Tutorial:
DSLR cameras RGB multipliers

Content:

1. Introduction
2. Download DCRaw and copy to a folder
3. Open Command Window
4. Change directory in Command Window
5. DCRaw parameters
6. Get cameras RGB multipliers or white balance values

1: Introduction

When working with a DSLR color camera it could be a bit frustration to have correct colors on the final astroimage. If you know what your DLSR camera think is a natural looking image it would be easier. With the tool DCRaw you can get information from your camera's multipliers it use to the three color channels.

Why this? The sensor in the camera doesn't have equal sensitiveness to different color or wave lengths. And the white balance also depends of the lighting conditions. In the case of stars and astrophotography the daylight setting could be close for a unmodified DSLR camera.

I normally have the camera set to daylight white balance. With that setting you will get close to our Sun's color as a light source. Sun is a star so maybe don't too stupid.

Important:
The White Balance doesn't alter the raw image, but the RGB multiplier (scaling) values are written in the header to let the image program know how to color balance the image. It's those values we are looking for.

Note:
It only works for an unmodified camera! Or maybe for a factory built astro camera like a Canon 20Da, I don't know for sure.