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Archive for the ‘Digital Image Editing Tips’ Category
Tuesday, November 20th, 2007
Sizing digital images for various uses may be one of the most puzzling problems that the average digital photographer runs across these days. Do your eyes glaze over when trying to understand terms like resolution, pixels and dpi? Have you ever sent an image of your dog in an email that is so large that it fills up the recipient’s email in-box? Have you ever had an image enlarged and printed only to find out that the file size was too small and the printed photo is so pixilated that it looks like a graphic from an old Atari video game? If you answered yes to any of these questions then read on. Hopefully I can shed a little light on the matter.
In a previous article I provided some pointers for sizing images for email and the web. You can check out those tips by clicking HERE
Sizing images for printing is very different than sizing images for a computer screen. A concept that is difficult to wrap the mind around is the fact that the size you see an image on your screen is not the size at which it will print, unless you print at screen resolution, which generally does not have enough detail for good quality prints. For example, if I size an image to 4″ by 6″ inches at 80 dpi (dots per inch) it measures 4″x6″ on my monitor (this will be different from monitor to monitor depending on what the resolution of the monitor is set at). Screen resolution is usually between 72 and 96 dpi. At 80 dpi the 4″x6″ image looks great on my screen. When I print it, the print does indeed measure 4″x6″, but with only 80 dpi it is very blocky and pixilated. In order to get a detailed 4″x6″ print I would need to set the dpi much higher. When viewed on my 19″ screen, a 4″x6″ image at 300 dpi is too large to fit, even though it still prints as a 4″x6″ print (with much greater detail than the 4×6 @ 80 dpi). So, as you can see, how big an image appears on your screen does not necessarily indicate how large a print it will make.
Most cameras come with software that provide some help with sizing. However, this software is often oversimplified, giving the user very little control over the size and resolution of the final print. I prefer to use Photoshop, or some other advanced image editing software to size my images so that I have the most control. However, more contol also means more complexity, not something everyone wants. However you size your images, the requirements for getting good results remain the same.
Different methods of printing require different amounts of resolution detail, or dots per inch. If you don’t care that your print has jagged edges and visible pixels, then go ahead and print at 72 dpi. Some tests indicate that 150 dpi to be the minimum for good print results, but there are many factors that come in to play. For chemical process printing (non ink jet printing) 200 dpi is generally plenty of resolution. Most publishers (magazines, newspapers, etc.) have their printing standardized to 300 dpi and want all submissions at this resolution. The current generation of high quality ink jet photo printers are able to resolve detail in the 300 to 360 dpi range, although tests have shown that 240 dpi is almost indistinguishable and that 200 dpi gives great results. Knowing how the image will be printed will help you determine what dpi resolution to select when sizing the image.
Another consideration in selecting the dpi resolution at which to print has to do with the distance the print will be viewed at. Small prints that will be viewed close up benefit from higher print resolutions (240-300 dpi), while large prints that will be viewed from a few feet away can make due with lower print resolutions (150-200 dpi). Billboards that are viewed from hundreds of feet away are printed at 72 dpi and lower.
Once you know what dpi resolution you will select, the next thing to do before sizing is determine the native size of the image; in other words, the size at which it came out of the camera. In Photoshop it is easy to determine this. Open an image and then go to Image>Image Size. A dialog box will open that indicates the pixel dimensions as well as the dimensions in inches and the dpi (dots per inch). Next to the pixel dimensions it also indicates the total pixel count in thousands (k). It takes one million pixels (1000 k) to equal one megapixel. If the number in the dpi box already matches your desired print resolution, simply look at the inch measurements and they will show the height and width that the image will print. If the dpi is not correct for your desired print method, make sure that the “Resample Image” box is un-checked and then change the dpi to what you want. Once the dpi matches your desired print resolution you can now look at the image dimensions in inches to determine how large it is. For example, if you set the dpi to 200 and the dimensions in inches are 10 inches by 15 inches, the file will make a 10″x15″ print without any changes to its size. If you want to make a print that is 10″x15″ or smaller, then you are in good shape. Downsizing an image doesn’t create any resolution problems. Let’s say you want to make an 8″x12″ print. Simply re-check the “Resample Image” box, leave the dpi at 200 and then type 12 into the box that currently indicates 15 inches. If the “Constrain Proportions” box is also checked (which it should be) then the box indicating 10 inches will automatically change to 8. Click “OK” and your image will automatically be sized to print at 8″x12″ at 200 dpi. Remember not to save the image now unless you do so with a different name. Otherwise you will have permanently saved the image at the smaller size.
