Most readers of this blog probably think that the world-wide-web is a wonderful thing. I certainly do. Who would have predicted fifty years ago that people could gain access to an unimaginable amount of information about nearly any subject within seconds? The web does some things so well that it has changed our lives in big ways.
One thing the web generally does not do well, however, is reveal the beauty of art. How can a 300KB image on the web reveal the fineness of a large sculpture by Rodin? How can tiny images displayed on a photographer’s website compare to a real print, especially a big one?
I have a photo website and write articles for my blog. When images are posted to either one I am nearly always dismayed by their poor quality. My web images lack the emotional power of prints and sometimes do not even look like my prints.
There are many reasons for this including poor or no calibration of displays and web viewing devices such as telephones that simply lack enough display pixels to resolve important image features. One of the biggest reasons that photographs look so poor on the web, however, is that most photographers post their images with little resolution in an effort to limit unauthorized use of their work.
Images posted on my blog have only 600 pixels in their longest dimension. If a blog image is copied and then printed at the standard resolution of 300 pixels/inch, print size is limited to two inches long. Printing images with less resolution, such as 200 pixels/inch, yields larger prints (three inches long) but print quality is reduced considerably.
People recognize that most web images have pitifully low resolution but believe that poor quality is a small price to pay for quick and convenient access to images. That is reasonable.
Unfortunately, many people judge a photographer’s skill only by looking at his web images even though they are a pitifully poor representation of the photographer’s work. Evaluating a photographer’s skill requires seeing prints (or other high resolution output) and there simply is no substitute for that. Fortunately, prints and other high quality output are readily available in studios, museums and galleries and people simply need to make an effort to visit them.
To encourage readers to turn off their computers and see high quality photographs I will compare a photo posted on the web with a higher-quality version of the same photograph.
The emphasis of my comparison will be resolution. Other photograph characteristics will be ignored even though they are important aspects of image quality. For example, I often apply subtle split toning to my black and white photographs during printing but it is difficult to convey split tone effects on images that are displayed on the web.
I was driving along Colorado’s Silver Thread Scenic Byway last May when I saw trees hugging a steep mountainside. Most of the trees (99%) were in shadows and were illuminated only indirectly by blue skylight. A very small portion of some trees (1%) consisted of small branches that were illuminated by bright, direct sunlight.
Although direct sunlight illuminated only a tiny portion of some trees, it had a huge impact on mood. The bright areas created a delicate mood and helped separate foreground trees from background shadows. The small sunlit areas were the key to the photograph discussed today.
I quickly set up my 4inch x 5inch view camera and composed an image. It was important for small sunlit areas to convey a feeling of strong but delicate light. The vast majority of the scene was in shadows so I thought it also was important to obtain enough visibility in the shadows to reveal plenty of details. Consequently, I decided to place image tones fairly high on the exposure scale to preserve a feeling of light in both bright and shadowed areas.
A few light meter readings were obtained and large, dark shadow areas were placed on Zone IV (slightly darker than middle gray with good texture separation) to record plenty of detail. The foreground tree trunks also were shadowed but were brighter and fell on Zone V (middle gray). Since foreground trunks occupied much image area, I was happy that they fell on a region of the film’s exposure scale that offers maximum tonal separation (Zone V). Sunlit areas of tree branches fell on Zones VII–VIII (bright with good texture – very bright with little texture). Some of these areas were a bit bright because Zone VIII retains little texture but I thought it was okay for this photograph since the sunlit regions occupied such a small area in the photograph.
The wind was blowing moderately so I selected a shutter speed of 1/30 sec to avoid image blur. At this shutter speed Tri-X black & white film required an f-stop of f/22. I use slower shutter speeds and larger f-stop numbers for many landscape scenes but the mountainside was steep so the whole scene was compressed in a fairly narrow plane. In other words, f/22 provided enough depth-of-field to produce adequate sharpness in the photograph.
One 4inch x 5inch black & white film was exposed and marked for normal (N) development.
The film was drum scanned at my usual resolution of 5,000 pixels/inch and 16-bit pixel depth. Minor cropping during scanning produced a digital grayscale file that was 868 MB in size. During editing in PhotoShop, the foreground tree trunks were brightened from Zone V (middle gray) to about Zone VI (slightly brighter than middle gray) and the image was cropped a bit. The final flattened grayscale image was 17,402pixels x 23,385pixels and 795 MB in size.
I use the 795 MB file for printing. Printing with a standard resolution of 300 pixels/inch yields a maximum print size of 58inch x 80inch. My photography goal is to produce prints with maximum quality, however, so I usually print with an image resolution of 600 pixels/inch. Consequently, my preferred maximum print size for this image is 29inch x 40inch. Prints this size are very sharp when viewed from a long distance as well as when examined at close range with a magnifying glass.
Choosing the appropriate print size for a photograph is important and today’s photo looks considerably stronger when printed large rather than small. The image looks best to me when printed 23inch x 30inch or larger since these sizes readily reveal important visual elements of the scene that contribute greatly to its mood.
Smaller prints (e.g. 11inch x 14inch) do not work as well because small sunlit areas of the foreground trees are not revealed enough to convey the delicate mood of the scene and help separate foreground trees from background shadows. Poor separation greatly limits the sense of depth in the photograph.
Friends who have seen a large print of today’s image usually remark that the foreground trees seem to “jump out” of the background. Large prints clearly convey a strong sense of front-to-back depth and delicate sunlight.
Preparing Images For Web Display
After editing is completed and I am happy with a print, I produce image files for my photo website and blog. Obviously, files used for printing are far too large for web viewing (today’s image is 795 MB) and must be downsized severely for the web.
