Digital Diversity

There seem to be two kinds of people in the digital photography world when it comes to post processing. Those that do it and those that don’t. I have met many people that seem to think post processing an image is cheating. This really doesn’t make any sense at all. That’s like saying that people cheated with film cameras by using a darkroom to process their images. After all programs like Photoshop are essentially just a digital dark room. Surly its more of a cheat to try and get a camera that does that all for you. I was always under the impression that cheats did as little as possible, not extra work.

Anyway I am sure you can guess i’m firmly in the field of agreeing with post processing. So this tutorial is just that. How to process your photo’s in Photoshop. It will involve colour correction and sharpening up your image to finish it off.

The following tutorial was done in Photoshop elements 7. These techniques can be done in most versions of Photoshop.

Before we start i need to explain what an adjustment layer actually is. It is a way of correcting an element of an image (such as the levels, contrast, saturation etc) without permanently effecting the pixels on the layer. It means you can play around with the adjustment and if you don’t like it, its not a problem because you can just delete the adjustment layer or use the mask to hide parts of it you didn’t like. Its known as non-destructive editing. Some adjustments cant be done on an adjustment layer and have to be done directly to an image layer. These are destructive, which means the changes you make to them are permanent. They directly affect the pixels on that layer.

If that makes no sense try thinking of it like this.

You want blacked out windows for your car (I have no idea why, maybe your famous). You can either get tinted windows or you can put some dark film over them to get the same result. The tinted windows are permanent so if you don’t like them there isn’t much you can do bar get new ones. If you put a dark film over them you get the same result but if you are unsatisfied you can just remove the film.

So essentially the adjustment layer is like a filter being placed over an image. A bit like adding a filter to the front of your lens.

I often shoot my images in fine JPEG mode with all the picture adjustment settings on default. I find this gives me the best result to process images myself. If you turn up the contrast or saturation settings on your camera you may find that processing them is harder. The camera may over saturate a certain colour which can cause you to lose detail that you can’t recover. Using post processing you can do all this far more accurately yourself.

So first up we need an image. I looked through some images I had taken and found a ’snap’ of a duck that I hadn’t retouched yet. In fact it was classed as a ’snap’ which means it would have just sat on my hard drive so I may as well put it to some use.

What I have learned about the fz-28 in particular is that it leaves a slight red cast over the image. You may not notice it just looking here but as soon as you correct it, it becomes quite obvious. Each camera is different however so you may need to alter this first step depending on how the images come out of your camera.

To correct this red cast I open up a level’s adjustment layer. Go to Layer > New Adjustment Layer > Levels.

You will find it opens up a screen with a histogram on it and some places with numbers that you can change. If you are using Photoshop CS, some versions will have a different window that might already be open that will change depending on what adjustment layer you have selected. If you cant see it go to Window > Adjustments and it should appear. It will look similar to the ones in the sample images.

A histogram is a graph of the exposure for the image. There are many things you can do with this to correct lighting problems. The left of the graph is the shadows and the right is the highlights. The middle is the mid tones. Have a play with the sliders and see what happens but make sure you reset them before carrying on with this tutorial.

A common use of the Levels is to bring in the left and right sliders to meet the ends of the histogram. In a lot of cases you will find this corrects the lighting on an image. Sometimes, however, it doesn’t give a pleasant result. Your best bet is to try it to see if it works. If not adjust them until you have the desired result. For this photo I am skipping this step entirely as it doesn’t give the result I want.

In the image, where it says ‘Channel’, it will currently say RGB. Click this and a drop down menu will appear. Now select red. This means you are now only affecting the reds in the image. On the histogram, the left hand number box will say 0. Change this to between 6-10. You will notice that the image suddenly looks less red. If your image is like this one it will already look a bit better.

Click OK.

Now we need to use another adjustment layer. This time its the one called brightness/contrast. So add this the same way as we did with the level’s adjustment layer. Layer > New Adjustment Layer > Brightness/Contrast.

A window will appear that looks like this

This adjustment is very simple and very useful. If you have an image that’s a bit to bright or dark then you can move the brightness slider to correct this. It’s a fairly simple method but useful for beginners. However in this image we will leave this alone for now. As a basic rule for my images is that I drag the contrast to about 25 as a starting point. Move it up and down till you think the contrast is about right. In this case 25 seemed just fine. You will notice the colours stand out a bit more as well as the detail. However you may also notice that some areas have not become a bit to dark. Don’t worry about that as it will be corrected later on.

Click OK.

We have corrected the colour cast and the contrast. The next thing you will want to adjust is the shadows and highlights. There is no adjustment layer for this so make a new layer that is a flattened layer of everything we have done so far. Do this by pressing shift + ctrl + alt + e. The new flattened layer will appear above the other layers.

With this layer selected go to the adjustment’s menu at the top of the screen and find  ’shadows and highlights’. It will open up a new window.

