Image Format Checklist for Scanned Documents
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Overview
Choosing an image format for scanned documents requires more than selecting the smallest file. Text legibility, line art, photographic areas, color, multipage structure, metadata, downstream software, and retention policy can all matter. A good checklist separates the preservation source from convenient access copies.
TIFF, PNG, and JPG can each be appropriate, but they serve different roles. The live ForgeConvert workflow handles one decoded frame and strips normal output metadata, so it should create reviewed derivatives rather than silently replace a multipage or metadata-dependent scan master.
Assess the source scan
Record pixel dimensions, orientation, color mode, visible text quality, page count, and whether the file carries metadata required by an archive or business process. Inspect faint marks, stamps, signatures, and halftone photographs before deciding what can change.
Determine whether the source is a preservation master, an editing intermediate, or an access copy. A TIFF created by scanning software may belong in the first category, while PNG can suit lossless single-page graphics and JPG can suit compact photographic access.
Treat multipage files carefully
A single-frame conversion does not represent every page of a multipage source. Preserve the original container and verify page handling before creating any derivative for distribution.
Select a destination deliberately
Choose PNG when a single scanned page contains text, line art, or flat graphics that benefit from lossless decoded pixels. Choose JPG for an opaque access copy when photographic content and broad compatibility outweigh the need for lossless storage.
Choose TIFF when the receiving professional workflow explicitly requires it and its expected compression and metadata conventions are known. The extension alone does not establish archival suitability, so institutional requirements should govern preservation decisions.
Verify the derivative before use
Open the downloaded file in the target document system, zoom into small text and fine lines, and compare orientation, dimensions, contrast, color, and page identity with the source. Confirm that required metadata was not assumed to transfer.
Keep the original scan, document the conversion purpose, and test a representative page before processing a batch. If optical character recognition, cleanup, deskewing, or resizing is required, use a separate specialist workflow because ordinary format conversion does not perform those operations. Record the source filename, chosen derivative, page identity, and receiving system so another reviewer can trace the relationship later. For sensitive records, follow the organization's established retention and access rules rather than inventing a new policy during conversion. Preserve a clear review record as well.
Format capability and current encoder policy
TIFF format capability
As a file format, TIFF is a flexible raster container commonly used for high-fidelity interchange and archival workflows. Normally lossless in ForgeConvert; output files can be large. It is best suited to print production, scanning, and master images where file size is secondary. These capabilities describe the format itself, not a promise about a particular encoder.
Current ForgeConvert TIFF output policy
Lossless LZW compression creates a high-fidelity TIFF. Normal output metadata is stripped.
PNG format capability
As a file format, PNG stores raster graphics losslessly and can preserve an alpha transparency channel. Lossless; photographic files can be large. It is best suited to logos, screenshots, diagrams, and graphics with transparent edges. These capabilities describe the format itself, not a promise about a particular encoder.
Current ForgeConvert PNG output policy
Lossless PNG encoding preserves decoded pixel values and alpha. Normal output metadata is stripped.
JPG format capability
As a file format, JPEG uses lossy compression to keep photographic files compact and broadly compatible. Lossy; repeated encoding can add artifacts. It is best suited to photographs, email attachments, and images that must open almost anywhere. These capabilities describe the format itself, not a promise about a particular encoder.
Current ForgeConvert JPG output policy
Encoded at quality 82 with 4:2:0 chroma subsampling. Normal output metadata is stripped.
For Image Format Checklist for Scanned Documents, the current workflow does not permanently store uploaded or converted files, accepts up to 20 files of 8 MB each, limits decoded images to 40 megapixels, and allows 15 seconds for processing. These operating limits come from the active converter configuration.
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See also
Frequently asked questions
Is TIFF always the best archival scan format?
Not automatically. Archival suitability depends on the actual file, metadata, compression, color, and the receiving institution's requirements.
Can a multipage TIFF become one complete PNG?
A single-frame conversion cannot preserve an entire multipage structure, so the original TIFF must be retained.
Does converting a scan perform OCR?
No. Format conversion does not recognize text, deskew pages, clean backgrounds, resize images, or create searchable documents.