Polishing the Stars: Final Touches with Photoshop & External Tools

Introduction

After completing the core PixInsight workflow, your image is likely 95% complete. But sometimes, that last 5% — the polish — makes all the difference. This is where Photoshop and external tools come in, giving you the flexibility to make subtle artistic adjustments while preserving all the scientific integrity of your data.

1️⃣ When to Export from PixInsight

• File format: Export as a 16-bit TIFF for maximum compatibility. PSD is fine if you’re working exclusively in Photoshop.
• Colour profile: Embed an sRGB profile for web output or AdobeRGB (1998) if you plan on printing.
• Bit depth: Stick with 16-bit to retain dynamic range unless you’re specifically working with 32-bit HDR workflows.

💡 Tip: If you’re planning to continue in Photoshop with adjustment layers, make sure to keep your file uncompressed to avoid data loss.

2️⃣ Preparing the Image in Photoshop

• Open your TIFF/PSD in Photoshop.
• Immediately duplicate the background layer (Ctrl/Cmd+J) so your edits are non-destructive.
• Consider converting to a Smart Object so you can apply filters like Camera Raw non-destructively.

3️⃣ Camera Raw Filter: The Finishing Touch Toolkit

Go to Filter > Camera Raw Filter to open one of Photoshop’s most versatile adjustment panels.

Inside Camera Raw you can:

• Recover blown highlights: Use the Highlights slider to pull back detail in bright star cores or nebula regions.
• Set the black point: Adjust the Blacks slider to deepen contrast without clipping faint details.
• Boost clarity and vibrancy: Increase Clarity to add local contrast to dust lanes or nebula edges, and Vibrance for subtle colour enhancement without oversaturating.
• Texture slider: Adds definition to fine details without affecting the stars too harshly.
• Colour grading: Use the colour mixer to fine-tune individual hues, especially if you want to correct subtle casts in nebulae.

💡 Tip: Work in moderation. Camera Raw is powerful, but it’s easy to overdo adjustments and lose the natural feel of the image.

4️⃣ Subtle Enhancements with Adjustment Layers

• Curves: Add gentle contrast by creating an S-curve. Use luminosity masks to apply only to faint nebula structures.
• Selective colour: Fine-tune specific channels (e.g. cyan and magenta in emission nebulae).
• Dodging and burning: Lightly paint highlights and shadows to guide the viewer’s eye through the image.

5️⃣ Optional Plugins & Tools

• Nik Collection: Great for tonal contrast and fine control over micro-structures.
• Topaz DeNoise AI: For any residual noise, especially in faint dust regions.
• StarSpikes Pro 4: Add realistic star diffraction spikes for an artistic finish. We’ll cover this in detail in January’s dedicated article.

6️⃣ Sharpening for Output

• Apply final sharpening only at the end.
• For web: Use Unsharp Mask with low radius (~0.3–0.5) and moderate amount.
• For print: Use Smart Sharpen or high-pass sharpening on a separate layer.

💡 Tip: Always view at 100% zoom when sharpening and check for ringing artefacts around stars.

7️⃣ The Art of Subtlety

The goal of this stage is not to redo your processing, but to add the final layer of polish. Keep a copy of the original PixInsight export for reference, and if you find yourself making huge changes, it may be a sign to revisit the PixInsight workflow instead of over-correcting in Photoshop.

Conclusion

With these final touches, your image transitions from processed data to a true work of art, ready for sharing or printing. This stage concludes the core workflow series and bridges the gap between scientific accuracy and artistic expression.