I am learning graphic design. I know Illustrator is for vectors and Photoshop is raster images. When it is enlarged in Photoshop you can see the individual pixels and raster results. So Illustrator is widely used in Billboards nowadays. But a question comes to my mind.

I always see some edited image or photo used in the billboard. I don't understand how they can make these large images since when I make it so big it looks pixelated and rasterized in photoshop.

How is this possible?


2 Answers 2


The reason it's possible is because it doesn't have to be super great quality.

Look at this question the print DPI can be much lower on a billboard than your typical print because the viewing distance is so much father away.

For instance a 3000x3000px image at 75dpi turns out to be a 40x40in (102x102cm) image. If we switch the dpi to 10, the image becomes 300x300in (762x762cm), a huge increas, easily allowing that image to be used on a billboard.


Professional cameras

Resolution helps in this situation but not much: the Nokia Lumia 1020 has 41 megapixels and the photos are far from good. Only the use of special equipment and good illumination make an image ready to place on a billboard. This raster images are taken with professional cameras that capture every detail of the scene.

You may find plugins that convert images to high resolution minimizing the loss of detail, but the results are blurry and smudgy even when the result is high-res.

Take into consideration that when you look at a billboard you are looking from a far distance, and it is hard to detect irregularities for the human eye. It will always look good, unless you have superhuman vision.

Also, in Photoshop or any other photo retouching program you may use sharpen filters that "cheat" the human eye, making you believe that what you are seeing is a very sharp image. For example, this site has a tool that suggests how much 'sharpen' you must apply to an image based on the distance of the viewer.

  • 1
    Just as an interesting note: "20/20" (or 6/6 if you're in a metric environment) is actually pretty crappy vision; it just means that you can see what most people who can get by without eyeglasses can see. Good vision (which some people have naturally, and most people who wear corrective lenses can achieve artificially) is quite a bit sharper than 20/20. All of the "good enough" pseudo-standards we have (like 300 ppi for small prints designed to be viewed at "reading distance") are based on this "20/20" type vision, and are almost universally found wanting by people with better acuity. Sep 11, 2014 at 12:24
  • @StanRogers, I didn't know that there is a new system to measure vision beyond 20/20; but thanks for the comment, I will change 20/20 with superhuman.
    – Rosenthal
    Sep 11, 2014 at 20:17
  • I got an eye test one time and she said my vision was better than 20/20 though she didn't get me any exact numbers -- I should have asked. But that's the day I learned you can have vision better than 20/20. Hawks have 20/2 vision!
    – Hanna
    Sep 11, 2014 at 21:18
  • "20/20" just means that at a distance of 20 feet (the first 20), you see about the same as the average person does at 20 feet (the second 20). Uncorrected, my vision is about 20/200 (I can sort of make out the big "E" at the top of the chart from 20 feet about as clearly as the average person who doesn't need correction could at 200 feet); corrected, I'm more like 20/15 (which is probably getting close to the limits, and where most people would likely be if glasses and contacts weren't such a pain in the rear). Sep 12, 2014 at 0:46

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