Software enlargement yields greater flexibility and controllability.įor only smaller enlargements the printer driver will do just fine in my opinion. We have no influence on how this will be done and we cannot preview the enlargement. Hardware enlargement will take place inside the printer or let´s say by the printer driver (not really hardware though). When we decide to print larger than our native resolution of the digital file we can either enlarge by software or hardware. In many times you will get th best results when using even fractals of the print resolution as an input res. Most inkjet printer deliver nice images at a input resolution of around 240 to 360 ppi. This is required to compensate for dithering and the fact that many dots are required to reproduce one pixel in both color and tonality. That means they have a different resolution vertically than horizontally. 5760x1440 dpi on their consumer 13in printer R3000. Inkjet printers have different output resolutions. Billboards and posters are sometimes printed at 200ppi or less. A standard of 300ppi has been established for printing but with increased viewing distance less ppi can be tolerated. So what is the optimum output resolution of an digital file for printing? This depends basically on viewing distance and printer resolution. Adaptive interpolation algorithms try to avoid these issues by using edge detection and anti-aliasing. When using interpolation we need to watch for the following artifacts: aliasing, blurring and or edge halos. In Photoshop CC we now have the "Preserve Detail" option which is an adaptive algorithm. Adaptive interpolation is used by dedicated software solutions such as Perfect Resize by OnOne Software (formerly known as Genuine Fractals), Qimage or PhotoZoom Pro.īicubic has been the standard for most pixel based image editing software including Photohsop. sharp edges, smooth textures etc.).Įxamples for non-adaptive algorithms are: e.g. Non-adaptive interpolation treat all pixels the same way, where as adaptive interpolation are based on content (e.g. There are basically two different ways to interpolate image data: adaptive and non-adaptive interpolation. Distorting, de-demosaicing, resampling or remapping always requires interpolation of pixel data. If we want to print larger we can also add pixels and therefore deteriorate image quality in another way as we cannot create detail that is simply not there. This will more or less produce pixelation and aliasing in the final print. Printing with information at less resolution than 300ppi means we print bigger pixels created out of more dots. The more megapixel you have the less enlargement is required. Of course the closer you look at an printed image the more you see any artifacts.Īs an example a 16MP sensor will provide us an image size of 16.3" x 10.9" at 300ppi.Ī good base image quality is crucial. The standard ppi for good prints is 300ppi - however some printers and some media will work with less ppi and still produce sharp and detailed images. Inkjet printers use several small dots to recreate one pixel (dithering). When it comes to printing, dots are created by inkjet printers and that is why print resolution is measure in dots per inch (dpi). That´s simply how much information is contained inside the file. Here we talk about pixels per inch (ppi). So first we have the information provided by the digital file. This post has been inspired by our latest discussion about print size and how to optimize a digital image for printing:
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