaulB wrote in post #9473874
The rule for colour compensation is to use the complimentary colour to that which is causing the cast.
Fluorescents tend to give a green cast as you say but to counter that the complimentary colour needed is magenta.
To counter the warm yellow cast of a tungsten bulb the filter would be blue.

Don't know where that guy in your URL got his ideas from but in this instance he is plain wrong!

What's wrong with AWB on the camera, usually does a good job? And then use Photoshop to correct any small imbalance.

You could do this...
1. Gel fluorescents with 30M, then shoot daylight balance

or you could do this...
2. Gel flash with Plusgreen filter, then shoot Fluorescent balance

or you could do this...
3. Shoot with no filters, and try as best as you can to deal with Mixed lighting in postprocessing.

Canon AWB is pretty suboptimal in its results!

Wilt wrote in post #9474416
You could do this...
1. Gel fluorescents with 30M, then shoot daylight balance

or you could do this...
2. Gel flash with Plusgreen filter, then shoot Fluorescent balance

or you could do this...
3. Shoot with no filters, and try as best as you can to deal with Mixed lighting in postprocessing.

Canon AWB is pretty suboptimal in its results!

Sorry I should have expanded on the filter use a bit, I assumed that (I know, never assume!) the correction filter would be on the lens with the flash gelled up to match the ambient lighting.
I still don't understand why Canonboi needs to get so complicated with things - AWB with postprocessing seems the easiest way to go for this type of family photo. I find that AWB does a fair job, (you can also do a custon WB off a gray/white card and see if that's better), but perhaps I'm not using the same cameras.
As the files are RAW's I see even less of a problem with pp'ing them, so why introduce complications at the shooting stage?