The Process of Building RGBs

graphic with 8 RGB images from the DMSP OLS, Meteosat SEVIRI, and Metop AVHRR satellite imagers

The process of building RGBs is part science and part art, part random exploration and part methodical experimentation. Over time, a set of best practices has been established to guide the development process. While some good RGBs arise from random experimentation, your best chance of making a useful product will result from following an established procedure. Even if you never experiment with RGB compositing, being aware of the process will help you better understand and interpret the products.

The process of building an RGB has five steps.

  • Step 1: Determine the purpose of the product
  • Step 2: Based on experience or scientific information, select three appropriate channels or channel derivatives (such as an inter-channel difference) that provide useful information for the product
  • Step 3: Pre-process the images as needed to ensure that they provide or emphasize the most useful information
  • Step 4: Assign the three spectral channels or channel derivatives to the three RGB color components
  • Step 5: Review the resulting product for appearance and effectiveness

We will examine the steps on the following pages, applying them to build two products: the natural color RGB and the dust RGB.