ComfyUI Node: ◎ Radiance HDR Tone Map

◎ Radiance HDR Tone Map:

HDRToneMap is a professional-grade node designed for high dynamic range (HDR) tone mapping, offering a range of presets and advanced controls to enhance your images. This node is GPU-accelerated, ensuring efficient processing of complex HDR images. The primary goal of HDRToneMap is to convert HDR images, which often contain a wide range of luminance levels, into a format that can be displayed on standard displays without losing detail in the highlights and shadows. By applying various tone mapping operators, such as filmic and reinhard, HDRToneMap allows you to achieve a balanced and visually appealing image that retains the dynamic range and detail of the original HDR content. This node is particularly beneficial for AI artists looking to refine their HDR images with precision and creativity.

◎ Radiance HDR Tone Map Input Parameters:

operator

The operator parameter determines the tone mapping algorithm applied to the image. Options include "filmic_aces", "filmic_uncharted2", "agx", "reinhard", "reinhard_extended", and "reinhard_luminance". Each operator offers a unique approach to tone mapping, affecting the contrast, color balance, and overall appearance of the image. Selecting the appropriate operator can significantly impact the final visual output, allowing you to tailor the tone mapping process to your specific artistic needs.

highlight_recovery

highlight_recovery is a parameter that controls the extent to which highlights are recovered in the image. It ranges from 0 to 1, where 0 means no recovery and 1 means full recovery. This parameter is crucial for preserving details in the brightest parts of the image, preventing them from appearing washed out or clipped.

highlight_rolloff

The highlight_rolloff parameter adjusts the softness of the transition between normal and expanded dynamic range areas. It typically ranges from 1.0 to 3.0, with higher values resulting in a softer transition. This parameter helps in achieving a more natural look by smoothing out the highlight areas, making the expansion less abrupt.

shadow_lift

shadow_lift is used to brighten the darker areas of the image. It ranges from 0 to 1, where 0 means no lift and 1 means maximum lift. This parameter is useful for revealing details in the shadows without affecting the midtones and highlights, enhancing the overall visibility of the image.

target_stops

The target_stops parameter defines the target peak luminance level in stops, which influences the dynamic range expansion. It is calculated as 2^(stops

• 8), with higher values indicating a greater dynamic range. This parameter is essential for setting the desired brightness level of the image, ensuring that it fits within the displayable range.

◎ Radiance HDR Tone Map Output Parameters:

linear

The linear output parameter represents the tone-mapped image in a linear color space. This output is crucial for further processing or display, as it contains the adjusted luminance values that have been mapped from the HDR input to a standard dynamic range. The linear output ensures that the image retains its visual integrity and detail after tone mapping.

◎ Radiance HDR Tone Map Usage Tips:

• Experiment with different operator settings to find the tone mapping style that best suits your artistic vision. Each operator offers a distinct look and feel.
• Use highlight_recovery to preserve details in bright areas, especially when working with images that have significant highlight content.
• Adjust highlight_rolloff to achieve a smooth transition in highlight areas, which can help in creating a more natural and pleasing image.
• Utilize shadow_lift to enhance shadow details without overexposing the rest of the image, providing a balanced exposure.

◎ Radiance HDR Tone Map Common Errors and Solutions:

"Invalid operator selected"

• Explanation: This error occurs when an unsupported tone mapping operator is chosen.
• Solution: Ensure that the operator parameter is set to one of the supported options: "filmic_aces", "filmic_uncharted2", "agx", "reinhard", "reinhard_extended", or "reinhard_luminance".

"Highlight recovery value out of range"

• Explanation: This error indicates that the highlight_recovery parameter is set outside its valid range of 0 to 1. - Solution: Adjust the highlight_recovery parameter to a value within the 0 to 1 range.

"Shadow lift value out of range"

• Explanation: This error suggests that the shadow_lift parameter is set outside its valid range of 0 to 1.
• Solution: Modify the shadow_lift parameter to a value within the 0 to 1 range.