> [Site index](https://perfectvector.com/llms.txt) — available pages and descriptions. # Actual vs Effective PPI: Check the Placed Image > Understand actual and effective PPI with measured PDF placements. Separate image pixels, source metadata, scaling, and resampling before a print handoff. Source: https://perfectvector.com/blog/actual-vs-effective-ppi Language: en Author: Irene Kim Published: 2026-10-13T08:00:00+09:00 Updated: 2026-10-13T08:00:00+09:00 **Actual PPI describes the source image's recorded resolution; effective PPI describes its pixel density at the size used in the layout.** For a placed raster, divide its pixel width by its placed width in inches. Check height separately if the image was stretched unevenly. The source's resolution label alone cannot tell you whether the placed image meets a print requirement. The same 1,200-pixel-wide image has 300 pixels per inch at 4 inches wide and 150 at 8 inches. Neither number establishes sharpness or print acceptance by itself. This guide checks an original raster inside an actual PDF. It is a file-inspection example, not an InDesign interface walkthrough or a physical print test. Keep painted artwork and photographs as raster when their tones matter; consider paths for suitable raster-only marks when editable shapes are the real need. ## Separate the three numbers | Property | What it describes | What to inspect | | -------------------- | ---------------------------------------------------------------------------- | -------------------------------------------------------------------------- | | Pixel dimensions | The raster grid, such as 1,200 × 800 pixels | The actual source and any exported/downsampled version | | Actual or source PPI | The resolution recorded for the source's native physical-size interpretation | The source file's resolution metadata | | Effective PPI | Pixels per inch at the image's placed physical size | Pixel dimensions and the size of the image content in the layout or output | PPI means pixels per inch. Printer DPI concerns output dots; a printer's DPI specification is not the placed image's pixel count. Use the units the provider requests and clarify ambiguous instructions rather than replacing one number with the other. Adobe's [CS6 printing guide](https://helpx.adobe.com/content/dam/help/en/indesign/pdf/CS6_PrintGuide.pdf) distinguishes original image resolution from resolution at the used size. That older document supports the terminology here, not instructions for a current interface. Adobe's current [printed-image resolution explanation](https://helpx.adobe.com/photoshop/desktop/crop-resize-transform/resize-adjust-resolution/printed-image-resolution.html) separates pixel dimensions from how densely those pixels occupy physical space. “Actual” does not mean that a file has been verified as detailed enough. A source can carry a high PPI label while containing a small pixel grid, compression damage, or blur. ## Calculate the density of the placed image For an ordinary unrotated placement without shear: ```text effective horizontal PPI = pixel width / placed width in inches effective vertical PPI = pixel height / placed height in inches ``` Measure the image content, not an empty frame around it. If the image extends beyond a clipping frame, do not divide its entire pixel width by the smaller visible frame width. The calculation must use matching pixels and physical extent. Uniform enlargement spreads the same pixels across more inches. Doubling both placed dimensions halves both effective PPI values. Reducing both dimensions by half doubles them. The pixel grid does not change merely because its placement changes. If you use a scale percentage, divide the source PPI by the corresponding scale factor: `200%` is a factor of `2`, not `200`. That shortcut assumes the percentage is relative to the source's native size. Using known pixels and measured inches avoids uncertainty about that baseline. ## Inspect one raster at four placements We authored a new mountain-and-sun raster at **1,200 × 800 pixels**. A four-page PDF places it at two proportional sizes, one deliberately stretched size, and a metadata-only control. Each page has the same physical dimensions. An independent inspection read the PDF's embedded image dimensions and content-stream placement matrices. It calculated the following values from the saved file, using 72 PDF points per inch with the page unit set to one: | PDF case | Embedded pixels | Placed size in inches | Effective horizontal × vertical PPI | | --------------------- | --------------- | --------------------- | ----------------------------------- | | Smaller