The size of a TIFF scan can be quite large compared to other formats like JPG, primarily because TIFF is a lossless file format. According to the reference provided, a typical slide scanned at 3000 dpi and saved in TIFF format would be about 70MB in size.
Understanding TIFF File Size
TIFF (Tagged Image File Format) is a robust and widely used image format, especially in professional photography, scanning, and publishing. Its key characteristic is being lossless, which means "the file is not compressed as it is with a JPG."
Why Are TIFF Scans Large?
- Lossless Quality: Unlike lossy formats like JPG, TIFF retains all the original image data. This ensures maximum quality and detail are preserved, making it ideal for archival purposes or when extensive editing is planned.
- No Compression (or Less Effective Compression): While TIFF can technically support some compression methods (like LZW), it is often saved without compression or uses methods that don't significantly reduce file size compared to formats optimized for smaller files (like JPG). The reference explicitly states, "these files are very, very large."
Comparison: TIFF vs. JPG
The provided reference offers a clear comparison demonstrating the size difference:
| Format | Typical Slide Scan (3000 dpi) | Compression Type |
|---|---|---|
| TIFF | About 70MB | Lossless |
| JPG | About 5MB | Lossy |
As shown, the same typical slide scanned at the same resolution results in a significantly larger file size when saved as TIFF (about 70MB) compared to JPG (about 5MB).
Factors Influencing TIFF Scan Size
While the reference gives a specific example, the actual size of a TIFF scan can vary based on several factors:
- Resolution (DPI): Higher resolution scans capture more detail and result in larger file sizes. The reference's example is based on 3000 dpi.
- Dimensions of the Source: Scanning a larger original document or image will naturally produce a larger file.
- Color Depth: Scans saved with higher color depth (e.g., 48-bit color) will be larger than those with lower depth (e.g., 24-bit color).
- Content Complexity: Images with more detail and color variations can sometimes lead to larger files, even in lossless formats, depending on internal structure.
- Compression Method (If Used): While often saved uncompressed, some TIFF files use lossless compression methods that might slightly reduce size, but still remain large compared to JPGs.
In summary, while the exact size varies, you should expect TIFF scans to be considerably larger than compressed formats like JPG due to their lossless nature, with a typical slide scan at 3000 dpi being around 70MB.
