Text and images Copyright Mark Graf, 2004. All rights reserved.
Dogma - n. A principle, belief, or statement of idea or opinion, esp. one authoritatively considered to be an absolute truth.
Dogmas have been around for many, many years regarding print size vs. the size of your original format, whether it be 35 mm film or a digital file. Some claim the maximum size a sharp 35 mm slide, low ISO film can be enlarged and still retain quality is somewhere between 11x14 and 16x20 inches. Others divide a digital camera's largest pixel dimension by the 'standard' 300 dpi and come up with a maximum possible print size. "Maximum possible" can be a very deceiving term in itself, because the quality of an enlarged image is very subjective. Very large prints aren't typically viewed from 3 inches away, though we photographers like to do so as the ultimate judgment of quality. Are we strictly limited by the quantity of pixels coming out of the camera? The opinions regarding this subject are endless. You might even find some that are speaking to print sizes they have never enlarged to for themselves.
Advances in imaging technology have drastically changed those old dogmas for many, including myself. However, time and time again you see questions asking how big of a print can I make - and a myriad of responses from both ends of the spectrum. I am not about to add another restriction based on my own beliefs either, because I am constantly amazed at some of the beautiful prints I see from rather humble beginnings. So I have fallen back on the old saying "Seeing is believing," and the only way you will ever have the question answered is to try it for yourself.
I have certainly done this with my 35 mm slide scans, where I will not even hesitate to make a 16x24 print from a sharp original and a good 4000 dpi scan. I am sure I could go larger, many photographers commonly do so. When I dove into the sea of digital SLRs, I was again challenged with the same questions. Research yielded the same range of opinions and responses. So I decided to try it for myself with one of the first images from my first digital SLR, the Nikon D2H.
This is a 4.1 MP camera (quite low by current standards), which had its share of complaints from those expecting higher resolution. If I were to limit myself by dividing those pixels with a 300 dpi print standard, the maximum print size I could obtain would be around 5x8 inches. I needed to know for certain as I do offer prints for sale from these images and wouldn't want my customers to have anything I wouldn't hang in a gallery or my own walls. I also needed files of minimum 50 MB for uploading and acceptance by my stock agency (accomplished through interpolation). Plain and simple...Seeing is believing.
Below are some images of a print I had done as a first test, the print shop did the up sizing for me. The image started as a RAW camera file, processed using Nikon Capture 4.0, and saved as a JPEG at the highest quality setting. The resulting 2.7 MB JPEG (yes, only 2.7 MB!!) was then uploaded to the print shop.
The print size is 24x36 inches, and I was very uncertain about how it would turn out.
Below are some shots of the print and are not altered in any way different than my typical prep for web display. These web presentation images, photographs of the ACTUAL PRINT, the photographs of the print itself were shot as fine JPEGs, straight from the D2H camera, ISO200, resized to 72 dpi, converted to sRGB colorspace, and one application of USM at 500%, R0.1, T0 simply to correct for digital capture.
I was shocked - the print was very sharp, no evidence at all of seeing pixels or jagged lines, even upon very close inspection. Fur detail was excellent, right down to the whiskers. I was very pleased. In fact, so pleased that I wanted to share the results here. Below are some closer shots. These images are photographs of the actual print. Colors may be slightly shifted from the above image since I used fill flash to compensate for the strong backlighting outdoors. Flash was not used on the close ups to avoid glare.
Nikon D2H, 17-35 mm lens at about 12 inches from print, ISO200
Nikon D2H, 105 f2.8 Macro lens, ISO 200
Only with a macro lens on the tiger's eye was I able to see some hints of 'grain', more likely digital noise, which disappears if you are at 12 inches away. This is still ridiculously close for viewing a 24x36 inch print., Regardless, I still wanted to present what it looked like for those that do want that closer view.
I have concluded that my first test was a complete success, and will definitely be trying enlargements of this magnitude with different subject matter and situations. This tiger image was tack sharp and well exposed to begin with, which would seem to be prerequisites for obtaining similar results. I will also say that I have sold as stock many images from this camera that were interpolated up to the 50 MB standard minimum file size - again no issues.
I certainly don't want to give the impression that making routine enlargements of this magnitude is a trivial task. It can also depend on your subject matter. Single subjects may enlarge a bit better than highly detailed landscapes. I certainly retained a lot of fine detail in the whiskers and face of this tiger. Common sense also dictates that noisy images are going to give you some problems, exposure must be good, captures from DSLRs are going to generally provide a higher quality file than a point & shoot due to the larger sensor sizes. Not all megapixels are created equal!
So, how do you try this for yourself? There are many software tools available now that help with interpolation up to the largest print sizes. This tiger image was enlarged using Genuine Fractals by the lab I sent it to, although I now use a combination of either Alien Skin's Blow Up or tools within Photoshop - depending on which one gives the best results. The Fine Art Printing: Camera to Print video tutorial linked below offers excellent advice on resizing and getting the best possible prints. If you can print at home, but only to a certain size - use one of these software tools to enlarge the image - then crop out a small section and print it up to the size your printer can do. It will give you a good idea of the quality before sending the file off to a lab.
I can only recommend for those plagued by the dogmas of resolutions and print sizes to try this for yourself. Find a lab that has done this for many of their customers. Don't be afraid to push the limits. You may be as surprised as I was.