placement | 1,200 × 800 | 4 × 2⅔ | 300 × 300 | | Larger placement | Same pixels | 8 × 5⅓ | 150 × 150 | | Nonuniform placement | Same pixels | 4 × 4 | 300 × 200 | | Metadata-only variant | Same pixels | 4 × 2⅔ | 300 × 300 | ![Actual renders of four PDF pages compare the same raster at two physical widths, a nonuniform square placement, and a metadata-only control, with measured effective PPI](https://perfectvector.com/blog/actual-vs-effective-ppi/placed-density.webp) *Actual PDF renders shown at the same page scale. Embedded pixels and placement matrices were inspected independently; the image views are not print-quality comparisons. The original raster was authored for this guide.* All four embedded image streams decoded to the same RGB pixel hash as the source. The proportional size change altered density without adding or removing pixels. The nonuniform placement also changed the artwork's proportions: its round sun became oval, and its horizontal and vertical PPI differed. The inspection's declared numeric tolerance was `0.000001` for the expected placement and density values. The example has no rotation, shear, clipping, or unusual page-unit mapping. It does not establish a general-purpose PDF preflight tool or a result in a layout application. ## Changing the source label is a different operation For the metadata control, we saved two PNG variants with nominal resolution labels of 72 and 300. Both contained the same 1,200 × 800 RGB pixels. Their encoded files differed, but their decoded pixel hashes matched; only the PNG's physical-resolution metadata chunk changed. We then placed the metadata variant at the same explicit 4-inch width. Its effective PPI remained **300 × 300**, matching the first placement. Changing a label did not improve that fixed-size image's density or add detail. A metadata change can affect a program's default physical placement when it uses that metadata. Our PDF authoring specified dimensions explicitly, so the source label did not choose the placed size. Verify how your actual application interprets the file rather than assuming every importer behaves like this example. This is why a nominal 72-PPI source is not automatically unusable for print, and a 300-PPI label is not automatically sufficient. Inspect the available pixels and the intended output size together. ## Resampling changes the pixel data Resampling adds or removes pixels to create a new raster grid. Adobe's current [Resample documentation](https://helpx.adobe.com/photoshop/desktop/crop-resize-transform/resize-adjust-resolution/resample-option-in-image-size-dialog-box.html) describes that operation separately from a resolution-label change. As a separate control, we resized our raster with Lanczos interpolation to **2,400 × 1,600 pixels**. The resulting decoded pixel hash differed from the original. It was not the same operation as changing metadata, and it was not one of the four PDF placements above. The larger grid does not prove that missing original information was recovered. An interpolated edge, a recaptured higher-detail original, and editable vector geometry are different results. Keep the source and record which operation produced a derivative. Likewise, an export can downsample placed images. The pixel count in the delivery file may therefore differ from the source you initially placed. Inspect the final output when that distinction affects the handoff. ## Treat PPI as one check in the print decision Ask the provider for the image-resolution requirement at the actual placed size, then compare that requirement with the effective PPI. Also inspect blur, compression artifacts, small features, tonal detail, and the intended viewing conditions. This article's 300 and 150 values are measured examples, not universal pass and fail thresholds. If the source does not meet the job's needs, choose a correction that addresses the cause: * **More source pixels are available:** export from the larger original or recapture the artwork with the required detail. * **The placement can be smaller:** reduce it proportionally and recalculate effective PPI. * **The artwork is stretched:** restore the intended proportions before judging its density. * **A flat mark needs editable, scalable contours:** use the original vector, redraw, or evaluate a trace of a suitable raster source. * **The texture or photographic tone is essential:** preserve the raster and resolve the source/output requirement without flattening it into paths. A fuzzy layout preview is a separate observation. Adobe's [InDesign pixelated-graphics