Now, let’s suppose that you want to enlarge the image so it prints bigger than its native size of 10″x15″ at 200 dpi. When enlarging, or upsizing, images you need to be a little more careful than when downsizing. To downsize, the software can simply remove pixels to shrink the image, which will not degrade how the smaller image appears to your eye. In order to enlarge an image, the software must add pixels. The act of removing or adding pixels is called interpolation. When interpolating an enlargement, the program uses complex math to decide how best to add pixels to make the image bigger. The current generation of interpolation software contained in Photoshop or third party applications, such as Genuine Fractals, is amazingly good at doing this. Lots of pixels can be added to enlarge an image without a noticeable decline in image quality. However, the computer can not add detail that wasn’t recorded by the camera, so at some point an enlargement will begin to show digital artifacts left by the computer doing its best to add large numbers of new pixels.
To enlarge an image in Photoshop, follow the same steps as when downsizing. Open the image in Photoshop and go to Image>Image Size. Uncheck the “Resample Image” box and enter the desired dpi resolution. This will show you how big the image will print at that dpi without any change in size. Using our previous hypothetic example, the image will print at 10″x15″ at 200 dpi. If you wish to print the image at 16″x24″ at 200 dpi, you know you will need to use interpolation to enlarge the print. As before, simply recheck the “Resample Image” box and change 10 inches to 16 inches. With the proportions constrained, the 15 inch box will automatically change to 24 inches. Click OK and Photoshop will enlarge the image accordingly.
How much can you enlarge an image and still maintain fine image detail? The answer is largely dependant on your own personal taste, the material the image is being printed on and the distance at which the image will be viewed. I have enlarged some 8×12 inch @ 300dpi images to 20×30 inches @ 300dpi with very good results, especially when viewed at normal viewing distance. The master print lab that I use has a very handy chart that helps visualize just how much various sized image files can be enlarged with good results. The chart can be viewed by clicking HERE.
So far, all of the sizing examples I have given have assumed that the image is being enlarged or reduced while maintaining the same dimensional proportions of the original. For example, an 8″x12″ image will perfectly size to 4″x6″, 10″x15″ or 12″x18″ because the proportions have not changed. However, it will not cleanly size to 5″x7″, 8″x10″ or 11″x14″ because the proportions are different. In order to size an image for printing and also crop the image to new proportions at the same time, use the Crop tool. Open an image in Photoshop and then click the Crop tool on the tools palette (or press “c” on the keyboard). With the Crop tool selected some cropping control boxes will appear below the menu tabs at the top of the page. Here you can enter your desired print dimensions and dpi resolution. If you wish to print an image at 8″x10″ at 300 dpi, simply enter those figures in the appropriate boxes. Then, move the crop tool to one corner of the image and drag to select the area that will be cropped. Once you have created the cropping area, you can use your mouse to move it around and fine tune your selection. You will notice that because you are changing the proportions of the image, some of the image will be cropped out. Once you are happy with your cropping selection, double click inside the selection or press the Return key and the image will be cropped and sized to your specifications.
Posted in Digital Image Editing Tips, Digital Photography Tips | 2 Comments »
Monday, November 19th, 2007
One of the great advantages of digital photography is the ability to easily share your photos with others. In addition to making traditional style prints, digital images can be posted on websites, uploaded to digital personal organizers, displayed on cell phones and emailed. In my business I email photos on a regular basis. I email photo submissions to publishers, proofs to commercial clients and archived image samples to stock photo buyers. But it isn’t just professional photographers who email lots of images. I also email shots of my kids to the grandparents and photos I took out skiing to my friends. Emailing digital images is most likely the number one thing that people using digital cameras do with their photos and yet many people don’t have a clue how to optimize their photos for best email performance.
The most important consideration when emailing photos is image size, especially for those of us with dial-up Internet connections, but also for those with broadband. If you set your camera to take images at a size that’s right for email then they are too small to make good prints, but if you try to email full size images they take a long time to send and don’t even fit on the screen for viewing. The solution is resizing. Most cameras these days come with software that can easily help you resize your images for email. It is also easy to resize images in image editing software such as Adobe Photoshop. However you go about sizing your photos, here are a few tips that I follow to make sure that I’m not the guy emailing photos so large that they overfill inboxes, take several hours to download and can’t be viewed without scrolling around. These tips only apply to photos that are intended to be viewed on screen but not printed. Print size files need to be large to give good print quality.
First, I like to size my photos so they are about 500 pixels on the longest side and have a resolution of 72 DPI (dots per inch). This enables them to be viewed on smaller monitors and even within the email message window without opening them full screen. 72 DPI is important because that is about the maximum resolution that a monitor can show. Images for print often need 300 DPI or more, but this is a lot of extra information that doesn’t make the image look any better on the screen. A 300 DPI image that is 500 pixels on its longest side contains 16 times more data than the same size image at 72 DPI.
Second, I save the resized images to be emailed with a different name in a separate email folder. This way I don’t change the original image file and I can safely delete the resized images from the email folder when I don’t need them any more without accidentally losing the originals.
