Is quality 100 truly lossless?

No. Quality 100 is still lossy because the JPEG algorithm always rounds DCT coefficients. The only lossless JPEG mode is rarely supported. For true lossless output, use PNG.

What DPI should I use with quality 90?

The PDF to JPG tool uses 150 DPI with quality 90. For screen viewing, 150 DPI is adequate. For printing, 300 DPI is common, but the quality setting remains the same.

Why does my colored text look blurry in JPEG?

Chroma subsampling (4:2:0) reduces color resolution. This can blur colored text edges. To avoid it, use PNG or a JPEG encoder that supports 4:4:4 subsampling (full color).

How many times can I re save a JPEG before the text becomes unreadable?

Each save adds more artifacts. After 5 to 10 saves at quality 90, text may show visible ringing. After 20 saves, small text can become hard to read. Always keep a PNG original.

JPG Quality Settings for Document Pages: 60, 75, 90 or 100?

For document pages with text, set JPG quality to a high level. Quality 100 still loses data. Lower settings smear letters with visible noise. The jpg quality setting for documents controls that trade-off between file size and readability.

What the JPG Quality Number Actually Means

The JPG quality slider runs from 1 to 100, but it is not a percentage of the original image quality. It is an encoder setting that controls how much detail gets discarded during compression. JPEG divides the image into 8x8 pixel blocks and applies the discrete cosine transform (DCT). The quality number tells the encoder how aggressively to simplify the DCT coefficients. A higher number means less simplification, but even quality 100 is still lossy. For text pages, compression hits sharp edges harder than smooth areas.

Where Compression Damage Shows Up on Text Pages

Compression damage appears most around sharp edges, which is exactly what text consists of. Two common artefacts are ringing and mosquito noise. Ringing looks like faint ghost echoes next to letter strokes. Mosquito noise is a scattered blur around the edges of characters. Both worsen as the quality number drops.

Watch Chroma Subsampling on Coloured Pages

Many JPEG encoders use 4:2:0 subsampling, which stores colour at half resolution in both directions. For black text on white, this rarely matters. For coloured text or coloured backgrounds, subsampling can blur the edges of letters, making them harder to read. The quality setting does not control subsampling directly, but some tools apply subsampling only at lower quality levels.

Quality 60 Noticeable Loss on Text

At a low quality setting, the encoder discards a significant amount of detail. On a page of text, you will see ringing around most letters, especially at smaller font sizes. Mosquito noise can make the page look dirty. For archival or printing purposes, such a low setting is too low. Use it only for quick previews or thumbnails where file size is the top priority.

Quality 75 a Trade-Off for Small Files

A moderate quality setting is a common default in many image tools. For text pages, damage is still visible but less distracting than at lower settings. Larger text (a few points or above) may look clean. Smaller fonts and fine details like punctuation marks can show ringing. The site's PDF Compressor re-renders pages at 110 DPI and a similar quality setting, a similar trade-off for reducing file size while keeping most text readable.

Quality 90 the Sensible Default for Text

A high quality setting offers a strong balance between file size and readability. At this setting, damage is barely visible even on small text. The 8x8 block boundaries do not show, and ringing is minimal. For scanned documents, a high quality setting preserves the sharpness of original typewriter or printed text without producing overly large files. The PDF to JPG tool on this site uses a high quality setting at 150 DPI, a good starting point for most document conversions.

Quality 90 Versus 100

When comparing jpeg quality 90 vs 100, the difference in file size is often significant. The visual difference on text is negligible. Quality 100 is still lossy and can produce files several times larger without a visible improvement on a typical document page.

Quality 100 Still Lossy, Usually Unnecessary

Quality 100 tells the encoder to preserve as much detail as possible, but it is not lossless. The DCT step still rounds coefficients, and chroma subsampling may still be applied. For text, quality 100 gives no visible benefit over a high quality setting, but the file size can be two to three times larger. Reserve it for when you plan to edit the JPG later and want to minimise generation loss from re-saving.

Generation Loss and Repeated Saving

Every time you open and re-save a JPEG, you add more loss. This is called generation loss. Each save applies a new round of DCT and quantisation, so damage accumulates. If you need to edit a document page multiple times, save the original as a PNG first. PNG is lossless and avoids all JPEG damage, though file sizes are larger. For final distribution as JPG, save once at a high quality setting.

How to Choose the Right Setting

For text-only documents with small fonts, use a high quality setting.
For scanned documents with mixed text and line art, a high quality setting works well.
If file size is critical and you can tolerate slight damage, try a moderate quality setting.
For archival copies you may re-edit, save a PNG master and export JPG at a high quality setting.

The best jpg quality for scanned documents is a high setting. It preserves text clarity without unnecessary file size. The jpeg compression artifacts text issue is most visible below a moderate quality setting. If you see ringing or mosquito noise, increase the quality setting. Chroma subsampling text can blur coloured text, so if your document uses colour, check that the encoder uses 4:4:4 subsampling (full colour resolution) or stick with PNG.