Waid Observatory

Creating LRGB Images in Photoshop CS

CCD astronomical cameras utilize colored filters to create a color image.  Some cameras, known as one shot color cameras, have these filters built into the camera itself.  Other cameras use external filters to accomplish the task.  There are advantages and disadvantages to both types of cameras.  Most of the professional cameras use the external filter method.  This allows more flexibility and the cameras are generally more sensitive.  To create a color image with the external filtered cameras, one has to expose through each of three filters.  The usual filters are red, green, and blue. These three exposures are then combined to produce a master RGB color image.  A high-resolution grayscale image, referred to as a Luminance image and exposed without a color filter, can be combined with the RGB color image to yield a detailed final color image.  This final image is referred to as an LRGB image. This tutorial demonstrates how to create an LRGB image using Photoshop CS.

My tutorial is scaled for a browser resolution of 1024 X 768.  If the viewer is using Internet Explorer for a browser, I suggest pressing F11 before starting the tutorial.  This will allow an expanded browser window to show the tutorial without having to use the scroll bars.  After the tutorial finishes, press F11 again to restore the browser display to normal.  Use the "back" button to return to this page.

To start the tutorial click here.

Copyright Donald P. Waid