Third, I save the email images as JPEG (.jpg) files and set the quality to medium (about 5 on the Photoshop scale) to compress the files even more. These steps ensure that I am emailing the smallest files possible and that they send quickly, don’t fill up all the space in someone’s inbox and can easily be viewed on screen.
One more tip if you are using software like Photoshop is to apply unsharp mask (Filter>Sharpen>Unsharp Mask) to the final sized image before saving and sending it. When you downsize an image it loses some detail that can be brought back with a little sharpening. Good luck and happy emailing.
Posted in Digital Image Editing Tips, Digital Photography Tips | No Comments »
Saturday, November 10th, 2007
Apparently luminosity is a term that is used incorrectly by Adobe Photoshop and photographers in general. I won’t go into the correct astronomy definition of the term. However, the inaccurate concept of luminosity as it pertains to photography is still particularly useful. In photography, luminosity is considered to be the measure of the density of luminous intensity coming from or through a surface. In other words it is an indicator of how bright a surface will appear. Because of the limited ability of film and digital sensors to capture as much tonal range of light as the human eye can, photographic images are often challenged by areas that appear to have too much luminosity (over exposure) and areas that have too little luminosity (under exposure). In a scene where the human eye can easily see color and detail on a sunlit mountainside and in the shadow of a tree at the same time, the detail and saturation in these areas of a photograph of the scene would be compromised. Luminosity masking is a masking technique in Photoshop that allows one to accurately select and adjust the luminosity of different tonal values within an image. There are many ways of working with luminosity in Photoshop, including blending different exposures of the same image, dodging and burning, screening and multiplying and using curves or levels adjustments. While all are useful in a variety of situations, they also have their limitations because of the difficulty of confining the adjustments to specific areas of an image and easily blending the adjusted area with unadjusted areas so it looks natural.
Luminosity masking makes it possible to adjust the luminosity of varying degrees of dark, light and mid tone areas in an image in a way that is gradual and completely blended. This is done by converting luminosity channels into highly detailed masks that can then be used for targeted curves adjustments. It sounds complicated, which it is to some degree. However, the power, subtlety and precision the technique provides makes learning it a worthwhile effort for the serious photographer.
The following are a links to two photographer sites that have well written tutorials on luminosity masking. Tony Kuyper’s tutorial at www.goodlight.us is particularly excellent and has an accompanying set of actions that can be downloaded. Bob Johnson’s site www.earthboundlight.com has a tutorial on luminosity masking that takes a slightly different approach towards the same goal.
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Wednesday, October 24th, 2007
In a recent discussion with a friend of mine who owns an art gallery, and is herself a photographer, she confided that she finds it much more difficult to sell photography to collectors than other types of art. I attribute this phenomenon, in part, to photography’s history as a documentary tool and, in part, to the public perception that it is a product of technology, not a skill of the body and mind. Now that cameras are ubiquitous, there may also be the impression that, while not everyone can paint or sculpt, anyone can take a photograph.
In the last decade digital technology has completely revolutionized photography, not only making it possible for more people to easily and economically shoot, print and electronically share images, but also for art photographers to access a whole range of creative tools that were previously expensive, required specialized equipment or were not even possible. And yet, the new creative possibilities seem to have only decreased photography’s artistic value in the eye of some of the public. In fact, digital photography may now fall into a new category in the public view that is separate from and, for some people, lesser than, traditional film photography.
Through my own experience and conversations with professional art photographers and gallery owners, I have noticed a perspective that troubles me. With increasing regularity, people confronted with a stunning photograph that they clearly find engaging and pleasing are compelled to ask if it is a digital image, and if so, what’s been done to it. The general perception that seems to be emerging is that film photographs are more valuable as art than digital photographs. Additionally, digital photographs that have been digitally processed in any way often are given the least artistic value despite the fact that nearly all digital images are processed to some extent either in the camera or later on. I attribute this attitude, once again, to the technology involved and the access the general public has to it. Film photography is now seen as something a bit more archaic and requiring a set of skills not readily available to just anyone, while digital photography can be done by anyone with a cell phone camera. In addition, some would think that since digital processing or enhancing an image requires even more technology, it therefore requires less skill. With the use of Photoshop, people perceive that anyone willing to spend the time on a computer can turn any digital snap shot into a work of art. I also sense that the viewing public is wary of digitally processed images because of the potential to add, remove, drastically alter or completely fabricate the content of an image. It is accepted that a painting is simply a portrayal of the artist’s vision and not necessarily reality. In many styles of abstract painting the artist is intentionally trying to get away from reality. However, people tend to want their photography to be “real”, although real is very hard to define in any visual medium.
