Answering the High/Low Res Question

Have you ever seen your artwork in an exhibition catalog, magazine, or other print forms and been really disappointed in the quality and wondered what happened?

You made sure to send just what they asked for! Used the photo program on your computer, created an image file that met their specs — 300ppi (pixels per inch) and 1400–4000 pixels for the longest dimension. Made sure to crop your image to include ONLY the painting; no frame or other background. So why does it look so bad?

After all, the image you sent was exactly what they asked for! And, so you conclude, it must be the printer or publication. But is it? Are you sure you sent in a true High Res or high-quality image of your artwork?

Helping you to understand High and Low-Resolution image settings is the focus of this post. This is not a step-by-step how-to guide. Instead, I’ll explain the fundamentals so that you will understand the foundation of image resolution and submit the best images of your art going forward.

Oh, one quick note — I come from a print background, so by default, I refer to dots per inch (dpi) instead of pixels per inch (ppi). The only difference between the two is that pixels are used in digital applications and are square-shaped, while dots are used in offset printing. ☺

© Nancy Murty | Summer Meadow | 12×8 in | oil on linen | sold

First, let’s quickly go over a few basics, like when it’s best to use Low and High Res images and the advantages for both.

When to use a Low Res Image of Your Artwork

In today’s digital world, the most often used photos to share your paintings are Low Res (72dpi). The file size is much smaller, allowing faster loading times. In addition, being low resolution, the file does not enlarge or print well, helping to limit the unauthorized use of your image. These features make Low Res images ideal for:

  • websites
  • blog posts
  • social media
  • emails/newsletters

When to Send High Res Images

As a general rule, you should only send High Res (300dpi or better) images of your artwork when requested, and to destinations, you trust for:

  • magazines/publications
  • prints/reproductions
  • print promotional items such as postcards, business cards, posters, exhibit catalogs

Understanding the Conversion Process

Going from High Res to Low Res

It’s easy to convert a 300dpi High Res image to a 72dpi Low Res image with just a few clicks of a mouse or taps on a screen. Usually, the only change you’ll notice during the process is that the image reduces in size on your computer screen. You probably don’t see any difference if using a tablet or smartphone.

Enlarged view of the same area of a high res and low res image side by side Low res image is pixelated.
In this enlarged view of the same area, notice the square pixels in the Low Res 72dpi image.

For you, it’s a few clicks of a mouse to change the resolution of the image. But in the photo program, you’re using, its algorithm interprets the colors of multiple pixels and converts them into one pixel. Taking 300 pixels per inch down to 72 per inch. In other words, it’s converting a little over 16 pixels in a 4×4 arrangement to 1 pixel.

You Can’t Go Back from Low Res to High Res!

You may be thinking — Yes, I can! My photo program does it without any problem! But, no, it doesn’t. IT DOES NOT WORK! You cannot simply save a 72dpi Low Res image as a High Res, 300dpi image. Trust me. You can technically; the photo programs will do it, but it doesn’t work in practicality. It’s a fabricated high res image.

can't convert an image from low res to high res
A 72 dpi image is saved as a 300 dpi image. Notice how it looks blurry and out of focus.

Remember earlier when we touched on how several pixels are converted to one pixel of color? The photo edition program reverses the process in converting Low Res to High Res, except the software has to create the additional pixels. Then, it has to interpolate color from the surrounding pixels and make an approximation.

To understand this process more, we need to look at what is happening at the pixel level within the photo program’s algorithm.

Compare how the photo editing software converted the color to pixels in each image
Compare how the photo editing software converted the color to pixels in each image.

Most noticeable in the above example is the one bright yellow square in the upper right quadrant of the center image. Compare the same area in each image above — notice that multiple pixels in the 300 dpi image became one pixel in the center image? And then from one pixel to several in the image on the right. The photo program can’t create details that aren’t there in the low res (72dpi) version.

In the end, images that have been converted to High Res from Low Res often look blurry, out of focus, and distorted. In addition, the colors shift, losing the subtleties that are so important in reproducing artwork, all of which becomes evident in this side-by-side comparison.

Because I know someone is saying, “Oh, but my printer can do this.” We’re back to that; well, yes…technically, they can…but it’s still a fabricated high-resolution image. You can’t create detail that isn’t there.

I’ll repeat it. You can’t convert a Low Res file back to High Res and have it reproduce the beauty and intricacy that your artwork deserves!

Don’t feel bad if you’ve fallen prey to the simplistic seduction of the photo program’s whisper of lies. Now you know. Although I’d like to say that your artwork should always appear at its best in a publication from now on, this is only one part of the equation. Changing RGB and CMYK is another crucial component, plus starting with the very best High Res image is also essential. Hint — it’s not your phone’s camera.

I hope this helps clarify converting High and Low Res images, when to use them, and why you can never go from Low Res to High Res to reproduce your paintings.


Other Helpful Resources:

How Converting Images from RGB to CMYK Affects the Colors
Get the Best High-Res Images of Your Artwork

Video on using the color chart for photographers

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