Jay's Light of The Day : Tip #2 (Balancing light temperature)

[jayhan]

Ok, I've mentioned about light quality in my previous posting... about how the size of the apparent light source could contribute to the harshness (or softness for that matters :P) of the light, and how this relates between the subject size too.

This second tip would be on how one could control light temperature, and how to balance it against the ambience light source.

Lets put it that we have 2 end of light temperature. Blue being cold, and of course red being warm (or hot?). Anyway, we shoot in various ambience that have varying light temperature. For an example, morning sun tends to be colder; while sunset will give a warm cast. Tungsten filled room will give orangy light; and fluorescent will give a rather greenish hue. All these lighting temperature will eventually convey to our camera's WB charts.

Now, the flash we are using, is what I personally consider as the "white light". Having such white light from a flash source (may it be harsh or soft - it doesnt matter) on your subject, while the ambience is of another color would make the photo seem a little out of place. This is because our camera's WB system just cant accomodate both WB spectrum the photo is being exposed to. For an example, which I'm sure many of us has done this before - is a portrait shot taken in tungsten lit room. The ambience will turn orangy while the subject is white. This is absolutely not cool. Acceptable photo it may be - but not the best, which I'm sure many of us would wanna achieve.

How do we rectify such problem? Simple. Colored gels are here to save the day.

We use colored gels to convert the whitish flash light source into some other color of our choice. The spectrum of colored gels is almost infinite (it goes as deep as your pocket), so it can be used for creative reasons as well.

Here's an example of how to balance up a portrait shot which would have been taken under tungsten condition.

1. Use an orange gel (technicall also known as CTO @ Color Temperature Orange) to convert the flash light
2. From this, we would get a similar light temperature, as that of the tungsten from the ambience.
3. Set the WB to TUNGSTEN (or custom WB also can)
4. Take the shot.

The result should be a well balanced portrait with no color variation from the light source.

Hope this helps.

[noordin]

Thanks for the tip. We tend to forget this sometimes if we shoot RAW but for film it's absolutely essential.

[ZhenMing]

WOW.. another good sharing!!!

Now i understand more on the color gel...

[sinister]

Thanks for the tip. We tend to forget this sometimes if we shoot RAW but for film it's absolutely essential.

not necessarily, even if ur using RAW, u might need d gel, as in case u want to mix match using both tungsten and a few flash so dat u can get balance lighting

[ShaolinTiger]

Yah even with RAW you can't fix this, no PP can fix this problem.

As the white balance will give the subject the correct colour temperature but the background will be green or orange depending on the ambient light.

That's why for example SB-800 comes with CTO and Tungsten gels for balancing ambient light with flash.

[ZhenMing]

talking about the sb800 color gel.. it should be 2 pcs or only 1 har?

[ShaolinTiger]

talking about the sb800 color gel.. it should be 2 pcs or only 1 har?

2 pieces, 1 CTO & 1 Green.

[iamyuanwu]

But hor...
Where to buy [CTO & flourescent] gels?

[ShaolinTiger]

There's another article you can read here if you want to understand more:

Lighting 101: Using Gels to Correct Light (http://strobist.blogspot.com/2006/03/lighting-101-using-gels-to-correct.html)

[ZhenMing]

Great article.. ST... Bookmarked... thanks again...

[jayhan]

Ahh I bet mr. strobist can explained more in details as compared to my pee-wee attempt. :)

[hotdrive]

thanks for sharing.... all is noted.

:)

[kiankheong]

A great read. Now, if only my SB-600 can accommodate such coloured gels. :(

[karheng]

A great read. Now, if only my SB-600 can accommodate such coloured gels. :(

In retrospect, you could also convert some colours on the DFD(flip it) or the Lightsphere with the orange cap...

similar stuff as coloured gels....

[Lights]

Ok, I've mentioned about light quality in my previous posting... about how the size of the apparent light source could contribute to the harshness (or softness for that matters :P) of the light, and how this relates between the subject size too.

This second tip would be on how one could control light temperature, and how to balance it against the ambience light source.

Lets put it that we have 2 end of light temperature. Blue being cold, and of course red being warm (or hot?). Anyway, we shoot in various ambience that have varying light temperature. For an example, morning sun tends to be colder; while sunset will give a warm cast. Tungsten filled room will give orangy light; and fluorescent will give a rather greenish hue. All these lighting temperature will eventually convey to our camera's WB charts.

Now, the flash we are using, is what I personally consider as the "white light". Having such white light from a flash source (may it be harsh or soft - it doesnt matter) on your subject, while the ambience is of another color would make the photo seem a little out of place. This is because our camera's WB system just cant accomodate both WB spectrum the photo is being exposed to. For an example, which I'm sure many of us has done this before - is a portrait shot taken in tungsten lit room. The ambience will turn orangy while the subject is white. This is absolutely not cool. Acceptable photo it may be - but not the best, which I'm sure many of us would wanna achieve.

