On a long hiking trip, I used a lightweight 20MP camera to photograph a pleasant scene in a remote canyon. Later, a client orders a 60x30 inch print of the photo. What could I do in the field to get the best quality file, and how should I process the file for the best quality print?
The scene we encountered while hiking. A lightweight camera with a smallish (20MP) sensor was used to make a Panorama by merging 4 separate images. Photo: © Donald J. Rommes
There are many factors that impact the quality of very large prints.
In the field, all other variables being equal, sensor size and file quality (especially exposure and focus) are determinative.
At the other end of the process, the type of machine making the prints, and the papers and inks used, will also have an impact on the quality of the final print.
However, even using identical files from the same camera, and using the same printer with identical materials, print quality will differ depending on how the files were processed in the computer.
Let's take a few concrete examples.
A few years ago, Nancy and I were hiking in a remote section of Bears Ears National Monument. We were there on a book project, not for Iris Arts. We took our 20MP cameras because they are very small and lightweight — a better fit for our backpacks on lengthy hikes.
As so often happens, I saw a scene that appealed to me. We were in the cul-de-sac of a canyon that led to an archaeological site high on a sandstone wall. It was November. The changing leaves of the scrub oaks and canyon maples were bathed in golden reflected light.
I thought this photo had some potential as a large print for Iris Arts. Knowing the limits of my smallish sensor, I placed my camera on a tripod, exposed 4 images side-by-side, and merged them (later, in Photoshop) to make a panorama. The resulting panorama file from the 4 RAW exposures would be between 50 and 60 MP — similar to the sensor sizes of our largest full-frame cameras. The maximum print size at 300ppi from the pixels in camera's RAW file is 30 x 15 inches.
There are differences between RAW processors.
The quality and characteristics of the RAW file from the camera depend, in large part, on the software used to process it. If I used Lightroom to process the RAW files and make the panorama, I would get a different result than if I first processed the individual RAW files with Pure Raw 3 and then merged those RAW files in Lightroom.
Here are a few examples, taken from different areas of the RAW file, that illustrate the differences between two RAW processors. The differences may seem subtle in these screen shots, but they are very visible on the computer.
Figure 1. Screen shots representing 100% crops of the processed files in Lightroom. The left side was processed in Pure Raw 3 (a new RAW processor) before post-processing in Lightroom. The right side was brought into Lightroom and received identical post-processing — except for the addition of a small amount (20) of deconvolution sharpening. In our judgement, the file on the left has better detail, smoother tonality, better color transition, and less noise in the deep shadows.
Figure 2. Another section of the RAW files enlarged 100%. Same processing as described above.
Figure 3. Still another section of the RAW files enlarged 100%. Same processing as described above.
These screen shots can't show the nuances of the files, but in each example, there is a significant difference between the two. The choice of RAW processing software significantly influences the detail, noise, tonality, and color transitions of the RAW file.
There are differences in the final print depending on what software is used to process the RAW file.
As mentioned in an earlier caption, the files were then processed identically in Lightroom and later in Photoshop. The only difference was that the images on the right (the ones not processed in Pure Raw) received standard de-convolution sharpening (amount 20) in Lightroom after merging. The files on the left did not receive sharpening in Lightroom.
The choice of software used to enlarge (interpolate) the file also has a visible influence on final print quality.
When a file is enlarged, the software used to enlarge (interpolate) the file will have an impact on final print quality.
Figure 4 (below) compares two ways of processing and enlarging files. The images on the left show what can be achieved by starting from the original RAW file. In this case, a new RAW processor (Pure RAW 3) was used, and the subsequent enlargement of the file was done with Gigapixel AI.
The images on the right were prepared in the way many art consultants work — by taking the photographer's jpeg (usually at their sensor's maximum print size) and giving it to the printer to enlarge (in Photoshop) to the desired print size,
Figure 4. These are screen shots from 100% crops of the 60x30 image. The image on the left was processed in Pure Raw 3, then Lightroom, followed by Photoshop where it was enlarged in Gigapixel, then sharpened. The one on the right was processed in Lightroom and Photoshop. The full image (30x15) was saved as a jpg. That jpg was then enlarged to 60x30 using Photoshop Preserve Details 2.0 and then sharpened.
Again, these are screen shots of 100% crops of the 60x30 image. The image on the left was processed in Pure Raw 3, then Lightroom, then Photoshop, enlarged in Gigapixel, then sharpened as the last step. The one on the right was processed from the native (uncompressed) tiff in Lightroom and Photoshop and enlarged with Photoshop Preserve Details 2.0 and sharpened.
In each example, the combination of Pure Raw 3 (as a RAW processor) and Gigapixel (interpolation software) produced a noticeably better enlargement as compared to Lightroom RAW processing and Photoshop interpolation.
Using Photoshop interpolation to enlarge a jpeg to the desired size produced the poorest result.
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