This is a very powerful tool. You can make huge changes to the exposure of your images shadows and highlights but don’t go overboard. The slightest change can make a big difference. Some images you can get away with making large changes but a lot of images will end up with a problem called haloing. This just means you will have little halo like glows around everything. For images where the exposure is fairly good in the first place use small numbers. For example I lightened the shadows by 2% to bring back the light to the ducks head and I darkened the highlights by 4% to bring a bit more detail into the lighter parts of the image.

Once your pleased with the exposure click OK.

Time for one last adjustment layer. This time its going to be the hue/saturation adjustment. So create one by going to Layer > New Adjustment Layer > Hue/Saturation.

In the image above I have shown 2 copies of the adjustment window. Call the first one fig1 and the second one fig2.

In this window (fig1) we have 3 things. Hue, Saturation and Lightness. The Hue changes the colours, the saturation, somewhat unsurprisingly, changes the saturation of the colours and the lightness adjusts how light or dark the image is.

As default, the drop down menu next to the word Edit will say master. This means changes you make will affect all the colours in the image. So as a first step let’s make the colour pop a little bit by increasing this to 10. Straight away you should see a difference. Now comes the clever part. You can choose from several colour channels the image is made up from and edit them individually. To choose the colour click on the drop down menu that says master. The options will look like they do in fig2. Each image will be different in what you want to change. I know the duck has a natural yellow colour so I will increase that. Select yellows. Now increase the saturation to about 10. I also want the blue to be a bit more vibrant so now change the drop down menu to blues and increase the saturation a little bit. Do the same to the cyan and you will notice the water has turned a slight blue colour.

Overall the changes are subtle but add up to give the image a lot more impact. As I said before, every image is different so work out what colours you want to stand out and adjust them. For example a bug with red eyes you will want to select the reds and up the saturation for those.

Your now almost done. The image should be colour corrected and looking a fair bit different from the original. Even now I will make these changes and will be fairly shocked how different the shot looks. I could have sworn my original photo never looked that bad before. Bit the reality is…. it did. It’s just hard to tell with nothing to compare it to.

The next step will often be noise reduction but I have left this out for now. You will generally want to use a third party software such as neat image or noise ninja as Photoshops noise reduction isn’t very good. People are obsessed with reducing noise (including my self at times) but it’s not that important for general photo’s as you normally cant even see it unless zoomed right in or making large prints. If you do want to do noise reduction then the time to do it is after all the colour correction and just before you sharpen the image.

So on too sharpening. First thing to do is create a new flattened layer in-case any mistakes are made. Do this with  shift + ctrl + alt + e. This way if you make a mistake you can delete the layer and start this section again. Make sure the new layer is selected. There are two methods you can use. In elements you can use either the UnSharp mask tool or the Adjust sharpness tool. Both are very powerful. If using CS you have other options as well. CS however doesn’t have the simplified adjust sharpness tool (instead it has some much more specialised ones).

So if you are doing this tutorial in CS you will need to use the UnSharp mask tool.

In CS this is in Filters > Sharpen > UnSharp mask

In elements it is under the adjustments options.

a window will appear like this

Your options here are – amount, radius and threshold.

Amount – the actually amount of sharpening done

Radius – sort of like the frequency of pixels it effects

Threshold – is like a buffer to adjust how much is effected.

As standard I leave my Radius on 1.5 and my threshold on 3. It’s the ‘amount’ I tend to change. I  start on 60% then adjust this until the image looks sharp.

Click OK.

The other method is to use the adjust sharpness tool. Personally I tend to use this one rather than the UnSharp mask.

This time you don’t have the threshold option but you do have a different one called remove. Make sure this is on Lens Blur, if not select it from the drop down menu. Also I leave the More Refined tick box checked.

Again, as a standard rule I leave radius on 1.5 but this time I have my amount on 30%. This actually tends to be the right amount for most images but just move the slider till your happy with the result. Then click OK.

Important – don’t use both of these one after the other. Use one or the other.

Your image is now colour corrected and sharpened.

And here is the original image again so you can compare them easily.

To really see the difference, view them both in large side by side.

Once you have the hang of this it should only take a few minutes per picture. Time worth spent I like to think.

All the tools you have used in this tutorial are capable of a lot more so why not have a play with them. One thing to try out is changing a colour using a hue/saturation adjustment layer. Take a picture of a flower, open it up in Photoshop. Then add a hue / saturation adjustment layer. From the drop down menu select the colour that is the main colour of the flower. Now move the hue slider back and forward.

Have fun.

Tags: colour correction, colours, contrast, duck, elements, highlights, hue, levels, lighting, photoshop, saturation, shadows, sharpening, tutorial

This entry was posted on Thursday, August 13th, 2009 at 10:18 and is filed under photoshop. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.