Have you ever seen your artwork in an exhibition catalog, magazine, or other forms of print 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) as opposed to pixels per inch (ppi). The only difference between the two is pixels are used in reference to digital applications and are square-shaped, while dots are used in offset printing and are round. ☺
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 this digital world, Low Res (72dpi) images of your artwork are the type most often used in sharing and promoting your artwork. The file size is much smaller allowing faster loading times. 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:
- blog posts
- social media
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:
- 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 the image reduce in size on your computer screen, you probably don’t see any difference if using a tablet or smartphone.
For you, it’s a few clicks of a mouse to change the resolution of the image. But for 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! 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.
Remember earlier when we touched on several pixels of color being converted to one pixel of color? This process is reversed when converting Low Res to High Res; the photo program creates additional pixels. All it can do is 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.
Most noticeable in the above example is the one bright yellow square in the upper right quadrant of the center image. Compare the same areas in the images to the left and right. See how that area of the 300 dpi image was converted from many pixels to one? 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. 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 res 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 from now on, your artwork should always appear at its best in publication, 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 to clarify converting High and Low Res images, when to use them, and why you can never go from Low Res to High Res for the reproduction of your paintings.
If you found this post helpful and would like to learn more about reproducing your artwork, there are more great posts on RGB vs. CMYK color reproduction, Getting the Color Right, and how to Capture the Best High Res Image of Your Painting.