guidance](https://helpx.adobe.com/indesign/desktop/troubleshoot/file-and-output-issues/pixelated-graphics.html) distinguishes preview settings from overscaling and low-quality sources. Read the source and output evidence before deciding which problem you have. No InDesign display setting was tested here. For appearance rather than density, the [pixelated-logo diagnosis](https://perfectvector.com/blog/pixelated-logo) covers source softness and representation. The [children's-book artwork guide](https://perfectvector.com/blog/vector-or-raster-childrens-book-illustrations) explains when painted scenes should stay raster while reusable motifs may become vector assets. ## When reconstruction is useful If the only source for a flat logo or symbol is a suitable JPG and you need editable shapes, [PerfectVector's JPG-to-SVG workflow](https://perfectvector.com/convert-jpg-to-svg) can create candidate paths for review. Compare the silhouette, corners, small gaps, and lettering with the source before using the result. Vectorization changes the representation; it does not certify the original image's missing detail or the print provider's acceptance. Use an existing native vector when one is available. For a photograph, a painted wash, or detailed texture, a better raster source or a different placement can be more appropriate than tracing. Our mountain image was authored directly and was not converted through PerfectVector. Inspect any purported vector delivery as well. A [PDF or SVG can still contain a raster image](https://perfectvector.com/blog/svg-contains-raster-image), so changing its container does not remove the density question. The [PNG-versus-SVG comparison](https://perfectvector.com/blog/png-vs-svg) covers that representation choice. ## FAQ **Can an image with 72 actual PPI have 300 effective PPI?** Yes. If enough pixels occupy a small enough physical placement, its effective density can be 300 PPI. Our nominal 72-PPI, 1,200-pixel-wide source measured 300 effective PPI at 4 inches wide. That number alone does not establish print quality. **Does changing actual PPI to 300 improve the image?** A metadata-only change does not create pixels. In our fixed-size PDF placement, the nominal 72-to-300 label change left the decoded pixels and effective PPI unchanged. Default placement can behave differently if an application uses the source metadata to choose its size. **Why do the effective PPI values differ horizontally and vertically?** The image may have been scaled by different factors in the two directions. Our 1,200 × 800 raster stretched to 4 × 4 inches measured 300 × 200 PPI and visibly changed proportions. Check the intended aspect ratio. **Is 300 effective PPI always enough?** No single density number establishes every print outcome. Follow the provider's requirement at the intended size and inspect the actual source and delivery file. Blur, compression, image type, production method, and viewing conditions still matter. ## Sources 1. [Adobe — Creative Suite 6 Printing Guide](https://helpx.adobe.com/content/dam/help/en/indesign/pdf/CS6_PrintGuide.pdf) — Defines actual and effective PPI in its image-resolution discussion; used for terminology, not current interface instructions. 2. [Adobe — Printed image resolution](https://helpx.adobe.com/photoshop/desktop/crop-resize-transform/resize-adjust-resolution/printed-image-resolution.html) — Separates pixel dimensions, physical size, density, and changes that require resampling. 3. [Adobe — Resample option](https://helpx.adobe.com/photoshop/desktop/crop-resize-transform/resize-adjust-resolution/resample-option-in-image-size-dialog-box.html) — Explains adding or removing pixels when resizing an image. 4. [Adobe — Graphics appear pixelated in InDesign](https://helpx.adobe.com/indesign/desktop/troubleshoot/file-and-output-issues/pixelated-graphics.html) — Distinguishes display-preview issues from source quality and overscaling. *** Need editable contours from a flat raster-only JPG? [Create an SVG candidate](https://perfectvector.com/convert-jpg-to-svg), compare it with the source, and verify the final placement and delivery requirements separately. ## Explore - [Read the HTML article](https://perfectvector.com/blog/actual-vs-effective-ppi) - [Sharp SVG to PNG: Size, Density, and Crisp Exports](https://perfectvector.com/blog/sharp-svg-to-png.md) - [SVGZ vs SVG: Choose a File for Editing or Delivery](https://perfectvector.com/blog/svgz-vs-svg.md) - [Product facts](https://perfectvector.com/product-facts.md) - [FAQ](https://perfectvector.com/faq.md) - [Pricing and credits](https://perfectvector.com/pricing.md)