What is HDR?

Radiance HDR is an image format that stores high dynamic range pixel data, commonly used for HDRI environment maps and lighting.

What is CPT?

Corel PHOTO-PAINT (CPT) is the native project format for Corel PHOTO-PAINT, preserving layers, masks, and editing history.

When Should You Use HDR vs CPT?

HDR vs CPT: Key Differences

• •HDR and CPT diverge on compression: lossless compression for the source, lossless compression for the target.
• •Both formats share lossless compression, so quality behavior is similar across the two — file size differences come from algorithm efficiency rather than compression philosophy.
• •How transparency is handled: CPT supports transparency, so alpha information is preserved during conversion.
• •Storage footprint: 5-30MB for typical HDR maps for HDR vs Large due to layer data for CPT.
• •HDR is optimized for hdri lighting, panoramic photography while CPT is designed for corel image editing, photo manipulation — choose based on your specific workflow needs

Advantages of HDR

• ✓At its core, HDR relies on lossless encoding — a design choice that makes it perfect for HDRI lighting, panoramic photography.
• ✓You won't run into compatibility issues with HDR — it's a universal standard across platforms.
• ✓File size management with HDR: larger files guaranteed to match the original exactly.
• ✓Every major application in the HDRI lighting, panoramic photography space supports HDR natively.

Advantages of CPT

• ✓CPT applies lossless compression specifically calibrated for Corel image editing, photo manipulation.
• ✓CPT enjoys broad native support across operating systems, browsers, and creative tools alike.
• ✓CPT guarantees every bit of the original data survives — no approximations, no shortcuts.
• ✓You will find CPT support built into virtually every tool that handles Corel image editing, photo manipulation — no plugins or converters needed.

Common Use Cases for HDR to CPT Conversion

• Websites and online content
• Print materials and publications
• Social media posts and ads
• Digital photography and editing
• Graphic design projects
• E-commerce product images

Industry Applications

Best Practices for HDR to CPT Conversion

• →Before converting HDR to CPT, decide whether you need maximum quality or smallest file size — this determines which format truly fits
• →Save a master copy in a lossless format before converting to CPT — you cannot recover detail lost during lossy compression
• →Check the color profile: HDR images may use a wider gamut than CPT supports, causing a visible shift after conversion
• →Resize images to the final display dimensions before converting — this avoids unnecessary processing of oversized files
• →Run a single test conversion first to verify quality meets your standards
• →Strip unnecessary metadata to reduce file size after conversion

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Troubleshooting HDR to CPT Conversion

• !Converting HDR to CPT gives blurry output → increase the quality setting before conversion
• !Colors look different in CPT than HDR → check color profile mismatch (sRGB vs Adobe RGB)
• !File size changed more than expected → CPT uses different compression, file size differences of 2-5x are normal
• !Transparent areas in HDR turned white in CPT → CPT may not support transparency

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