Photographing for web pages

A snapshot is what happens when you point a camera at something or someone and press the button. Given that there is sufficient light and the subject is within the focusing range of the camera, something will be recorded on the film. What has happened is that an event in space and time has been captured and frozen for posterity.

A photograph, on the other hand, has to be worked at. You have to compose the picture, get the exposure and shutter speed right and hopefully make some sort of statement other than 'this is what was in front of the camera when the shutter clicked!'

Most photographs on Web pages are just illustrations rather than 'statements of self expression' but it is reasonable to expect a certain degree of competence nevertheless. The medium is fairly undemanding because of its low resolution. A picture that would be unacceptable for print reproduction can usually get by in the form of a small Web image and, with a little bit of tweaking in an image editing program, serve its purpose admirably. A little colour correction here, a little sharpening there, make it into a JPEG and that's it!

Well, not every picture is rescueable with Photoshop, nor deserves to be, but there are some things you can do to improve your Web page photographs before you even get that far.

Don't use flash! It's funny, one of the biggest boons to modern photography is also its biggest problem – the built-in flash. Nothing kills a picture more than the flat lighting, hard shadows and glowing red-eyes produced by on-camera flashguns. Right beside the lens is the worst possible position for a light source yet millions of such snapshots are 'committed' every day. Yes, it's convenient. Yes, it's easy. But if you want a decent picture and it's not an absolute emergency, switch the flash off and find a more sympathetic natural light source.

The two basic problems with on-camera flash units are, their proximity to the lens and their point-source nature. Being so close to the lens means that the lighting is flat with no modelling. Any shadows that would help to define shape and texture are directly behind the subject and hidden. The small size of the light source means that any shadows that are visible have unflattering, high contrast, hard edges.

It is unusual for digital cameras to have flash synchronisation sockets, so you can't even attach an external flashgun.

Most good flashguns have swivelling heads that can be twisted to point at the ceiling. Bouncing flash like this gives a more natural looking illumination with soft shadows. On-camera flashes don't usually allow this kind of situation but a 3-inch square piece of white paper or silver foil can be fixed in front of the flash at 45° to reflect some light upwards towards the ceiling. The light that passes through white paper gets diffused and softened, silver foil directs more light upwards. Provided your camera is capable of compensating for the reduced intensity of the light, and you might have to go into 'manual mode', the resulting picture should be much better.

Another way is to buy a flash 'slave' unit. This is a light sensor that is either built-in to some flash guns or can be a small external device that connects to the external flashgun with a cable. Essentially, it is a 'magic eye' that detects when one flash goes off – the one on the camera – and fires-off an external flash, which can be more appropriately situated. The trick here is to use some paper or foil to obscure direct light from the on-camera flash onto the slave unit but not the subject.

Getting away from flashes completely, a video light gives constant light and doesn't need to synchronise with the camera at all. A small battery-powered video light with a reflector or diffuser gives much more control over the light and shadow quality. It can be placed well away from the camera on a stand or held by an assistant and eliminates all of the problems associated with on-camera flashguns.

Remember, good photography is about the quality of the lighting, not the quantity.


Flatbed scanners, digital cameras, etc.

The most common way of turning a photograph into a Web image file is to scan a print with an ordinary flatbed scanner. Scanners have come down in price quite significantly in the last year or so and even the cheapest ones can give a reasonable, if not great, image quality. Prints suffer from a number of problems. Send the same negative to two different labs and you will get quite different prints, or even to the same lab on separate days. Commercial prints are put through a kind of sausage machine, they are never good at the best of times. All you can expect is that they are 'acceptable' for their purpose. Scanning such prints with a low-cost scanner is also going to push the boundaries of acceptability. Not only do you have the low contrast and paper surface texture to contend with, the scanner itself is probably not calibrated properly and you are introducing yet another layer of errors.
If your scanner has adjustment facilities in its scanning software, it is always better to make serious colour and contrast corrections before scanning and leave the image editor to do fine-tuning. Correct any serious colour cast first before adjusting the contrast otherwise you will just make the wrong colours stronger.

