Note: Hs-Art is a known developer of restoration and audio cleanup software (often associated with legacy Windows tools). The "Diamant Dustbuster" series is their specialized noise reduction suite. Since this is a niche, professional tool, this review is written assuming you have access to the actual full version.
Use the "Size Exclusion" slider. Dust is usually 1-15 pixels. The full version allows you to exclude anything larger (which might be a bird in the sky) or smaller (which might be film grain). Hs-Art Diamant Dustbuster 7 full version
: Replaced older blur/sharpen filters with a unified system that includes re-graining capabilities on individual color channels. Luminance De-flicker Note: Hs-Art is a known developer of restoration