ComfyUI Node: ImageMagick Sigmoidal Contrast

ImageMagick Sigmoidal Contrast:

The ImageMagick Sigmoidal Contrast node is designed to enhance the contrast of an image using a sigmoidal function, which is particularly effective in preserving the details in both the shadows and highlights. This method adjusts the contrast in a way that mimics the response of photographic film, providing a more natural and visually appealing result. By applying a sigmoidal contrast adjustment, you can achieve a balanced enhancement that avoids the harshness often associated with linear contrast adjustments. This node is ideal for fine-tuning the contrast of your images to achieve a more dynamic and professional look.

ImageMagick Sigmoidal Contrast Input Parameters:

image

This parameter accepts the image that you want to apply the sigmoidal contrast adjustment to. The input should be in a compatible image format.

sharpen

This boolean parameter determines whether the image should be sharpened during the contrast adjustment process. The default value is True, meaning the image will be sharpened by default. Setting this to False will apply the contrast adjustment without sharpening.

strength

This float parameter controls the strength of the sigmoidal contrast adjustment. The value ranges from 0.0 to 1024, with a default value of 0.0. Increasing the strength will result in a more pronounced contrast adjustment.

midpoint

This float parameter sets the midpoint of the sigmoidal function, which affects the balance between the shadows and highlights. The value ranges from 0.0 to 1024, with a default value of 0.0. Adjusting the midpoint can help fine-tune the contrast effect to better suit your image.

channel

This parameter allows you to specify which color channel(s) the contrast adjustment should be applied to. Options include undefined, red, gray, cyan, green, magenta, blue, yellow, black, alpha, opacity, index, readmask, write_mask, meta, composite_channels, all_channels, true_alpha, rgb, rgb_channels, gray_channels, sync_channels, and default_channels. The default value is red.

ImageMagick Sigmoidal Contrast Output Parameters:

IMAGE

The output is the image with the sigmoidal contrast adjustment applied. This enhanced image will have improved contrast, with details in both shadows and highlights preserved, resulting in a more visually appealing and dynamic image.

ImageMagick Sigmoidal Contrast Usage Tips:

• Experiment with different strength and midpoint values to achieve the desired contrast effect. Start with small adjustments and gradually increase the values to see how they impact the image.
• Use the sharpen parameter to enhance the details in your image further. If the image appears too sharp, try setting sharpen to False.
• Apply the contrast adjustment to specific color channels using the channel parameter to target and enhance particular aspects of your image.

ImageMagick Sigmoidal Contrast Common Errors and Solutions:

Invalid image format

• Explanation: The input image is not in a compatible format.
• Solution: Ensure that the input image is in a supported format such as JPEG, PNG, or TIFF.

Strength value out of range

• Explanation: The strength parameter value is outside the allowed range of 0.0 to 1024. - Solution: Adjust the strength value to be within the specified range.

Midpoint value out of range

• Explanation: The midpoint parameter value is outside the allowed range of 0.0 to 1024. - Solution: Adjust the midpoint value to be within the specified range.

Invalid channel selection

• Explanation: The selected channel is not recognized or supported.
• Solution: Choose a valid channel from the provided options.