The idea is to capture the maximum possible amount of information in the picture file because the process of image editing inevitably throws information away, and you can't bring it back.

After scanning the print at about twice the required final size, fine adjust the colour balance and tonal levels. Most pictures have areas of black and white in them, though not always. As a general rule, you should use the 'levels' control to set the darkest point of the picture to black and the lightest point to white. You can do this with the sliders or with the dark and light eyedropper tools.

The tonal graph should, ideally, span the total width of the 'levels' window but here it is falling short at both the high and low ends (left and right). Moving the pointers inwards (red) to match the darkest and lightest parts of the image (the pale yellow area) increases its contrast just like turning up the bass and treble on a hi-fi system. The middle arrow can be moved towards the left (green) to 'open up' mid-tones that are too dark.

Unfortunately, this process does not introduce new information, you don't get anything for nothing, it just stretches what's there is to fit. For best results, the scanner should be adjusted to make sure it captures the full tonal range from the outset. You will have to check your scanner software manual for instructions how to do that.

When the image looks right, and you have removed any blemishes, reduce it down to its final size. If you reduce the image any more than about 50%, you might need to apply a small degree of sharpening, or 'unsharp masking', which is more controllable and not so severe. Over-sharpened images look just as bad, or even worse, than soft ones. If your subject is a face, for instance, try just sharpening the eyes. It is amazing how a crisp highlight in the eyes can seem to bring a blurred portrait into focus.
Note: If the full version of Adobe Photoshop is too expensive for you, Adobe Photoshop Elements gives you most of the facilities of the full version for a fraction of the price and I highly recommend it.

Some of the problems associated with scanned prints can be sidestepped by scanning transparencies or even negatives. Some flatbed scanners have transparency adapters but these are usually hopelessly inadequate for small film formats like 35mm or APS, even for the relatively low demands of a Web page image.

Dedicated film scanners give the best possible file quality, and this is what professionals use. A transparency (or even a negative) contains a greater amount of detail and contrast. Where prints are always viewed by reflected light, and much of the available light is lost by scattering and absorption, the light passing through a piece of film remains relatively unscathed. The contrast ratio, the difference between the lightest and darkest parts of the image, is always much better in transmitted light.

Professional film scanners used for print work are extremely expensive but there are 'desktop' models that are more affordable and produce superior image quality to their flatbed counterparts.

The only thing to watch out for with film scanners is dust and dirt. The smallest hair will magnify to horrendous proportions and it's considerably easier to remove it with a puffer brush before scanning than to have to do it in Photoshop afterwards.

Don't be tempted to scan at too high a resolution with any kind of scanner. Reducing the image always has a softening effect. If you do have to reduce an image by a significant amount, do it in stages – 50% at a time – applying a small amount of unsharp masking at each step rather than trying to do it all at once at the end.

Like scanners, digital cameras are becoming more affordable although they still cost more than much more capable 35mm cameras. For Web pictures, just about any digital camera will do. You don't need very high resolution but the more expensive high resolution cameras do tend to be better in other areas too – colour accuracy, zoom lenses, macro facilities etc. Get the best one you can afford but don't plan on keeping it too long because you will probably want a new one in a year's time, one that is even better and probably only half the price.

When you have the image you want on your screen, the final process is to reduce the file size for transmission over the internet without compromising its quality. This invariably means saving it in JPEG format (.jpg). JPEG is a 'lossy' format that allows you to trade-off file size against image quality. Compress the image too much and it will have all kinds of nasty blemishes. You can only do this visually, there is no magic formula.

I like to reduce the compression setting to the point where the compression artefacts just start to appear and then back-off a little. This 'threshold' point varies considerably with the type of image from about 35% to 65%. Busy images with lots of texture can withstand higher compression than ones with areas of flat colour and well defined edges.
In the end, photographic quality is subjective. If you have a picture of a flying saucer hovering over the Whitehouse, the quality should be poor to be believable - and hide the wires. At most other times, it should be as good as you can possibly get it.


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