Why does a PDF look blurry as an image? Choose pages, pixels, and format

Compare the original and the downloaded image

If the PDF is sharp but the image becomes blurry when enlarged, the image may have too few pixels for the intended use. Choose a higher rendering resolution and compare the result. If the original scan is already blurry, raising the output resolution makes a larger image of the same limited detail.

Start with one representative page containing small text, a table, or fine lines. Download it and inspect it at its intended display size, plus a 100% view. A thumbnail scaled to fit the browser is not enough to judge a large slide or printed page.

What you observe	What to investigate	Next step
Text is sharp in the PDF but pixelated in the enlarged image	Output pixel count	Increase rendering resolution or keep the PDF
Both source and output show fuzzy text	Source scan quality	Find a better scan or original document
A few letters, lines, or objects are missing	Rendering of that PDF	Compare the same page carefully before using the output
A long conversion fails or becomes slow	Page selection and processing load	Try fewer pages or a lower resolution

These are diagnostic starting points, not automatic conclusions about a particular file.

Relate the resolution setting to actual pixels

Tooliv offers 72, 144, and 300 DPI rendering options, with 144 as the default. The setting determines how many pixels are used to draw the page. Mozilla’s PDF.js examples explain how a page viewport and rendering scale control the output dimensions.

For an ordinary 8.5 × 11 inch US Letter page with standard PDF units and no rotated orientation, the calculated dimensions are:

Rendering setting	Width × height	Total pixels
72 DPI	612 × 792	484,704
144 DPI	1,224 × 1,584	1,938,816
300 DPI	2,550 × 3,300	8,415,000

The calculation is page length in inches × rendering DPI, applied to each axis. Actual PDF page boxes, rotation, and rounding can change the final dimensions. These numbers are a worked calculation, not the result of running a PDF through every browser.

Doubling the resolution doubles each side and quadruples the pixel count. More pixels therefore increase the processing work much faster than the label alone might suggest. They do not guarantee a fixed file size or a proportional improvement in readability.

Choose for the destination

For a small on-screen illustration, compare a lower setting first. For a page that must be read closely or printed, inspect a higher-resolution candidate. Use the smallest result that still meets the required dimensions and legibility, rather than automatically rendering every page at the highest setting.

For print, calculate effective PPI from the output pixels and the size at which they will be placed. The print-resolution walkthrough gives the formulas and cropping examples. If the print service accepts the original PDF, retaining it may avoid an unnecessary raster conversion.

The downloaded file’s properties may show a resolution label different from the rendering option. Canvas image export can write 96 DPI metadata in formats that support it, as MDN documents. Check actual pixel dimensions and final placement size before assuming the rendering failed.

For a scanned page, rendering more pixels cannot restore source detail that was never captured. Adobe’s resampling explanation distinguishes adding estimated pixels from recovering original information.

Select only the pages you need

Choose all pages or enter a range such as 1-3,5. The numbers refer to positions in the PDF, starting at 1. A printed page number may differ if the file includes a cover or introductory pages. Duplicate selections are removed and results follow document order.

Select PNG or JPEG and start the conversion explicitly. PNG is the default; JPEG uses a quality setting of 90%. Both render onto a white background. Compare JPEG carefully around fine text and lines rather than assuming it is always an appropriate smaller substitute.

If the document requires a password, enter it in the provided field. Changing the file or conversion settings clears that run’s results. Cancel also clears the current run, so download any results you intend to keep before starting a different selection.

Keep the processing limits in mind

The tool accepts one PDF up to 50,000,000 bytes and at most 100 selected pages. Large page dimensions can reach the pixel limits before the page-count limit: 16 million pixels for one page and 150 million across the selection. Generated image files also have a combined 200,000,000-byte limit.

These limits are safeguards, not a promise that every qualifying PDF will finish on every device. Complex content and available browser memory can still affect processing. For a difficult document, select one page, verify it, then increase the batch gradually. A large document can be processed in selections without rendering every page at once.

Verify the downloaded set

Use individual page downloads or the ZIP download for the completed set. Compare filenames and page numbers against the requested range, then inspect the downloaded images rather than only the on-page previews.

An image does not retain selectable PDF text, working links, or interactive fields. This converter also does not perform OCR. For editable text, consider the document conversion workflow and check whether the PDF has a usable text layer.

If the page images will be uploaded elsewhere, finish with the image submission checks: accepted format, pixel dimensions, bytes, and required visible content.