The Red Eye Problem PHOTOGRAPHY & IMAGE PROCESSING - THE RED EYE PROBLEM

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1 The Red Eye Problem This lesson will explain what red eye actually is and show some techniques on how to prevent it happening. It also includes a demonstration of how to remove red eye in Post Production. Nick Kind course@nickkind.com

2 What is Red Eye? Red eye is basically the direct reflection of light from a camera s flash hitting our eyes and then bouncing back through the camera lens. The light is reflected by our eyes which act like a mirror making them appear very bright and red in the photograph. The reason for the color red is simple. When the flash from the camera hits our eyes it penetrates and is reflected back from the retina. The color is red because the light is actually reflected from the blood in the retina. It only occurs when using flash photography and because we are usually in a darker environment where the subjects pupils are more likely to be larger. This of course increases the problem. It also explains why some people get red eye more than others as sizes of pupils vary. The problem is accentuated by the camera lens and flash unit being very close together. This is typical on most compact digital cameras as it s impossible to get any real distance between them. Therefore the angle of the flash reflection is very small which means it s likely to score a direct hit through the lens.

3 Reducing Red Eye using your Camera The most obvious solution is to use your Red Eye Reduction function on the camera. This fires a few pre-flashes before the final flash which causes the size of the subjects pupils to contract. Thus when the last flash hits and the picture is taken, there should be less chance of a reflection. This is quite a successful method but it can result in people blinking as the pre flashes either cause them to blink, or they may think the first flashes were the actual shot. Try and see if you can get as much light into the room as you can. For example switching the lights on will help keep pupils smaller and reduce the chance of reflection. Another simple solution is to get the subject to look at the camera, but not directly into the lens. Perhaps to look at your shoulder or the top of your head. This helps increase the angle of light reflection. Some cameras will let you control the power of the flash. By reducing the amount of brightness you reduce the chance of red eye. But you do run the risk of a darker image. If your camera doesn t support this feature then you could try and reduce the brightness manually. Sticking over a piece os tissue paper will diffuse the light nicely. It might be tricky to do, but it does have a very good effect. If it s at all possible, try and increase the distance between the flash unit and the camera lens. This of course is impossible on a compact, but with a digital SLR camera you can buy separate flash units that will do just that. You can even hold the flash in your hand or put them at various places and work them by remote control. With these flash units you will also be able to angle the flash. This is called bouncing. Sometimes the best effect can be when the flash goes straight up rather than directly at the subject. The photograph is not so bright and washed out. All of these methods are successful in different situations. Try them out and see which ones work best for you. But no matter what you do when using a small digital camera with the lens close to the flash unit, you are likely to suffer from red eye in your photos from time to time.

4 Reducing Red Eye In Post Production Once a photograph has been taken and the moment has passed there s nothing you can do to recreate it, and when you find that picture has been ruined by red eye it can be disappointing. Lets see if we can fix this problem. Open the photograph from page 2 into Adobe Photoshop. We need to add a new clean layer into the image. Do this by clicking Layer from the top menu, then New and then select Layer. You should be faced with the following window. This is simply asking us what we should call the new layer. In this example I have called it Eyes. Your Layer window should now look like this. You can see the small image of the original photograph is at the bottom, and the new layer called eyes is above it is completely transparent.

5 Reducing Red Eye In Post Production Now we are going to draw two white dots over the eyes in this new layer. To do this select the Brush Tool from the Tools Menu. We need to paint these dots so that they just cover the red area in the eyes. For this example, use a size of about 15 pixels. This can be selected from the tool bar of The Main program (top left hand corner) shown below.

6 Reducing Red Eye In Post Production Begin to draw over the left eye. Click the mouse when the paintbrush is directly over the centre of the red area. You may need to click more than once to fill it. Continue for both eyes. Remember, these white dots are on the Eyes layer rather then on the photograph layer.

7 Finishing Off In order to finish the photograph we need to change the Eyes layer blending mode from Normal to Saturation. This selection is at the top left hand corner of the Layers Window. If you click it you will see a whole menu of blending types, select Saturation. Instantly you will see the white dots disappear and become a dark greyish colour. This hides the redness very well and makes the photograph look more natural.

8 Comparison The way this method works is the white dots are blended into the photograph layer behind using a colour saturation mode. As the dots are white, they will blend without any colour, resulting in a dark grey centre of the eye and a much better finish than before. Before After

9 Un-fixable Cases It s useful to note that there will always be some cases of Red Eye that can never be corrected. In the picture below you can see that there is too much brightness and reflection from the eyes to fix. Although we can get rid of the red, it still doesn t look very natural. Before After