Quality degradation with each encode or export — especially visible in compressed formats. Every generation strips sharpness, color, detail.
Every time you encode, export, or convert a file, you lose information. This isn't philosophy, it's physics. With uncompressed raw data, you won't notice it. But as soon as compression comes into play—and it always does when data actually needs to travel over networks or fit onto storage—the damage accumulates. After the first compression, you've already lost pixels, reduced color depth, and rasterized transitions. If you export from an already compressed file, all of this happens again. With each pass, the image becomes flatter, the colors more distorted, the edges sharper.
In daily production, you'll see this most clearly with proxy workflows or multiple rendering passes. You shoot in ProRes or h.265, edit with it, export to the VFX department, they come back with change requests, you re-export—and during the final render, you notice: the fine hairs are no longer there, skin tones look blotchy, the sky gradient looks digitized. This isn't a hardware error. This is accumulated generation loss. It becomes particularly brutal when you work with h.264 or older codecs—these formats are aggressive compressors. Every export costs you luminance information, every color sampling is further reduced.
Prevention is pragmatic: work with uncompressed or lightly compressed sources (DNxHD, ProRes, CinemaDNG) for as long as possible. Batch your exports—don't render the same file ten times, but do it right once. Use intermediate formats only when necessary, not as a standard workflow. And if you know multiple re-encodes are pending, factor that in from the start: more color headroom, stronger contrasts, so the degradation doesn't clip to black or white. Some DoPs consciously build in overexposure in certain channels for this scenario.
In the color suite, generation loss becomes a nemesis—you'll see that a four-pass export from a LUT application and grading looks significantly flatter than the original timeline. This is where mastering files become valuable: you save the final color version in the maximum colorspace (DPX, OpenEXR), and generate all distribution versions from there. This breaks the chain of loss and prevents multiple generation hits from stacking up.