Sunday, 24 February 2013

Fire Painting: Capturing the Firewall





Before you read this blog please ensure you have read the previous blog relating to fire painting a firewall, "Light Painting with fire, a fire wall" this blog covers very important safety advise which must not be overlooked!

Disclaimer:  I provide this guide for reference only,  before you come to any conclusions I strongly advise you read other sources of information regarding fire and fuels, this will ensure you have a good grasp on the larger picture.   As with all information on the Internet you should never rely on just one source, use multiple and fully understand every aspect before you commit.


Introduction
I have received a lot of questions on how best to shoot a firewall, a lot of people have been suffering from over exposure.  So I've decided to write a blog to try and help answer some of those questions, if you have any further questions please comment on this blog or head over to my facebook page.

When fire painting a firewall or firewave the main issue you will encounter is over exposure, this can be affected by several factors, which will be covered in this blog, they include.


  • Wind
  • Ambient temperatures
  • Speed at which you walk
  • Rope or strap thickness
  • Distance from camera
  • Camera settings.

To better understand each element let's break them down into bite sized portions.



Wind

Wind doesn't help when fire painting,  if there is wind it will cause the flames to flicker, it will reduce the flames, or even blow them out!

If there is any wind at your primary location don't even consider fire painting, it's a waste of time, energy and of course fuel - either find a location free from wind or regroup to another night when there is no wind.


In this example the wind picked up half way round the car and ruined the effect.


Ambient temperature and humidity.

If the ambient temperature is high it affects the temperature of the fuel, increasing ignition and also aids in the continuation of the combustion process, end result with high temperatures is a more intense flame.  The opposite can be said for cold ambient temperatures.

Also, If humidity is high it's harder for the moisture in the fuel to evaporate, reducing the flames intensity - the lower the humidity the easier it is to evaporate and thus you get a more intense flame.

The temperature of the fuel will also affect how it ignites, the colder it is the longer it will take to raise to the fuels ignition temperature, so on cold nights try and keep your fuel warmish before you soak the rope.

Tip: The flash point (when it ignites, aka ignition temperature) of paraffin is between 37 and 65 °C (100 and 150 °F)



Walking speed

The speed at which you walk, just like the wind affects how the rope or strap burns, too fast and it will nearly go out, too slow and the image will overexpose, unless of course you cater for this with your camera settings - we will come to this shortly.

Before going out on location, practise your walking speed, try to understand at what speed you can walk before the flames start to reduce, you ideally want maximum flame to achieve a "realistic" flame effect.

I have on a number of occasions had to slow down and speed up mid exposure, so keep an eye on the flames and adjust your walking speed accordingly.


Tip: When moving your wall or wave, try giving it a little wobble as you go, this will help the flame get more oxygen and break up the patterns, adding a more "realistic" flame effect.

 

Rope/strap

The thickness of the rope/strap is another factor to consider, if its thick it will hold more fuel and burn brighter for longer.  If you are using a thin rope/strap then the opposite will occur.  In both scenarios you will have to adjust your camera settings accordingly.

I use a combination of Kevlar Ropes and Straps, I would advise you go down this route.  As a temporary solution you could use a cotton based rope however, stay away from man made fibers, they will melt very quickly.

Tip: Always remember, do not to let your rope burn out! it damages the kevlar and reduces it's life - extinguish early and save your rope/strap.


Distance
As you can imagine the further away from the camera you are the less light will be picked up compared to when you are close.  You will find that settings (or the use of ND filters) that work at 5m will not give the same effect at 10m.  If you are doing a shot like the image below you will need to consider your walking speed, slowing down the further you get from the camera. 


Tip: When covering large areas the person holding the FHD will need to keep and eye on where they are walking, it's a good idea to have your assistant follow you and advise on how the flame is burning and shouting commands to slow down or speed up.

Camera settings

This is such a hard question to answer, generally there is no one fits all configuration, you have to be on top of your game, adjust settings quickly and adapt to the situation.

