Welding Glass and White Balance.

Earlier I was posting about using a Welding Glass as "ND" filter. As the Welding Glasses usually have a green tint (you can get gold or black aka. neutral as well... but that's quite hard) the picture will have a very strong green tone.

Out of Camera: Heavy Green Color Cast

Obviously shooting in RAW can give you the possibility to modify White Balance in Raw Development Software, such as Lightroom for Windows. The problem is that the green tint is so strong that it's almost impossible to get rid of it.

White Balance 'corrected' in Lightroom: Slight Green Color Cast

But is it possible to push LR further than it's normal possibilities? Obviously the answer is yes. With a custom color profile you can extend the White Balance possibilities of Adobe's Camera Raw (used by both Photoshop and Lightroom). Doing so you can get rid of the green color cast entirely.

Custom Camera Profile Used: No more green color cast

Comparison: Without the Welding Glass Filter

So how can you create the Custom Camera Profile for the Welding Glass?

It's very easy, you only need a white led torch. Usually they're going for 1 GBP on Ebay. So first you have to create the custom white balance in-camera. As I have a Pentax K-r I will write down the steps for this camera but it should be very similar on any other camera.

Step 1: Create a custom White Balance with the Welding Glass on

• Put the camera on a tripod if you can as you will need long shutter speed. What I did I turned the camera upwards so the torch will be in balance on the top of the Welding Glass.
• Find the correct exposure, where the torch does not get overexposed too much and it gives you a nice green "halo effect"
• Go to White Balance settings and choose Custom White Balance and press the Shutter. It will take the same picture you did earlier to find the exposure. When the camera requests find a spot on the picture where it has the green halo and move the little green square there. Press OK to accept it and your picture should turn grey now.
• Set this as your new White Balance and take a picture of real world with correct exposure. The picture should look OK, no sign of green tint.
• Make sure the picture is saved in DNG format!
  For other camera formats you will need to convert it to DNG with Adobe's DNG Converter

Step 2: Create the Custom Camera Profile

• Import the DNG picture into Adobe's DNG Profile Editor
• Go to the tab: Color Matrices
• You can play a little with the values there, for example I raised the Saturation for Red +50 and for Blue +25 and played a little with the White Balance as well untill I've got the picture I want.
• Go to Options tab and give your Profile a Name.
• In the menu go File and Export your Profile (you can do this by pressing CTRL+E)
• Save it to the folder:
  C:\Documents and Settings\\Application Data\Adobe\CameraRaw\CameraProfiles or ~/Library/Application Support/Adobe/CameraRaw/CameraProfiles/

Step 3: Use the Custom Camera Profile.

• In Lightroom:
  On the Develop Tab scroll down to Camera Calibration and choose your new Profile.
• In Photoshop:
  When opening a Raw file Camera Calibration is the third to last tab. It has an icon of a camera.

By having this Custom Camera Calibration Profile you can shoot with any White Balance, though you won't be able to see the 'real' colors on your camera.