It is very easy to prepare images to get outstanding prints at Turning Point Arts. In fact, it might require fewer steps than you think. I have noticed that some clients perform resizing and resampling steps that are actually unnecessary and had they not been done, very likely would have produced better prints. It would also have saved them time. So in the interests of helping you get the best possible prints with the least amount of work (on your part), I am writing this series of articles.
In the first article, let’s discuss how many pixels you need to produce an outstanding print. The number of pixels will determine how sharp or well-defined the print will appear. The number of pixels will not affect the colour reproduction, just the sharpness or definition.
Getting the best. The number of pixels you need for the sharpest results is the desired dimensions X 300 pixels per inch (ppi). E.g. for a 20″W x 16″H print, you’ll get the sharpest results with 6000 pixels x 4800 pixels. We arrive at those figures by multiplying the width (20″) and height (16″) each by 300 ppi.
To put that in perspective, you would need a 28.8 MP camera to produce a 20″W x 16″H print at 300 ppi. The Sony Alpha A850 camera comes close to this, but the majority of digital cameras in use today have far fewer pixels and they won’t necessarily achieve 300 ppi print resolution. So what do you do if you have only an 8 MP, 10 MP or 12 MP camera?
First, here’s what NOT to do. One thing you should not do is resample your image to artificially scale it up to 300 ppi (what we call up-res-ing or up-sampling). Resampling changes the number of pixels in the image file. In particular, when you up-sample an image, the software has to interpolate (invent) new pixels to produce a smooth result. There are several reasons why you should not do this. First, it is extra work on your part. Second, it will produce a much larger file which you’ll have to save and send to me. But most importantly, it won’t produce a better print. Why not?
Simply put, the software I use to print images (Qimage Ultimate) does a far better job of up-sampling than any other method I’ve seen. My own clients have confirmed this with many images that were up-sampled with Adobe Photoshop and even the highly acclaimed Perfect Resize (formerly Genuine Fractals) and other methods. In every case, Qimage produced the same or better result. Therefore, it is counterproductive for you to up-sample your image before sending it to me.
So what SHOULD you do? First, set your camera to its maximum quality setting and maximum pixel dimensions. E.g. if you have a Nikon D80 (10 MP) camera, make sure you have selected the 3872 x 2592 setting. You paid for a 10 MP camera, so why would you not want to get 10 MP images?
Second, send me your image file without resampling it. You don’t even need to resize it. Just tell me how big you want the print and I’ll produce the best possible print for you. I’ll also tell you if I have any concerns about the print quality. For example, I know from experience that a 12 MP, 10 MP or even an 8 MP camera will produce very good 20″W x 16″H prints even though the effective print resolution will be much lower than 300 ppi.
The GOOD news! With Qimage Ultimate and my Hewlett-Packard Designjet Z3100 printer at its best settings, I routinely produce amazingly good prints at only 100 ppi and in some cases, at even lower resolutions.
What happens if you don’t have 300 ppi? If an image is enlarged below 300 ppi, it will progressively lose sharpness or definition. It does not get jaggies or staircasing, it just becomes softer.
Isn’t “softer” a bad thing? That depends on the nature of the image and how the print will be displayed and viewed. Any print will appear to have a higher resolution when viewed at a greater distance. Since people tend to view large prints from a proportionately large distance, the loss of definition is actually masked by the larger size of the print. As a result, it is generally true that a large “soft” print is not nearly as bad as a small “soft” print that will be viewed close up.
Some images contain inherently soft visual elements (e.g. clouds, mist, soft focus effects, etc.). They just don’t suffer nearly as much at lower print resolutions and can be successfully enlarged further.
Besides, sometimes you just want it big, so don’t be deterred if you don’t have 300 ppi!
Next time: How best to sharpen for the print.