As with most modules in StarTools, the HDR module comes with a number of presets;
Going beyond the presets, very detailed adjustments can be made, starting with the 'Glow Threshold' parameter. This parameter is determines how bright a pixel needs to be before it is considered for diffraction by the Airy disk diffraction model.
To view just the model that Life is using to enhance the image, the 'Output Glow Only' parameter can be set to 'Yes'. Optionally this output can be used to manipulate the image later using the Layer module, or in a separate application.
The 'Strength' parameter governs the overall strength of the effect.
The 'Inherit Brightness, Color' parameter determines whether brightness or color information is inherited (and thus unchanged) from the source image.
The 'Saturation' parameter controls the colour saturation of the output model (viewable by setting 'Output Glow Only' to 'Yes'), before it is applied to the source image to generate the final output. This parameter can be quite effective for enhancing the color of nebulosity.
The 'Detail Preservation' parameter selects the detail preservation algorithm the Life module should use to merge the model with the source image to produce the output image;
The 'Detail Preservation Radius' sets a filter radius that is used for smoothly blending processed and non-processed pixels, according to the algorithm specified by the 'Detail Preservation' parameter.
The 'Compositing Algorithm' parameter defines how the calculated diffraction model is to be generally combined with the original image:
The 'Airy Disk Sampling' parameter controls the accuracy of the point spread function (PSF) that describes the diffraction model (an Airy disk).
The 'Airy Disk Radius' parameter sets the radius of the Airy disk point spread function (PSF) that is used to diffract the light. Just like in nature, you may spot some (very) subtle rings around the stars after processing. The way this looks can be adjusted using this setting.
Finally, as with most modules in StarTools that employ masks, a 'Mask Fuzz' parameter is available to smoothly blend the transition between masked and non-masked pixels.
Whatever detail lies outside the RoI, is simply forced to conform to the stretch that was designed for the RoI.
The desired crop is created by clicking and dragging with the mouse the area to retain.
It governs the range of detail sizes HDR should concentrate on, in order to bring out the most detail.
The Heal module was created to provide a means of substituting unwanted pixels in an neutral way.
You can convert everything you see to a format you find convenient. Give it a try!