Lecture Notes: Affinity Photo and SETI Astro

Introduction

• Discussion on bit depths in Affinity Photo.
• Focus on exporting images for use with Cosmic Clarity, Sharpen, and Denoise.

Export Options in Affinity Photo

• Navigate to File > Export to access export settings.
• Advanced Features allow saving as 32-bit RGB.

Issues with 32-bit Output

• Successfully exported a 32-bit unsigned TIFF.
• Encountered problems when opening the saved file in PixInsight:
  • Image appeared grayish.
  • Histogram showed limited data (indicating possible 16-bit storage).
• Experimented with a snippet of code to analyze TIFF metadata, revealing:
  • Image saved as "integer 32 bits".
  • Color space indicated as 16-bit (XFTAG color space: 65, 535).
  • Data stored in a 32-bit architecture but effectively 16-bit.

Conclusion on Exporting

• Key Finding: Cosmic Clarity struggles with 32-bit images that are actually 16-bit.
• Recommendation: Save images as 16-bit RGB TIFF instead of 32-bit to avoid issues.
• Successful run of Cosmic Clarity with 16-bit TIFF produced smooth histograms, unlike the jagged ones from the 32-bit TIFF.

Final Advice

• Users of Affinity Photo should focus on 16-bit exporting for compatibility.
• Avoid 32-bit TIFF exports as they only lead to larger file sizes without real benefits.

Call to Action

• Encourage comments, likes, and subscriptions from the audience.