Printing Very Large

I am currently working on getting some large prints (20x30) made for a client. Preparing images for large-size printing requires more attention to detail than small or "medium" size prints (e.g. up to 11x14). The bottom line is that small imperfections get magnified. Slightly out-of-focus images seem a lot out of focus. A tiny bit of chromatic abberation becomes a glaring green, purple, or red line. Sensor noise become much more noticeable. Although these prints will not typically be viewed up close I would rather there be as few negatives as possible to detract from the image.

Although these factors are always addressed during regular image processing, I give extra attention to these details when I prepare the images for large-size printing, making sure that a previously un-noticeable imperfection does not become a distraction. Although it is recommended to view images at 50% on screen to adjust for sharpness and other qualities I view images at 100% or more ("pixel-peeping") on-screen for this process. I inspect the image 100% to make sure I didn't miss anything. Any mistake that makes its way into printing will force me to re-print at my expense, and these large prints are not inexpensive.

Some images (to me) are just unacceptable to print very large. Of course this comes down to the judgement and vision of the artist. Some artists would print any image to any size, because the quality (e.g. sharpness) of the image is not as important as the content. But most of my images are of a scenic nature, and the expectation is that scenic images are rather clean and sharp. This will limit the candidates somewhat for large image printing. Good camera and lens technique will eliminate most of the potential problems, but some must be dealt with during post-processing.