Photoshop 101 - Part 2

5 November 2012 9:33:01 AM AEDT

In the last blog entry of this series we discussed how to open, save, crop and re-size your images. In this entry we will take it a step further and talk about adjusting brightness and colour levels.

Levels Adjustment:

Let's say you have taken a picture which, while otherwise ideal, is just a bit too dark. There are a few ways you can try and amend this, and the quickest and easiest is to use the Auto Levels tool which is accessed by going to Image, Adjustments, and Auto Levels. Auto Levels is a quick and easy way to go, but is far from being the most accurate. After all, what a computer algorithm thinks is best might differ from your own preferences.

The more accurate approach is to select Image, Adjustments, and Levels which will bring up a dialogue box with a histogram. This dialogue box lets you adjust your input and output levels. The histogram indicates how well exposed your image is and the range of tone which is dispersed throughout your image. If your image is well exposed the histogram will generally peek in the middle and taper off down the sides. If it is an image which is dark and shadowy (or “Low Key”) the histogram will group toward the left hand side. If it’s a shot with a lot of bright white colour (“High Key”) it will group to the right. Sometimes you want High Key and Low key images, and it is always best to tailor your image to what suits the subject, framing and composition.

Underneath the histogram you will see three arrows. The first indicates where pure black is, the second is middle grey, and the third is pure white. If you drag the two outside arrows closer to where the histogram begins to taper, this will up the contrast in your image so you have brighter highlights and darker shadows. If you photo is too dark you can carefully slide the third arrow along to the left, which can lighten your image. You can also shift the mid tones by moving the middle arrow. If your image is still too dark you can adjust the output levels by playing with the slider at the bottom. This works in a similar way, by letting you lighten and darken your entire image as you see fit, rather than just the highlights. Play around with the settings and get to know what levels suit different kinds of images.

Image colour and saturation:

Sometimes the picture you have taken seems to have the wrong colour cast; it’s too blue, too orange, too green etc. To fix this we can bring up the Hugh/Saturation tool, which can be found under Image and Tools. This brings up a dialogue box with three sliders: Hugh, Saturation and Lightness. By moving the Hugh slider around you can adjust the overall colour cast of the image. Feel free to play with this slider as much as you like, but remember that with this option less really is more, and that subtle adjustments are usually all you need.

Of course, there is the odd occasion where you get a picture which would really look better in black and white. This could be because the colours are too dull or bland, and/or the fine detail or texture would be better seen without the distraction of colour. This is where your second slider comes in; if you slide the saturation back toward the right, your picture’s colour will fade to black and white. Conversely, this slider can also be used to boost the brightness of some of your colours, but again less is more.

The trick to getting a really good black and white picture is to make sure you have some bright white and some pitch black in the shot. If your image is just a wash of shades of grey without proper highlights you get an image without any real depth. So, once you have desaturated your image be sure to go back and play with your levels as outlined above. Another useful tool is Contrast, which can also be found under Image and Tools. This slider lets you adjust your grey tones simply and easily.

So now that we have tackled colour and brightness levels, Part 3 will focus on erasing unwanted elements and basic restoration techniques. Until then, happy shooting!


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