EXR vs PNG vs JPEG: When You Need Float Pixels

Bit Depth Matters

The fundamental difference between EXR and PNG/JPEG comes down to bit depth — how many bits are used to store each color channel:

• PNG (8-bit per channel): 256 possible values (0–255). Sufficient for standard display but clips any value above 255.
• EXR (16-bit half or 32-bit float per channel): 65,536+ possible values with HDR range. A single pixel can store values from −∞ to +∞.

This isn't just about "more detail." It's about preserving information that would be permanently lost during quantization (rounding to 8-bit integers). In a render, specular highlights or light sources often exceed 255 — they might have values of 1024, 4096, or higher. PNG would clamp these to exactly 255; EXR stores the actual value.

HDR Headroom

HDR (high-dynamic-range) headroom is why VFX and CGI pipelines use EXR. Here's what happens when you convert an EXR to PNG:

• Highlights are clipped: any pixel channel above 1.0 (in float) gets clamped to 1.0 (=255 in PNG). Soft highlights become hard-edged blocks of pure white.
• Shadow detail is lost: tiny differences between values like 0.004 and 0.005 become identical (both round to the same 8-bit value).
• Color bleeding in compositing: when you composite layers with clipped highlights, color bleeding occurs at edges where values were rounded.

JPEG: Lossy Compression

JPEG adds another layer of degradation beyond PNG's 8-bit limitation:

• Lossy compression artifacts: JPEG discards data using discrete cosine transforms. This is fine for photographs but devastating for clean CG renders with sharp edges and gradients.
• No alpha channel support: JPEG doesn't store transparency information at all.
• Chroma subsampling: JPEG often reduces color resolution to save space, which can cause color fringing in renders.

When to Use Each Format

Bottom Line

If you're working in a VFX or CG pipeline, EXR is non-negotiable for intermediate files. PNG and JPEG are fine for final delivery — but only after all compositing work is complete. Never use PNG or JPEG as an intermediate format because the data loss is irreversible.

The Online EXR Viewer lets you open and inspect any EXR file directly in your browser, with exposure and gamma controls to preview HDR content correctly on a standard monitor.