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I have created some text art in Illustrator that I would like to print out as a poster. Whenever I save the file as a PDF (300 DPI) and print it myself the text appears crisp with no pixelation. However, I want the poster to be 18x24, which I can't do with my basic printer so when I print it I'm only printing out part of the picture, but regardless the lines are perfectly clear.

I would be fine with leaving it as a PDF, however, I've noticed most all print shops request a JPEG file for prints, which I can't figure out because based on what I've read online, JPEG files automatically reduce quality. Whenever I export the same file as a JPEG (300 PPI) the text becomes pixelated.

Is there anyway I can export this file as a JPEG and not lose quality? I've provided three images below, one is the zoomed out image, which looks fine, but the other one is a close up of the text (the letter V), which as you can see looks very pixelated.

Any help would be appreciated.

enter image description hereenter image description here

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    As long as the JPEG is at 300PPI at the correct size it shouldn't be pixelated. That being said.. Use a different printer. Requiring a JPEG for print is strange and very bad practice. It sounds like the printers either don't know what they're doing, or don't care! – Cai Feb 8 '16 at 22:32
  • I've tried with two separate printers and the JPEG came out pixelated both times. It's odd, but I've found that almost everywhere they want JPEGs (CVS, Walgreens, local print shops) and after everything I've been looking up online, really can't figure out why... – Julie Feb 8 '16 at 23:08
  • Every commercial printer I've used (whether local or online) has accepted PDF source files. The only time they complain is if I forget to "Convert Type to Outlines" (because they don't necessarily have the fonts I'm using installed on their machines). CVS and Walmart are geared to dealing with "the general public" who don't have the software or knowledge to know the nuances about file types. They constrain choices to make it easier on their staff. – Voxwoman Feb 15 '16 at 19:58
  • @julie When prepared properly, PDFs are optimal for print. However, there are many different ways of preparing PDFs, and if not done properly they can cause headaches when it comes to the pre-press stage. JPGs are basically bullet-proof, so a lot of the cheaper repro places will use them for that reason. Handling problematic PDF files requires more time and (more pointedly when talking about print kiosks within supermarkets) experienced and trained staff. – Dre Feb 19 '16 at 21:51
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Ideally you would deliver this artwork to the printer as a vector shape in a PDF. But if you have to deliver as JPEG, there are a few ways to increase quality:

1) make sure that when you export the JPEG, the quality slider is at 100%

2) set the JPEG background color to the dominant color in your artwork

3) go higher than 300 dpi — give them a 600, 1200, or 1800 dpi master

… also make sure that the size of your artwork is correct — if they are printing at 18x24, make sure your document is actually 18x24 before you export as JPEG.

  • Thanks for the responses. A few comments on your suggestions. 1) I did do this; 2) did not try this so I will next time 3) the highest illustrator would let me set the DPI was 300...Also I did create the artwork at 18x24 before exporting....something I just thought of was possibly creating the print super large (36x48) essentially doubling the size and then printing an 18x24 in hopes it would be clearer when scaled down...I've been struggling with this for days, really can't figure it out – Julie Feb 8 '16 at 23:05
  • You should be able to specify a custom resolution when exporting; it's been there since CS3 – Dre Feb 19 '16 at 21:55
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When exporting to a .jpeg, you can set your own resolution in the "JPEG options" panel. Switch 'Resolution' to 'Others' and you'll be able to type in your custom resolution.

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This artifact is called staircaising or the jaggies. It is quite annoying but impossible to avoid.

Stating the obvious: JPEG is a format designed to represent images using a matrix of pixels with parallel rows of pixels, very much like and Eth-a-Sketch toy tablet.

enter image description here

Since the rows and the columns are always perpendicular, the JPEG encoding algorithm cannot encode diagonals directly but can only imitate them by rendering ladders and selecting colours that might fool our eyes into thinking we are looking at a smooth diagonal.

The effect looks fine when looked at the right magnification and from the right distance. So when you export the JPEG at 300dpi, the algorithm assumes it will be consumed at 300dpi and does the best it can to render a smooth diagonal. If you go ahead and zoom on it then you are not consuming it at 300dpi but at a higher resolution so the artifact becomes evident.

Notice that the displays do exactly the same in order to render diagonals. We just don't notice it (anymore) because the resolution of displays is higher than what our eyes can see accurately. If you open your PDF and look at your display with a magnifier, though, you will notice the rendering algorithm of your display is using staircasing as well, even to render your crisp PDF.

So, my points are,

  • If you need to export your file as a JPEG, then you need to export it at the resolution it will be consumed.
  • Don't get flustered if you go and zoom on it and find staircases. They will always be there. The file is just not designed to be consumed at that resolution.

For printing, the general guideline is to provide images with a DPI that is 1.5x to 2 times the LPI of the press. For example, if the press is 150LPI, the images should be 300DPI. The combination of both rendering methods (JPEG and printer screens) will produce smoother results this way.

You can read the explanation for this guideline at the end of my answer to this other question.

Will increasing the dpi of my image (without re-sampling) hurt print quality?

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