Computer technology certainly has enhanced the ability to do all sorts of interesting things, combining components of various images, adding textures, modifying colors and even entirely and virtually generating an image. However, even though I greatly admire and appreciate this as a completely valid art form, I’m inclined to call this type of art photo illustration or digital illustration, not pure photography. The knowledge that such manipulations are possible may partly be to blame for the public’s paranoia that any visually captivating digital image must have been created in this way. However, I strongly believe that digital photography that doesn’t require these techniques is equal to traditional photography.
I would like to think that with some education, the art viewing public can learn to have a much greater appreciation for the techniques, skill, craft, creativity and mastery required to produce fine photography, whether it is film or digital. Like painters, true photography masters spend years developing their eye, style and technique and they both have the goal of creating an image that communicates an idea or emotion, defines an element of design or embodies the personal vision of a scene. Photographers, like painters, use a variety of tools and techniques to best achieve this goal. Some of these are done in the camera at the time the photo is taken, while others are performed later in the process, but all require a level of competence and ability not possessed by the unpracticed. Many photographers spend days, weeks or years waiting for the right combination of elements to come together in a photograph, and even the masters may only be able to create a few truly great photos in their career.
The public does appear to accept the darkroom processing of black and white film, even though the skill isn’t necessarily understood or properly appreciated. I have yet to hear someone ask, “how has this been altered”, or “is that what the scene really looked like” in regard to a black and white darkroom print, but these are the most common questions asked of digital photos. However, a great black and white photo wouldn’t be nearly as great without superb darkroom skills and creative techniques. Ansel Adams is an obvious and overused example, but many people don’t realize just how much time he spent working on each of his famous images in the darkroom to get them to convey his vision the way he intended. Earlier in his career he was often frustrated by the lack of skill and technology needed to create a print that matched his vision. Much later he went back and remastered many images using new techniques and improved skill. I attended a show of his work that exhibited some of his original prints side by side with the remastered ones. There was no doubt in my mind that the latter photos were better and I didn’t hear anyone complaining that the remastered images were products of technology, not a sign of his matured mastery.
  I would like to see digital processing achieve the same level of acceptance and respect as darkroom processing and for fine digital photography to rise above its “anyone with a camera could do that” reputation. I spend a lot of time carefully composing what I hope are visually captivating images, searching out exquisite light and using my knowledge of the physics of photography to get as much quality and detail from my equipment as possible. However, similar to a great black and white film print, the job is not done when I press the button. A digital sensor does not see in the way a human does, with mental filters of emotion, perception, context and experience. A raw digital image can be very flat and lifeless. Not unlike the traditional photographer, nearly every image I take requires some degree of processing using software, such as Photoshop, in my computer or “digital darkroom”. My goal is to get each image to adequately express my personal vision. Four different photographers will create four different photographs from the same location and time. This is partly due to where they decide to point the camera, but it is also due to the fact that each one of them experiences the scene differently depending on mood, perception, personality and prior experience. The digital darkroom is one of the most important tools for bringing out this individual and personal vision.
Unless I’m intentionally trying to create a photo illustration or composite, I do not alter or significantly manipulate the content of a photo. I do, however, regularly use technique and craft to adjust the contrast, correct the color, enhance or tone down saturation and vary luminosity in my images. These are very painstaking steps in the processing of an image in an attempt to bring out what I saw, felt and experienced at the time I took it. Some images require only a few seconds of my time to bring them to this state, while others I work on and struggle with for hours or days. Some images never achieve what I had hoped. Like Ansel Adams, as I learn new techniques or get better at old ones, I often go back and rework images in the hopes of making them better. My purpose is rarely to deceive or mislead (unless it is inherent in the natural composition or light), but rather to create and enlighten. The processes that I use are not a short cut and they are not an example of technology doing the work. Like a painter, or a film photographer, I use tools, as well as long practiced skills and techniques to achieve my intended final piece. Photoshop is a critical and necessary tool.
It may just be a matter of time, but my hope is that one day digital photography will be respected for the skill ,craft and mastery required to do it well in the same way that fine art film photography and other forms of art are. I look forward to a time when a digitial photo is appreciated for its content and the skill involved in creating it instead of questioned suspiciously, as if the photographer had somehow faked his ability to create something pleasing, engaging, controverial or interesting to look at and enjoy.
Posted in Digital Image Editing Tips, Photography Business, Photography Journal | No Comments »
Wednesday, September 5th, 2007
Since the beginning of human existence night sky events have inspired in us wonder, awe, inquiry, fear and superstition. Solar and lunar eclipses are particularly inspiring because they affect the largest and most important objects in the sky, the Sun and Moon. Armed with some basic knowledge they also provide us with a real-time opportunity to observe and understand the motion, relationships and interactions among the Earth, Sun and Moon. Solar eclipses (the Earth passing through the Moon’s shadow) happen less frequently than lunar eclipses (the Moon passing through the Earth’s shadow) and, due to the harmful effects of staring at the sun, are also harder to observe directly. Lunar eclipses occur about twice a year and, other than happening in the dark, are easy and safe to view. As such, they provide an excellent photography opportunity, one that can yield great documentation of a cosmological event and, with a little creative vision, compelling artistic imagery.
