BOOT CAMP 202 (13-20/11/01)

PICTURE EDITING part 3

Having dealt with the fundamentals of picture editing in parts 1 and 2 we are now ready to move on to some more advanced digital image trickery. I’ve chosen two fairly common jobs – eliminating red-eye and removing a person or object from a picture. Between them they involve a range of relatively simple techniques that can be readily adapted to a wide variety of picture editing jobs and the tools required are common to most picture editing programs, including the sometimes fairly basic ones supplied with digital still cameras.

If your program doesn’t have the facilities mentioned I strongly suggest that you get hold of one that does; photo editors worth considering include, Adobe Photoshop Elements, JASC PaintShop Pro MGI PhotoSuite, Serif PhotoPlus and Ulead PhotoImpact

Red eye is caused by light from a flashgun reflecting straight back to the camera from a subject’s eyes; blood vessels in the retina produce the characteristic red colour, which gives the subject a somewhat demonic appearance. Compact cameras are the worst offenders because the flashgun is usually very close to the lens. (Trivia note: photographs of cats and dogs often suffer from ‘green eye’, that’s caused by a structure in the animal’s eye called the ‘Tapetum Lucidum’, which assists night vision…).

Several picture editing programs have automated red-eye removal facilities, and some of them are quite good, but it’s actually very easy to do it manually, and it will help you to become more familiar with some important features in your software.

Open your picture-editing program and display the image you want to work on. Get into the habit of using Save As on the program’s File menu to rename and save the image straight away, so the original is preserved, just in case you make a mess of it...

Use the magnification tool to zoom in close on one of the red eyes. Now change to the freehand selection tool and carefully outline the red area of the eye. You could of course simply ‘fill’ or change the colour of the red area but that would look very odd – more so than red eye in fact. The trick is to remove the colour – i.e. turn the defined area black and white -- using the program’s colour or saturation controls. This means that the texture of the image is retained and the end result will look perfectly natural. When you’ve removed the colour zoom back out to normal size and if you’re happy with it save the image and repeat the process for all other affected eyes.

Removing people, objects or things apparently growing out of people’s heads etc., from photographs is another reasonably straightforward job, in principle at any rate, but it’s easier on some photographs than others. The determining factor is the background, and what’s behind the person or object you want to remove. The idea is to replace the object or person with sections of background taken from other parts of the image, preferably close to the object, so you get the best match in terms of colour, brightness and scale. The best backgrounds are either plain or blurry  – the sky or the sea for example – or tightly textured or patterned with a uniform colour – grass, bricks, leaves on trees etc. Images with irregular background, buildings, large shapes and lots of colour or perspective etc. can be more difficult to work with.

There are various ways of doing it but the simplest method, and the one that’s applicable to most picture editing programs, is to use a combination of copy and paste – to mask out the object -- and the ‘clone brush’ tool to tackle fine detail, tidy up edges and spot out imperfections.

As usual start by opening the photograph and use Save As to create your working copy and remember to save your work every few minutes. There’s no right or wrong way to proceed but I usually find it easier to enlarge or zoom in on the image and work on only a small area at a time. Use the freehand selection tool to define smallish chunks of background adjoining the object then copy and paste or ‘float’ the sections over the object to mask it out in several operations. The size of the chunks depend on the uniformity of the background and larger areas are more difficult to work with, and can look awkward as they may contain graduations in brightness and colour, shadows or fine details that show up as a repeat pattern, or a defined edge. If available use the ‘feather edge’ option as this will makes the edges less distinct. Return the image to normal magnification and check your progress every so often.

When the bulk of the object or person has been obliterated you can use the clone tool to obscure edges and edit fiddly details. You will probably find it easier to work at even higher magnification levels, so you can start seeing the individual pixels. it’s more accurate and the results will look a lot better. The clone tool is one of the most useful facilities in an image-editing program. It ‘picks up’ detail and texture from a selected part of the image and the brush tool ‘paints’ it back into the picture. It takes a little practice to become proficient with it and you will probably have to experiment with the brush size and shape options but once you’ve got the hang of you will find that you can do some amazing tricks.

Next week – Introduction to video editing

JARGON FILTER

FLOAT

A drawing tool or option that lets you copy and move a defined area of a image to another part of the picture

FREEHAND SELECTION TOOL

Drawing tool that lets you define irregular shapes by moving the mouse cursor – usually display as a set of crosshairs – around an object whilst holding down the left mouse button

PIXELS

Picture elements, the individual building blocks that go to make up a digital image

TOP TIP

Whilst it’s easy enough to remove red-eye in a digital image, it makes sense to avoid it happening in the first place. You can’t do much about the position of the flashgun on most compact cameras but a lot of models nowadays have a red-eye reduction mode. This is usually a bright light or weak ‘pre-flash’ before the main flash that reduces the size of the subject’s pupils. If your camera hasn’t got this facility you could try asking the subject to look at a bright light, just before you take the picture. Alternatively try covering the flashgun with a paper tissue or handkerchief, which has the effect of diffusing the flash.