Since we offer such a wide variety of printing technologies customers aren’t always sure what is the correct file resolution for their project. There is no single answer, I always ask:
- Describe the finished product.
- How is it being printed?
- What kind of art?”
The required resolution depends on the size of the final product is and how it will be viewed.
Both Photoshop and InDesign use PPI (pixels per inch) to describe image resolution. This is different than the resolution of a printer or other output device which is measured in DPI. “Effective PPI” in the InDesign links panel is the number you want to keep your eye on.
We have two very different mechanisms for laying down ink: digital and offset printing and large format inkjet printing. Inkjet output is a nearly continuous-tone compared to printing on an offset or digital press and that tends to push resolution requirements down.
Ideal resolution is based on viewing distance.
Offset Printing Resolution
In the world of offset printing, we’re used to holding things in our hands. 300 ppi provides excellent quality for color or grayscale images. Resolution varies inversely with the degree of enlargement – a 300 ppi TIFF placed at 200% prints at 150 ppi. Our rule of thumb for offset printing is to recommend a higher resolution photo if it dips below 200 ppi. Bitmapped line art, such as a scanned signature or a graphic with type, should be 1200 ppi to avoid jagged edges. Screen shots are an exception – they’re supposed to look a little pixelated.
If you’re printing banners, signs, or point-of-purchase displays on our large-format inkjet printers, viewing distances are often much greater and resolution can tend toward the lower end of the scale to keep file sizes manageable. The farther the viewing distance, the lower the resolution needed.
For example, if you’re working with a TIFF image size of 4928x3280px, printing at 50 dpi results in a wide format image size of 98.5″ x 65.6″.
Viewing Distance Chart
|Application||Viewing distance||Recommended Resolution|
|Printed brochures, books, posters, collateral, etc.||Up to 3 feet||300 to 200 ppi|
|Retail Window Graphics, Wall Murals, Rack Inserts/Headers||3 to 10 feet||200 to 150 ppi|
|In-Store Banners||10 to 25 feet||100 ppi|
|Outdoor Banners, Building Wraps, Car Wraps||25 feet||80 to 50 ppi|
|Billboards||More than 25 feet||30 ppi|
If you have any questions contact firstname.lastname@example.org.