How do we rectify such problem? Simple. Colored gels are here to save the day.

We use colored gels to convert the whitish flash light source into some other color of our choice. The spectrum of colored gels is almost infinite (it goes as deep as your pocket), so it can be used for creative reasons as well.

Here's an example of how to balance up a portrait shot which would have been taken under tungsten condition.

1. Use an orange gel (technicall also known as CTO @ Color Temperature Orange) to convert the flash light
2. From this, we would get a similar light temperature, as that of the tungsten from the ambience.
3. Set the WB to TUNGSTEN (or custom WB also can)
4. Take the shot.

The result should be a well balanced portrait with no color variation from the light source.

Hope this helps.

Jay; i tested this method using the orange colored cto flash in a restaurant lit with tungsten lighting and with the camera set to tungsten WB, but no doubt the picture turned out all in similar colour but I wanted a normal picture without orangy cast. Is there any other thing that I missed out?

[simonliu]

Jay; i tested this method using the orange colored cto flash in a restaurant lit with tungsten lighting and with the camera set to tungsten WB, but no doubt the picture turned out all in similar colour but I wanted a normal picture without orangy cast. Is there any other thing that I missed out?

Well, what u can easily do is take a few test shots with different WB settings n see which one suites your flavour. The idea of using the color Gel is so that your subjects blend in the with background when u use flash. The other option u can try is manual WB and select the right K value.

......on the other hand....swithc to Nikon!!!! whahahahaha.

[jayhan]

actually switching to nikon may not necessary help in this case :P *seriously*

in order to rectify, or balancing the color temperature of the foreground and the background ambient, you will need to embrace 1 thing, and that is how contrasting is the color range. you see, that is the reason why they have 1/2 CTO, 1/4 CTO, 3/4 CTO and also (full) 1/1 CTO. it gives you that bracketing in different range of orangy cast.

hope this helps.

[astroboy]

In theory it should work but in practice...well... the results will be inconsistent.

I have shot a printing press factory all lit up with fluorescent w/out gels and it turned out quite well after PS.

Likewise i have shot interiors all lit up with incandescent bulbs w/out gels. All i need to do is pick a black and white point to restore the correct WB.

Shoot RAW. Convert to a few jpeg versions and apply WB accordingly. Stack up the different versions on one file. Use digital blending, layer mask and a soft brush to "paint" in the correct colours u want. That's the digital way.

There are many paths to enlightenment...

:rasta:

[siew]

Switching to other camera brands will not balance multiple light source with different temperatures.

In an event environment where the intensity of the ambient light varies from one place to another, it is not easy getting consistent colour balance when used in combination with flash + colour gels (to match the ambient light). You'll need to do test shots to get the balance you need by varying the intensity of the colour gels as Jay mentioned. You could achieve uniform colour temperature (for a set of pictures) by using fixed flash output (and distance from the subject) and setting a fixed colour temperature manually.

Having said that, some newer cams do have better AWB compared to others. Hence you may not need to set the colour temperature manually.

I hope this helps and always shoot RAW in order to maximise your cam's capability:D.

[jayhan]

In theory it should work but in practice...well... the results will be inconsistent.

I have shot a printing press factory all lit up with fluorescent w/out gels and it turned out quite well after PS.

Likewise i have shot interiors all lit up with incandescent bulbs w/out gels. All i need to do is pick a black and white point to restore the correct WB.

Shoot RAW. Convert to a few jpeg versions and apply WB accordingly. Stack up the different versions on one file. Use digital blending, layer mask and a soft brush to "paint" in the correct colours u want. That's the digital way.

There are many paths to enlightenment...

:rasta:

very true. the digital way can solve this in many steps.
put a model into the photo and light him/her up with flash in the said condition, and you will need yet extra steps to layer adjustment him/her on top of the skin quality adjustments. so, depends lo... so photoshop super skill can do it within a few steps nia. hehehe

[qqmeng]

In theory it should work but in practice...well... the results will be inconsistent.

I have shot a printing press factory all lit up with fluorescent w/out gels and it turned out quite well after PS.

Likewise i have shot interiors all lit up with incandescent bulbs w/out gels. All i need to do is pick a black and white point to restore the correct WB.

Shoot RAW. Convert to a few jpeg versions and apply WB accordingly. Stack up the different versions on one file. Use digital blending, layer mask and a soft brush to "paint" in the correct colours u want. That's the digital way.

There are many paths to enlightenment...

:rasta:

the master has spoken :)

[Lights]

TQVM guys great understanding n need to practice more

[astroboy]

i m not worthy to be called "master"...
:redface:


the master has spoken :)

[donnyyeo]

But hor...
Where to buy [CTO & flourescent] gels?
If your flash unit is small, you can buy Rosco Roscolux Swatchbook.
Btw, I am selling them at the Buy/Sell section.

ST, sorry for the advert.