12/14/2023 0 Comments 0.02 print resolutione xample![]() ![]() Beyond a certain fairly definite point, which I'll cover, increasing the file size does nothing to increase output quality. The overall, practical rule is: don't go much above the minimum resolution you need, to keep file sizes manageable and avoid problems with the printer's RIP (Raster Image Processor - the software that translates you artwork to the physical dots that will hit the paper). As e100 pointed out, vectors are a Good Thing when you need to scale stuff up for grande format, but clients are clients, jobs are what they are, and we don't often get to choose. There are two answers, depending on whether you have a images (raster) or shapes (vector, including text) or a mixture of both. The related question e100 refers to has answers that also don't really cover the necessary bases. Very few, if any, grande format jobs are printed that way, and in any case, none of the answers indicated how to translate from PPI (dots) resolution in Photoshop to LPI (lines of dots at different angles) resolution in offset. Several answers refer to line screens, but technology has moved on. Grande format resolutions, as various folks have pointed out, depend on viewing distance. not downsampled to a particular output resolution. output the composite PDF from InDesign, ensuring that raster elements are output at their native resolution, i.e.compose the final artwork in InDesign, linking in the raster and vector files, adding text and simple vector elements like colour blocks.create complex vector elements like logos or illustration in Illustrator and output as EPS or PDF files.produce raster elements in Photoshop and output as TIFF files.So, again in general, your workflow would be: ![]() I never felt the need to do any interpolated upscaling of the raster images. I've certainly ended up with around 75ppi in photographic elements of 2m high event banners, which looked fine at relative distance. Certainly you should aim for as high as possible, but I don't think there's a hard-and-fast lower limit. While a PDF can contain photographic images, they will have a fixed resolution, and while 300 ppi is a good rule of thumb for publications and small posters viewed at close range, there's no way you'll achieve anything close to that at the dimensions you're talking about. This is particularly important with text and line art - visible rasterization in the finished print will be very obvious and look amateurish. Your finished print will then be limited only by the output resolution of the print device. In general you should use vector graphics in the artwork wherever practical, and deliver final artwork to the printer in PDF or other vector format. Considering that and the fact that 2x LPI is pretty conservative for reproducing fidelity (often 1.5xLPI is "enough"), this agrees with advice of 75 PPI being acceptable. That would mean your raster graphics should be about 100 PPI, or 75 PPI at 12-14 feet. (Just eyeballing the wall here.) So, by this table, you'll need 50 LPI minimum. Presumably, for a banner 3m x 5m, you'd be standing at a minimum of, say, 10 feet. The subject was black and white printing, but since colour halftone dot patterns should even be less noticeable, I think the advice can be extrapolated. So your question can be distilled down to: what is the minimum LPI halftone screen I need so that it's not distracting at the distance the poster will be viewed? I did a little searching, and actually found a research paper on this subject. Because of high-speed printing and cheaper paper/printing of newspapers, they are often as low as 85 LPI, so you can see the individual dots easily on the funny pages. Why are most things printed at 133 or 150 LPI? Because at reading distance for CMYK printing the dots aren't generally discernible. The rule of thumb is that we need 1.5 to 2 times the LPI in PPI to get acceptable results. Why? Because most raster artwork is printed with CYMK processes at a maximum (generally) of 150 LPI. for clean text resolution)" - here you're confusing DPI with PPI (often done.) Raster artwork for print is generally scanned at 300 PPI. Now you said "As i understand it 300 DPI is the typical for 'small' artworks (esp. PPI = Pixels per inch = the number of pixels per inch in screen/scanner file terms.LPI = Lines per inch = The offset printing 'lines' or dots per inch in a halftone or line screen.DPI = Dots per inch = units used to measure the resolution of a printer.Here's definitions, so we know what we're talking about. ![]() I like the accepted answer, it has good advice, but I thought I'd expand on it a bit.įor wall sized graphics and large banners (e.g 3m x 5m), what is an acceptable PPI/DPI for print. ![]()
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