On August 28, 2007 a total lunar eclipse was visible from the western portion of North America. With clear skies and summer temperatures in the forecast a photographer friend, Dane (www.inner-light-images.com), and I decided to take the opportunity to try our hand at photographing the event. Even though lunar eclipses are common on a cosmic scale, they are rare enough in the course of a photographer’s career that there might only be a few chances to be in the right place at the right time to photograph one. Neither my friend nor I had photographed one before, so a little research and education was in order. There are many good sources of information on lunar eclipses on the Web. The following two links were particularly helpful in preparing to capture the eclipse on camera.
NASA’s Eclipse Info Site
The eclipse photo site of the famed “Mr. Eclipse”
A lunar eclipse only occurs during a full moon because that is when the Moon is situated directly opposite the Sun with the Earth in the middle allowing the Earth to cast its shadow on the Moon. An eclipse doesn’t occur with every full moon because the Earth casts a shadow along a plane in line with the Sun, but the Moon’s orbit only crosses some portion of that plane two to four times per year. The rest of the time the full moon is either above or below the plane of the Earth’s shadow and no eclipse occurs. Additionally, a full moon can only be seen at night due to its location opposite the sun. This means that even if an eclipse happens, you must be on the night side of the Earth to observe it. The day side of the Earth faces the Sun and faces away from the full moon, so people on the day side of the Earth during an eclipse will not be able to see it. The NASA link above provides some excellent diagrams showing how this works.
Photographing a lunar eclipse presents some challenges, but due to the slow speed and predictable nature, it is possible to prepare before hand and do a lot of trial and error while photographing one. The first challenge is being in the right place at the right time. Some enthusiasts will travel to a place on the planet where it is known an eclipse will be visible. Others, like myself, wait until an eclipse will be visible where they live. Weather is another challenge. If the sky is cloud covered the eclipse will not be visible. Many eclipses occur late in the night and getting out of bed can be a particular challenge for some. Also, a total eclipse can last up to several hours from start to finish, so some commitment and patience is required to photograph the entire thing.
Photographically speaking there are several considerations to take into account when preparing to photograph a lunar eclipse. To see the surface of the moon with a great amount of detail, a large telephoto lens is necessary. Lenses in the range of 300mm to 500mm will enlarge the moon enough for sufficient detail, but even larger lenses or small telescopes fitted for photography are needed to get a full frame image of the moon. A wider angle lens can be used with a film camera to take multiple exposures of the moon on a single piece of film. If exposures are taken every ten minutes or so, the final image will show the actual arc of the moon in intervals throughout the period of the eclipse. Most digital cameras aren’t able to take multiple exposures in one image, so to get this affect, individual exposures of the moon must be taken and then placed together in an arc in a computer using image editing software like Photoshop. For my image of the full eclipse arc I took photographs about every 10 minutes during the five hour duration of the eclipse. Then I selected 20 photos that I felt made a good sequence. In Photoshop I cut the moon out of each imaged, sized them and placed them in an arc on a black background. Then I superimposed the moon arc onto a foreground image that I took from the same location on the same night. The final image does not show the actual path of the moon in the sky, but does give a pleasing and somewhat accurate representation of the event. I chose to include the pre-dawn colors on the horizon for artistic affect even though a full moon is actually located directly opposite the rising sun.
Regardless of whether you want to take close-ups or a wide angle, multiple exposure image, you will need to be prepared to adjust the length of exposure as the eclipse progresses. A fully lit full moon is very bright and has the same exposure requirements as sunlight on rock (since that’s what it is). But, as the shadow passes over the moon and the light shifts from direct light to indirect light, the exposure times will lengthen considerably. For the completely lit full moon my exposure times were 1/400 of a second at f/5.6 with an ISO setting of 100. As the Moon passed further into the Earth’s shadow the exposure times became longer. I bracketed my exposures on almost every image to make sure that I had at least one image in which the moon was properly exposed. Eventually I reached an exposure time of one second. From calculations made before the shoot (with help from THIS website), I knew that with a 400mm lens, any exposure time longer than one second would not be fast enough to stop the Moon’s motion in the sky, resulting in a blurry image. To maintain my one second maximum exposure time I began to adjust the ISO instead of my shutter speed to offset the drop in light. In digital cameras, ISO is the measure of how sensitive the sensor is to light. Higher settings are more sensitive so they would allow me to maintain my one second exposure time, even though the Moon kept getting darker. However, higher ISO settings also introduce noise into a digital image, so I wanted to keep the ISO as low as possible to minimize noise. When the Moon was completely within the Earth’s umbral shadow (totality) my exposure was 1 second @ f/5.6 with an ISO setting of 640. Then as the Moon passed back out of the shadow I reversed what I did during the first half of the eclipse.
