Contrast in photos
If you are reading this, you have probably heard people moaning about lack of contrast in one of your pictures. I am sorry about that, but — really — it is one of the most annoying things in the world. The medium of photography allows you to enhance the way you see the world, so you have an option of showing what you would like to show better. When the option is there – why not use it?
This is the picture we’ll be working with for now. I know it isn’t exactly the best picture in the world, but at least it is bland – it is nothing short of boring. Why? Well – mainly because nothing is the way it should be.
I believe that, in photography, black should be black. White should be white. In most cases, there is no real excuse for having almost-white and almost-black as the darkest and lightest point of your photograph (unless it is part of a photographic effect, in which case this all doesn’t apply.)
It’s worth noting that this article is aimed especially at beginners, who aren’t that clued up on Photoshop. If this doesn’t apply to you, you may just want to dive right into the adjustment layers instead!
You have probably seen the brightness and contrast tool: It is very useful, but clumsy to use. Instead, we will be using the Levels tool. You find this tool by pressing apple (or control, if you are using Windows) and L. Or you could go to Image – Adjustments – Levels.
This tool allows you to see a histogram of your image, before changing things so they fit into the colour space you are working in.
When you open the menu, you see a few things: Three eyedropper tools down in the bottom right. If you want to use the eyedroppers, pick the left one (shadow), and click a portion of the image that you feel should be absolute black (i.e. RGB value r0, g0, b0). Now, take the rightmost eyedropper tool (highlight), and click a portion of the image you think should be absolute white (i.e. r255, g255, b255). The levels tool will then adjust your image for you.
But… What is the middle tool, I hear you ask. That is the gray point tool – or white balance tool, if you will. If you have any portion in your image that is neutral gray (preferably a 18% (r50, b50, g50) gray, but any neutral gray will do), you can select this dropper, and the Levels tool will change the Red, Green and Blue channels separately, to allow you to fix a mis-measured white balance. It is quite effective, actually.
For this tutorial, however, I will be using fully manual corrections on the RGB channel. On the top of this dialog box, you can see RGB. This means that all changes you make will affect all the channels. You can, of course, adjust any of the channels separately, but if you feel you are ready for that, then what the hell are you reading this guide for?
Anyway. When you look at the histogram, you can see that in the left and right ends of the histogram, nothing is registered. This means that the picture I am using as an example actually does not have any “real” black or “real” white in it. In other words, it uses only a limited band of the spectrum. Which – if you ask me – is a waste.
So, our first change is to make sure that there is real black in our picture. Do this by sliding the left slider towards where the histogram starts registering properly. If you want more contrast, you can slide it past where the histogram starts, as I have done here. What happens then, is that some of the details in the dark areas of the image are lost, and it just becomes black. Which gives an illusion of high contrast. Which is what we are looking for.
The result of the above change is this:
We do the same to the highlights:
Move the right slider to the left, and see the result:
As you can tell, the contrast is now a lot better. But now the whole picture is a tad dark. You have probably already noticed the middle slider. You guessed it, this is your brightness slider (well, not strictly – matematically, it just weighs the brightness in the image differently, by ’stretching’ the histogram one way or another, or ‘gamma correction’, as you might know it. For all practical uses, however, look at it as the brightness slider)
Moving the brightness slider to the dark side makes the picture lighter, and vice-versa. It seems unlogical at first, but the explanation is the mathematical thing mentioned above.
I slide the brightness (gamma) from 1 to 1.16, and the result:
Now, I am almost happy, but there is still one problem; Because we have been playing with the layers, the colours look a bit unrealistic. So I go to the Hue / saturation control (ctrl + u, or have a look in the image -> adjustments menu), and pull the saturation down a few tads.
So here we go; Your classic before-and-after pictures:
Of course, the image still sucks, because the original photo wasn’t particularly good. It does, however, explain how the levels tool works.
Taking it to the next level
Now that you know the basics, it’s time to go further in-depth. Contrast is one of the most common mistakes photographers seem to make, so it makes sense to learn a little more. If you are interested in increasing contrast in post production, you’ll want Matt Greer’s website, especially his in-depth introduction to curves.
Good luck!
My day job, if it can be called that, is being a writer. I've got one book out there so far and it's awesome, so go ahead and buy a copy! It's available from 
In front of you, five hyperactive men with guitars, drums, and microphones. Behind you, five thousand fans. In your hands, a camera... You're going to need more than just a little bit of good luck to pull this one off. That's where this book comes in.
Take a Canon EOS 450D. Attach a Canon 50mm f/1.4 lens. Hit the streets of London. See what happens.