Firstly you should manually set the ISO to 100 and white balance to something static, leaving only aperture to experiment with.

Then close your aperture to something like F10, do a pass and check results if its over exposed close the aperture further and try again.  If your aperture is as small (f22) as it goes and you are still over exposing then its time for Neutral Density filters.  I've been know to use the 2, 4 or 8 - it all really depends on the current situation!

It would be best to ask your assistance to perform a few passes with the firewall, allowing you time to quickly adjust settings and find what works for your current situation.

Bear in mind, what worked in one situation may not work in another, always do a couple test passes to ensure you have the exposure just right or it's exposed enough so you can work with it in PP.

Below are some very basic examples of how settings affect the flames, these are all SOOC, no PP applied.  They were all shot at 24mm and about 3.5 meters from the firewall, the 3rd group of images sees the use of 3 different ND Filters.

f5,f16 and f22



f22/ND2, f22/ND4 and f22/ND8


   
Tip: One major point to bear in mind is the fact that you can never recover  from over exposure, you have much better chance to recover light from underexposed images, so don't forget to shoot in RAW!

Tip: During post processing you can try layering the exposure using screen, followed by some tweaking with new adjustment layers to maximise the effect and bring out some light.


Post Production
As we know, it is impossible to recover anything from over exposure, so make sure you under expose and recover the light in Post Production.  Here are a very quick and simple method to return some colour from an under exposed image.

Click images for a larger view.


Steps 

1. Let's use the wobble image from above, this is how it looks straight out of the camera
(settings WB:Flourescent, ISO:100, f/20 and used a ND8 Filter - Camera 3.5m from Firewall)


2. A few tweaks on import.

3. Now we duplicate the layer and set it to Screen, then we add the following New Adjustment Layers.
  • Brightness (-2) Contrast (16)
  • Vibrance (+1) Saturation (-3)
  • Hue and Saturation ((reds) Hue 0 Sat +41 Light -33)


4. Import into Lightroom, add some noise reduction and +70 on clarity and this is the final result.

Firewall Holding Device


The above images were captured using a
Firewall Holding Device, learn how to create one in aptly named blog "Firewall Holding Device"

 

Final thoughts.

As fire is such a volatile substance it can drastically be affected by the factors listed above there is however another consideration, you have bear in mind that the goal posts are constantly moving as the fuel burns off, learnt to adapt quickly to maximise each burn.

I think fire painting is akin to light painting with a torch that has a dodgy connection, causing the light to continuously flicker and change brightness  - this, in my eyes  is what makes fire painting such a unique challenge!


Fire painting comes down to trial and error, a little luck and finding what works for your specific requirements and situation, don't forget to have fun! - I hope this guide has helped you understand a little more about shooting a firewall, if not please don't hesitate to comment below or on my facebook page - any relevant questions will be added to a FaQ on this blog.

Before you go don't forget to head over to my Facebook Page and give it a like!

I now hand over to you, try to be creative and show us what you can do with your firewall! - Please post your results on my facebook page!

FAQ
Q: Which fuel do you use?
A: I only use paraffin.
 
Stay safe!


6 comments:

  1. Fantastic write up mate, great tips :)

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  2. hah really nice writeup. I learned a couple things too :D

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    Replies
    1. Thanks Ben, means a lot! - you know all of this is your fault, fire angel really inspired me to start playing with fire!

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  3. Fantastic Work !!! but i think your wrong with the idea to shoot underexposed ,i mean every digital sensor today archive much more data from highlights, if your camera says that at 0 EV ( a suposed right expose ) its something blowed up it doesent mean that in the RAW file that info doesnt exist, that the idea from Exposing to the Right. Again AWESOME work sorry for the little critic ;)

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  4. Where do you get paraffin fuel? I can only seem to find propane and naphtha coleman fuel.

    ReplyDelete