 Many people have asked me about the color of the Moon when it is in totality. This particular eclipse featured a beautiful brick orange/red color. The color is determined by the way light is refracted through particles and clouds in the Earth’s atmosphere as it curves around the surface of the Earth. Depending on cloud cover, pollution, fires and recent volcanic activity, the color of an eclipsed moon can vary from light orange to brick red to dark brown. The difference in brightness between the lit and shadowed portions of the Moon during partial eclipse is so great that a camera can not “see” both the dark and light side at the same time. However, the human eye can, so when we observe an eclipse we see the reddish shadow advancing across the bright face of the moon but we see detail in all areas. What a camera sees is either the red shadowed side with the light side completely white, or the light side with the shadowed side completely black. By blending two different exposures of the moon in Photoshop, I was able to create an image that shows detail in both the shadowed and lit portions of the Moon during partial eclipse, much closer to the way it would appear the human eye.
I hope you have enjoyed viewing my lunar eclipse photography and found the information on eclipses and how to photograph them helpful. My lunar eclipse photos are available as signed art prints as well as more affordable special editon poster prints. If you are interested in purchasing a signed art print or a special edition poster, please contact me HERE.
Posted in Digital Image Editing Tips, Digital Photography Tips, Photography Journal | 9 Comments »
Thursday, June 7th, 2007
One of the factors that can often make the difference between a photo being eye-popping mind candy and lackluster visual soup is the appropriate amount of contrast. Photographically speaking, contrast is the difference between the light and dark areas of an image. The less difference, the less contrast and the more difference the more contrast, one of the few things in the confusing world of photography that has a direct and logical correlation. In some images, such as foggy landscapes, low contrast is the goal. For other images, low contrast makes the image look muddy, washed out and lifeless. Depending on the nature and direction of the light source and how the light is interacting with the atmosphere, digital camera sensors naturally capture some images with less contrast and others with more contrast. Images that come out of the camera with more contrast are not usually a problem since our eyes and brains see it that way automatically. However, digital images often have too little contrast as captured by the camera. Fortunately, digital imaging software such as Photoshop gives us tools to bring low contrast images back from hazy obscurity. Below I will outline a few simple techniques to put some pop back into your low contrast images.
Open a low contrast image in the photo editing software of your choice. I use Adobe Photoshop, so my tips will be specific to that software, but most programs use very similar approaches.
Check the levels. In Photoshop, go to Image>Adjustments>Levels (or type control + L) to open the Levels dialog box. The histogram shows you the spread of color values in your image. The highlights are on the right and the shadows are on the left. If either end of the histogram doesn’t reach the end of the graph then your lights, darks or both aren’t as light or dark as they could/should be. By pulling the sliders in to meet the ends of the histogram data you will be darkening the darks and lightening the lights, which by definition will increase the contrast of your image. Hint: pulling the sliders past the end of the histogram data is generally a no-no. It will “clip” information from your image causing some areas to be completely black or completely white. Avoid this unless you are purposefully going for a Euro-fashion, impressionistic look.
   Create an “S” curve. Making Levels adjustments, as explained above, is usually a good place to begin on every image. However many images will have Levels that are already in the right range. Some images with the Levels in the correct range will still benefit from some additional contrast control. Open the Curves dialog box by going to Image>Adjustments>Curves (or type control + M). (Note: Photoshop Elements does not feature a Curves adjustment so you are stuck using just Levels.) The Curves dialog features a grid with a 45-degree diagonal line bisecting it. The lower left of the grid represents darks and the upper right represents lights. It is most often desirable to try to increase contrast without losing detail in the shadows and highlights, as discussed above. To increase shadows without losing detail, click on the diagonal line towards the lower left and drag that point down slightly. To increase the highlights without losing detail, click on the diagonal line towards the upper right and drag that point up slightly. This will create an “S” curve on the graph. Such an “S” curve increases contrast in your image. It is easy to go to far with this adjustment, so watch that itchy mouse-button finger. If you do go too far it is a simple matter to re-click each point and move it up or down until the right amount of contrast is achieved.
 
Posted in Digital Image Editing Tips | 9 Comments »
Tuesday, March 27th, 2007
As more and more people are discovering, digital photography opens the floodgates for lots and lots of picture taking. There was a time when I wanted to take more photos, but cost of film and developing, plus the hassle of dropping off, picking up and dealing with tons of prints or slides kept my shooting sporadic at best. These days I find I have the opposite problem. My camera goes along with me pretty much everywhere and I can shoot when the conditions aren’t perfect or just to experiment and have fun without concern about the cost, piles of slides building up or guilt for being wasteful. The recent explosion of very accomplished digital photographers is testimony to how many people are shooting a ton and getting good quickly.