Images are the primary content of my photo website whereas text is emphasized on my blog so slightly higher resolution images are displayed on the photo website than on the blog. The longest image dimension for my photo website is set to 750 pixels whereas the longest dimension for blog photos is 600 pixels. Readers of my blog may recall that I frequently encourage visits to my photo website to view slightly better versions of photographs discussed in the blog.
To appreciate the severity of downsizing images for the web, let’s consider downsizing today’s full resolution image (17,402pixels x 23,385pixels) for display on my blog (447pixels x 600 pixels). The 17,402 x 23,385 image contains a total of 406,945,770 pixels whereas the 447 x 600 image for the blog contains only 268,200 pixels. The number of pixels in the blog image is only 0.06% of the number in the full resolution image. Put another way, the number of pixels in the full resolution image is reduced by 99.94% to produce an image for the web. This is severe downsizing indeed.
How much detail in the original photograph is preserved in a web image? How strongly will the photograph’s mood be conveyed in a web image? The answers to these questions vary for different images but it is clear that a typical web image is quite different than an original print made from the full resolution image.
Comparing A Web Image To A Higher Quality Image
The 447pixel x 600pixel image that was prepared for the web is shown below. Personally, I see little value in the web image because it looks tonally flat, spatially flat, lifeless and boring. Most important, the presence of direct sunlight in the image is not visible. In contrast to this, I consider a large print which is made from the original high-resolution digital file to be one of my finest photographs because it exhibits substantial depth, conveys a beautiful mood of delicate light and is visually exciting. How is that possible?
I will attempt to communicate specific image features that result in some of the differences between the web image and a large print by discussing one small image area. The area includes the center tree trunk in the foreground slightly below the photograph’s centerline. This area has a fairly large branch that curves left and downward.
In the web image, the selected area covers a 69pixel x 100pixel region of the whole 447pixel x 600pixel image. The 69pixel x 100pixel area was resized to 417pixels x 600pixels to reveal its contents better and make comparison to other images easier. The resized area selected from the web image is shown below.
A similar area was selected from the 17,402pixel x 23,385pixel full resolution image. It covers nearly the same image area as the web selection but includes 2,432pixels x 3,546pixels in the full-resolution image. Since the size of the selected area is nearly 9 MB and is too large for easy web display, the selected area was resized to 411pixels x 600pixels.
Note that we actually are not comparing the web image to the full resolution image since the number of pixels in the selected area of the full resolution image was reduced for display here (2,432pixel x 3,546pixel selection reduced to 411pixels x 600pixels). A more proper comparison would involve side-by-side comparison of the 69pixel x 100pixel selection from the web image and the 2,432pixel x 3,546pixel selection from the full resolution image but the latter selection is too large to display on the web.
Nevertheless, useful conclusions can be obtained from the more modest comparison shown here. Just remember that the full resolution image will display considerably more detail than seen here.
The high resolution area after downsizing is shown below. Five numbers were added to the image to facilitate locating specific details for discussion.
The poor quality of the web image compared to the higher resolution image is evident when the previous two images are compared. The resolution difference is clear even though the full resolution selection was downsized by reducing its number of pixels by more than 97% (2,432pixels x 3,546pixels were downsized to 411pixels x 600pixels). Again, remember that a large print which displays the full resolution of the photograph will contain substantially more image detail than seen here.
Number 1: This number draws attention to a bright line on the left side of the tree trunk. This vertical line is produced by direct sunlight and is important because it helps visually separate the foreground trees from background plants. Visual separation helps communicate front-to-back depth in the photograph. The narrow line of bright light also contributes to the photograph’s mood by adding delicacy and luminosity. The web image shows little or none of this line so it appears flat and shows little of the delicate and luminous mood that the higher resolution image exhibits.
Number 2: This number draws attention to a bright band of direct sunlight on top of a curved branch immediately below the “2”. The narrow curved line adds depth, delicacy and luminosity to the higher resolution image. The line is totally absent in the web image and the absence of features such as this results in a lack of depth, delicacy and luminosity.
Number 3: This number is located near groups of needles from conifer trees that are located behind the foreground trees. Needle groups are not strongly visible in the higher resolution image shown here but individual needles are plainly visible in a full-resolution print. Needle groups can’t even be detected in the web image. Since needles are located behind the foreground trees, their presence in the higher resolution image helps communicate front-to-back depth at the scene. Their absence in the web image contributes to a flat image.
Number 4: A leaf group and stem are visible above the “4”. Its structure can be seen easily in the higher resolution image but few of its structural components can be recognized in the web image. Since most of the leaf groups are located in front of the foreground tree trunk, their presence helps communicate front-to-back depth in the higher resolution image. Poorly defined leaf groups in the web image contribute little to image image depth.
Number 5: Dark, jagged lines can be seen on the tree trunk to the left of the “5”. These lines give shape to the trunks and help distinguish foreground trees from the background trees. The lines help communicate front-to-back depth in the photograph and help the foreground trees “jump out” of the background. The dark lines can barely be detected in the web image so it appears to be flatter and possess less front-to-back depth than the higher resolution image.
Most images displayed on the web have remarkably poor quality. Many web images simply can not communicate important structural features or the mood of photographs and bear little resemblance to their high resolution counterparts.
An image was discussed today which contained fine features that are essential to the mood of the photograph. The downsized image prepared for web display can not reveal the fine features and the web image simply can not communicate the delicate mood and depth of the original photograph.
Even though most of us view web images frequently because they are readily accessible, we should recognize limitations of the web. In particular, we should withhold important conclusions about artistic merit until higher resolution output is seen. For many photographers, that means looking at prints.
There is no substitute for seeing the real thing. Visit an art gallery, museum or studio today!
Randall R Bresee