A PDF is a container; putting a raster image inside it does not restore detail that was absent from the source. An image can look soft because it was placed too large, cropped, downsampled on export or already lacked detail. Diagnose each placed image’s effective PPI at its final size, then compare that value with the print provider’s requirements. A print-oriented PDF export cannot repair a low-detail source.
Trace softness to the placed image
Effective PPI describes how many source pixels are available per inch at the image’s placed physical size. For each direction, divide the usable pixel dimension by the placed size in inches. Use the remaining pixels after any crop, not the dimensions of an uncropped original. Enlarging the image on a page lowers its effective PPI; reducing it raises that ratio but does not create new image detail.
This is a placement diagnosis, not a substitute for planning source pixel dimensions for a physical print size. Decision checkpoint 1: First determine whether the softness is in the original image, appears only after placement, or appears only in the PDF viewer. Those causes call for different fixes.
Inspect placement and export in sequence
Use an external layout application and, where available, an external PDF preflight tool. Imagild’s image preview does not replace checks of the placed raster inside a print PDF.
- Inspect the source image at a useful close view. If its edges and details are already soft, changing the PDF container will not restore them; revisit the source artwork or its available resolution.
- Select each placed raster in the layout and note its crop, pixel dimensions and physical width and height. Calculate effective PPI from the retained pixels and actual placed size in each direction.
- Compare the calculated values with the specification from the printer or print provider. Do not assume one universal minimum: requirements can vary with process, size and viewing distance.
- Export the PDF using the requested settings, then inspect the exported file. Check whether the placed image was downsampled, whether the crop changed and whether softness is visible in the embedded image at the intended output size.
Decision checkpoint 2: If the source looks detailed but the placed image’s effective PPI falls below the provider’s requirement, reduce its physical size or replace it with a more suitable source. If the source itself is soft, scaling it down may make the softness less obvious but does not restore missing information.
Separate image detail from PDF viewing artifacts
A PDF viewer may display a temporary soft preview while rendering or scaling the page. Compare the source, the placed image and the exported PDF at a consistent magnification before deciding the artwork is defective. If the PDF preflight shows adequate image data but the viewer alone looks soft, check the PDF at print size or ask the provider to inspect the file. If all placed rasters look soft after export, review export downsampling and compression settings with the layout workflow.
Check crops individually: an image can have enough pixels overall but too few pixels in the portion left after a tight crop. Decision checkpoint 3: Use the preflight or provider’s stated requirement—not the phrase print PDF in an export menu—as the acceptance standard.
Fictional planning example: Jo’s product-page image
This is a fictional planning example, not a generation experiment. Jo places a square product image into a print layout and notices that its small label appears soft in the PDF. Jo checks the original image at close view, records the crop and placed dimensions, and calculates effective PPI from the retained pixels. Jo then compares the exported PDF with the source and checks the printer’s specification. The observable checks help distinguish a soft source from enlargement, a tight crop, export downsampling or viewer rendering before Jo chooses a correction.
Does exporting as PDF Print increase an image’s detail?
No. An export setting may affect how image data is handled, but it cannot recreate detail missing from the source raster.
Is effective PPI the same as the image’s pixel dimensions?
No. Pixel dimensions describe the raster; effective PPI depends on how many of those pixels remain after cropping and how large the image is placed.
What PPI should every print image have?
Ask the print provider for the requirement for your job. There is no single value that suits every printing process, image size and viewing distance.