All this prolific creativity does have its downsides, the most common being trying to manage and organize gigabytes worth of image files that are overflowing your hard drives. Without an image management system you will soon have a photo collection that is about as useful as a library in which all the book pages have been torn out and stored in a large pile in the center of the room. There are unlimited systems that could work well for indexing and organizing large quantities of image files. There isn’t one correct way to do it, just as long as you find a system that works for you and you actually put it to use.
My system is by no means perfect, but I generally make good use of my hard drive space and can find images without too much effort. Here are my top 10 tips for managing a digital photo collection.
1. Download images from your camera to your computer often. After months or years of sitting on your memory card in your camera, images are more likely to be forgotten and deleted to make more space when the card fills up. I usually download images after any photo session and then format the card so it is empty for the next photo session.
2. Initially put images in “delete and edit” folders. I have about ten numbered “delete and edit” folders into which I download images right from the camera. I know that images in these folders are awaiting processing and require my attention before they can be filed away into my larger archiving system. If I put images directly into my filing system then I forget they are there and never do any deleting or editing.
3. Be merciless about deleting images. Before moving images out of your “delete and edit” folders to your filing system, trash can any image that isn’t great, isn’t sentimental, isn’t useful or has one or more close duplicates. There is a tendency to save every single image we take. Be strong and hit the delete button on all images that won’t stand the test of time. It is also a good idea to go back through your filing system from time to time and further purge photos. You’ll save tons of memory space in the long run and you won’t have to search through so many dogs to find your winners.
4. Leave the original images unchanged and save any cropped or enhanced photos under a new name or file type. If you are going to do any enhancing to your photos, such as color adjustments, cropping or other “Photoshopping”, make sure to save the enhanced “master” version with a slightly different filename so you don’t make permanent changes to your original image. You never know when you might want to go back to the original. Way back in the day I made the mistake of downsizing a bunch of images for email and saving them as originals, not as copies. Later I wanted to make enlarged prints only to find that the shrunken images no longer had enough resolution. I also save my “master” files as .tif or .psd (Photoshop document) files that don’t further compress the image. .jpg files are good for images you are prepping for email or web because they are smaller. But each time a .jpg is saved, the image gets compressed again and loses some quality so it isn’t a good option for your “master” copy. If an original file from my camera is called IMG_4562.jpg, then I would probably save the enhanced copy as IMG_4562.tif, or IMG_4562copy.tif or IMG_4562crop.tif. I keep the same image number in the file name instead of giving it an entirely new name so I can always trace my “master” images back to their originals.
5. Use a piece of image browsing software like Bridge in Adobe Photoshop or a stand alone application like ACDsee to rank images and place them in categorized folders. Once you have done all the enhancing you’re going to do for the time being, it is time to move your images out of the “delete and edit” folders into your greater filing system so that you can find them again when you want them. Software designed for this purpose makes it fast and easy to create and name folders, move photos from folder to folder, rename photos and rank them in various ways for easy sorting and locating down the road.
6. Create a hierarchical folder filing system. Mine is based on geographical location and/or main subject matter. Dates and numbers don’t work well for me because it is difficult to pinpoint any one image to the date it was taken or to an unrelated folder number. In my system a folder path leading to a certain image might go something like this: Landscapes>Mountains>Oregon Cascades>Mt. Jefferson. Within the final Mt. Jefferson folder are…you guessed it…photos of Mt. Jefferson. In addition to “Mountains” my top level “Landscapes” folder also contains folders for Lakes, Deserts, Rivers, Valleys and so on.
7. Create as many subfolders as needed so there are never too many images in one folder. Instead of putting all 700 of my mountain photos in one huge “Mountains” folder, I break it down by mountain range and then by specific peak if necessary.
8. Use your image management software application to add keywords to your image metadata. This can be time consuming and tedious so I only recommend it if you plan on having many thousands of images in your archives. However, if you do, it can be a savior. Let’s say you have an image of a snow-covered mountain in winter. At the time you decide it fits better in the “Winter” folder instead of in the “Mountains” folder and a year later you’re pulling your hair out because you can’t find it. If you have added keywords that describe the image you can do a search for one or more of those keywords and let your computer quickly locate the image for you.
9. Use a back up system so if you have a hard drive crash all your photos are not lost. See my post on back up systems by clicking HERE.
10. For your best photos create one finished “print ready” file and then use that to size or crop for various uses. Don’t save multiple “master” versions of the same photo. It gets too confusing trying to keep track of them and it takes up memory. In a future Photo Tips feature I will explain preparing images for printing, email and other uses from your “master” in more detail.
