As we have seen in the previous posts, many factors affect print quality. Understanding those factors can help in choosing an image for a very large print — especially when the highest quality is important.
Drying mud, Moqui Canyon. Photo: © Donald J. Rommes
The subject of a photograph often trumps its quality. There are other situations where print quality is not the first priority — on a billboard for example, or on a wall removed from the viewer. Print quality may not be important to the art consultant when it's not important to the client.
However, when optimal print quality is desired, what should art consultants consider when choosing images for very large prints?
Know what a good print looks like.
Knowledge of what a good print should look like is probably more common in art consultants than most viewers, but it is not a given. There is wide variation in the educational background of art consultants and not everyone has an expertise in the fine art photographic print. Obviously, quality standards will vary with expertise. There is not always a need for high quality prints, but it is nice to know quality when you see it. It will help you distinguish between your photographers and your printers.
Camera sensor size.
As we have discussed in previous posts, sensor size is an important factor in determining how big a quality print can be made from the image file. For any desired image quality, the larger the camera sensor size (resolution) the bigger the print can be. Of course, the resolution of the image sensor used to make the exposure is not usually visible to the consultant. But you can ask the photographer.
File size.
Image file size can be proxy for the sensor size. In other words, a larger jpeg or tiff file usually means a higher sensor to start with, but not always. There is no way to know, for instance, if a given file has already been enlarged from a smaller sensor. Again, ask the photographer if this is an important consideration.
Processing details.
In previous posts, we have shown that decisions about processing the RAW file and enlarging (interpolation) in Photoshop will have an effect on file quality and, ultimately, print quality. While it is probably unrealistic to ask your printer or photographer about the various software and techniques they used in processing, art consultants should at least be aware that software choices and processing capabilities vary between different printers and photographers. These differences have an impact on the appearance of final print as illustrated by the previous post.
Craft is still very important in photographic art.
Starting point.
As we have said elsewhere in these posts, our website files are in jpeg format because that is what most of our clients want. Those jpegs were created after our RAW image files were processed to their maximum native file size at 300ppi. For example, a jpeg from one of our 42MP camera sensors would make a print that is about 27x18. But if a client wanted a 60x40 (4 times the area), the jpeg would have to be enlarged considerably.
If a smaller sensor was used as a starting point for our website file — say 24MP — the resulting jpeg would have to be enlarged even more to produce a 60x40 print.
If your printer used a jpeg as a starting point to make a large print, the result would never be quite as good as the one he could get by starting with the original RAW file or uncompressed tiff. That quality difference is exaggerated when starting with a file from a smaller sensor size and wanting a bigger print size.
Most photographers will not surrender their RAW files, so they are the only ones to generate files from them. A tiff file will produce excellent results when enlarged — not quite as good as from the original RAW file — but the differences are more subtle. But your printer will have to do the work of enlarging the tiff file (possibly with selective noise reduction and sharpening) before printing. Therefore, if your photographer's skill in processing is as good or better than your printer's, you will get the better file from the photographer who can go back to the RAW file if needed.
The worst quality comes from using small jpegs as starting points for very big enlargements. That's because you are starting with a compressed file where most of the pixels have been discarded and have to be re-created.
Quality Considerations.
Not every photograph needs to be printed at the highest quality. The requirements will vary with the demands of the client, the budget, and the placement of the print.
For those situations where print quality is important, having an understanding of those factors influencing quality will not only inform your choice of photographs, but also your choice of printers and photographers.
Ultimately though, the proof is in the pudding. Look at the results, consider test prints if in doubt, and quite soon you'll develop confidence in your photographers and printers.
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