Convert RGB

This command converts RGB-encoded raw images, such as those from DSLR "raw" (.CRW, .NEF) files, to a color image. These are monochrome images in that they contain only a single plane of data but are actually encoded with RGB information in adjacent pixels. Using this command on images that are not RGB encoded will produce gibberish. For CMYG-encoded cameras, please see Convert CMY.

These sensors have an alternating pattern of color dyes in front of the pixels. The Convert RGB command converts this color information into the standard RGB color plane format used by MaxDSLR and other programs, and provides for color balancing.

The Debayer Mode selector allows you to choose the algorithm used to perform the color conversion. The Fast mode will produce reasonable color quality at a decent speed. The High-Quality mode takes longer to convert the image, but produces images with fewer artifacts from the conversion process.

Color images from DSLRs and CCD cameras typically require a background level adjustment. This is accomplished by bringing the background level (or bias) in each color plane down to zero. Each of the Background Level values is subtracted from every image pixel in its color plane. Any pixel values that become negative are forced to zero. The Reset button resets the background subtraction to zero on all planes, and disables the Auto setting. When the Auto setting is enabled and the conversion settings change, the dialog automatically determines the settings necessary to equalize the image background in all three color planes.

The Scaling % adjustments allows you to compensate for differing sensitivity between the color planes. Values of 100% result in no change. The scaling adjustments can be typed in or adjusted using the spin controls. The Preview Image is particularly helpful in monitoring the results when using the sliders. The Reset Scaling button resets to 100% on all three planes.

The X Offset and Y Offset selections are used to correct for any misalignment of the color mask in the camera. Normally these are turned off. If the converted images exhibit an obvious color imbalance, try selecting different combinations of these two options.

In most situations, enabling the Auto background level option will help you to obtain accurate colors. When enabled, the image's background levels are re-calculated whenever any setting changes which may have affected the previous background measurement. If the setting is disabled, then the values must be entered manually. Manual changes to the background level settings will automatically disable the Auto background setting. Further adjustments to the color balance can be made using the Color Balance command.

Note that the color response of each camera model is slightly different, depending on the quantum efficiency curve of the sensor, and the passband of the color filter materials used. Color is subjective and since humans cannot see color at the brightness levels of most astronomical objects, we must try to present the images we capture with a pleasing color balance consistent with the light response on the sensor compared to daylight photography. The following table gives some starting points for some DSLR cameras based on the light response with the factory IR filters installed. This is intended as a starting point, you should adjust the color balance to get the results that you believe best represent the objects.