Posted in Digital Image Editing Tips, Digital Photography Tips | No Comments »
Friday, February 2nd, 2007
One of the great advantages of digital photography is the ability to easily share your photos with others. In addition to making traditional style prints, digital images can be posted on websites, uploaded to digital personal organizers, displayed on cell phones and emailed. In my business I email photos on a regular basis. I email photo submissions to publishers, proofs to commercial clients and archived image samples to stock photo buyers. But it isn’t just professional photographers who email lots of images. I also email shots of my kids to the grandparents and photos I took out skiing to my friends. Emailing digital images is most likely the number one thing that people using digital cameras do with their photos and yet many people don’t have a clue how to optimize their photos for best email performance.
The most important consideration when emailing photos is image size, especially for those of us with dial-up Internet connections, but also for those with broadband. If you set your camera to take images at a size that’s right for email then they are too small to make good prints, but if you try to email full size images they take a long time to send and don’t even fit on the screen for viewing. The solution is resizing. Most cameras these days come with software that can easily help you resize your images for email. It is also easy to resize images in image editing software such as Adobe Photoshop. However you go about sizing your photos, here are a few tips that I follow to make sure that I’m not the guy emailing photos so large that they overfill inboxes, take several hours to download and can’t be viewed without scrolling around. These tips only apply to photos that are intended to be viewed on screen but not printed. Print size files need to be large to give good print quality.
First, I like to size my photos so they are about 500 pixels on the longest side and have a resolution of 72 DPI (dots per inch). This enables them to be viewed on smaller monitors and even within the email message window without opening them full screen. 72 DPI is important because that is about the maximum resolution that a monitor can show. Images for print often need 300 DPI or more, but this is a lot of extra information that doesn’t make the image look any better on the screen. A 300 DPI image that is 500 pixels on its longest side contains 16 times more data than the same size image at 72 DPI.
Second, I save the resized images to be emailed with a different name in a separate email folder. This way I don’t change the original image file and I can safely delete the resized images from the email folder when I don’t need them any more without accidentally losing the originals.
Third, I save the email images as JPEG (.jpg) files and set the quality to medium (about 5 on the Photoshop scale) to compress the files even more. These steps ensure that I am emailing the smallest files possible and that they send quickly, don’t fill up all the space in someone’s inbox and can easily be viewed on screen.
One more tip if you are using software like Photoshop is to apply unsharp mask (Filter>Sharpen>Unsharp Mask) to the final sized image before saving and sending it. When you downsize an image it loses some detail that can be brought back with a little sharpening. Good luck and happy emailing.
Posted in Digital Image Editing Tips, Digital Photography Tips | No Comments »
Friday, February 2nd, 2007
Have you ever had a problem trying to shoot a scene with a bright sky and dark foreground and finding that if you get the sky exposed right then the foreground is black, and if you get the foreground right then the sky is over exposed? This is especially common with sunrise and sunset photos. With film cameras the only real option is to try to balance the light in camera with split filters or holding a black card in front of part of the scene during long exposures to “hold back” some of the bright areas. Digital photography provides some new ways to achieve a balanced shot when the light range is too great. One way involves making two exposures of a scene and bringing them together in Photoshop that I call “exposure stacking”.
I employ some sort of “exposure stacking” technique in many of my landscape photos especially when the dynamic range of a scene or complexity of the skyline make use of graduated filters problematic. If you would like to try, follow these steps.
- Set up your camera on a sturdy tripod. Once you have framed your shot, lock everything down so there will be no unwanted movement.
- With the camera set to aperture priority or manual, take one shot at one to two stops above your meter reading. Now, without moving the camera, adjust the shutter speed to take another shot at one to two stops under your meter reading.
- Open both images in Photoshop and select the move tool on the tools pallet. Holding the shift key, drag the darker image on top of the lighter image. Holding the shift key will make the two images line up on top of each other.
- In the layers Pallet you will now see two layers, the light one on the bottom and the darker one on top. Make sure the top dark layer is selected and then click the “Add A Mask” button at the bottom of the layers pallet (it looks like a folder with a circle in it).
- Now select the brush tool on the tools pallet. Make sure that the foreground color on the tools pallet is set to black. With the brush opacity set to about 30% begin painting on the image mask. Everywhere you paint on the mask the top layer will be erased 30% at a time allowing the lighter bottom layer to show through. If you erase too much you can bring it back by setting the foreground color to white and painting over the erased areas to “un-erase” them.
- In this way you can bring out the lighter foreground exposure while leaving the sky appropriately exposed. It takes a little practice to get the best results and sharp edges along a light/dark boarder can be tricky, but this technique can make otherwise impossible photos possible. Give it a try!
Posted in Digital Image Editing Tips, Digital Photography Tips | 2 Comments »
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