Insights, suggestions and comments
Great tip, I see a lot of photographers struggle with this type of thing. It really IS a 1 minute operation, and when you combine a levels adjustment with a curves adjustment, the photo can turn out 1000% better than it was straight out of the camera. I use the levels and curves so much, I’ve actually made a Photoshop action to lay down the two adjustment layers for me when I push F3. I’m all about being lazy.
Nice. Someone is actually recommending levels for use in actual, direct image manipulation as a rule, rather than as an exception.
I highly recommend you find a new use for the levels tool, and learn to use the curves tool (on an adjustment layer; they exist for a VERY good reason) for your contrast adjustments. The controls aren’t as obvious, but they’re far more powerful.
Reserve the use of levels to times when you want to limit the output range (ie, reduce contrast by rendering ONLY the highlights OR shadows of the image for special effects, particularly in design), or to manipulate a selection or layer mask and its effects on the image.
These 3 tips will do far more for the quality of your images than a million tips on using levels for contrast.
“I believe that, in photography, black should be black. White should be white. In most cases, there is no real excuse for having almost-white and almost-black as the darkest and lightest point of your photograph (unless it is part of a photographic effect, in which case this all doesn’t apply.)”
This is why you are misusing the tool. You do not understand the basic concept of the light you are working with. The truth is the exact opposite of what you’ve stated. In reality the only thing that is truly white (255,255,255 in the scale you’re using) is a completely blown out (colorless) light source or specular highlight such as jewelry or a chrome bumper. And the only time something is truly black (0,0,0 in 8-bit) is if NO photons reached the sensor.
Now, if you want your 15,15,15 range to be 0,0,0 and your 240,240,240 whites (such as a dress, which should have detail even in the brightest portion) to be completely blown, then by all means send it off the charts. Clip the image. Do it because that’s the way you want the image to look. Do it because you have decided that it is the appropriate treatment for your image. Heaven knows there are infinitely many cases where this is the point, and I do so on a regular basis.
But don’t do it thinking that it’s technically correct and that you have to have some specific artistic vision to do it any other way.
And don’t do it because you think that’s the correct way to add contrast. MORE CONTRAST DOES NOT MEAN ZERO SHADOW AND HIGHLIGHT DETAIL. Master the use of curves and your contrast will sing without losing definition in your images. Once you understand it you can selectively apply contrast to the shadows while retaining the existing values in the highlights.
And definitely don’t go around telling other photographers that your misunderstanding should become their understanding.
Seriously, your final image looks like crap, because there’s nothing white in the scene and yet you’ve rendered it as though there is. If that’s the effect you want then that’s great, but to say that this should be done to all images is plain and simple ignorance.
“Nice. Someone is actually recommending levels for use in actual, direct image manipulation as a rule, rather than as an exception.”
There’s nothing intrinsically wrong with using the levels tool like this. Of course, Curves is better, or even shooting in Camera Raw, and then using the raw importing tool to make these kinds of changes. What you fail to notice is that this is an introduction on the topic, for photographers who post photos that look too flat and boring, rather than an in-depth photoshop tutorial — That’s where the further reading comes in.
Interestingly, I’ve already queued up an article on adjustment layers to go live in a couple of days, for the more advanced photographers :-)
“You do not understand the basic concept of the light you are working with”
I think that’s a bit of a tall claim. The difference is that I try to explain complex concepts to people who have little or no photographic skills, or who are downright afraid of using tools like Photoshop. Also bear in mind that many budding photographers use Photoshop Elements (which lacks a Curves tool), or other, simpler and cheaper image editing packages.
I know full well that blown-out (i.e perfect white) is a fault in an image. In fact, I’ve ranted about this at great length before. However, if you aim to have A SINGLE PIXEL (i.e the brightest pixel in an image) as perfect white, and A SINGLE PIXEL as perfect black, it ensures that you are using the full dynamic range expressable within the limited confounds of 8-bit imaging.
Finally, you’re completely right about your comment about the final image. However, the point stands, in that this image is an illustration of how contrast makes a difference on a photo, which was what needed to be illustrated.
I think I can’t fault your argument on anything you say (apart from the things you say about me directly, but I’ll let them slide), but the quirk is that this article is written to a very specific target audience (digital darkroom newbies), rather than to photographers who know it all already.
I’m planning to do more in-depth more aimed-at-power-users articles on the same topic. When I do, I promise to link to them from this article, so there’s a gradual progression.
- Haje
From Jon’s Comment:
“Reserve the use of levels to times when you want to limit the output range (ie, reduce contrast by rendering ONLY the highlights OR shadows of the image for special effects, particularly in design), or to manipulate a selection or layer mask and its effects on the image.”
If you’re not using the levels adjustment prior to curves, you’re not getting the most out of the curves tool. More times than not, an image won’t fill the histogram from shadow to highlight (as shown in the tutorial). The levels tool will just stretch out the histogram to give the picture a larger tonal range. Then, if you want to adust mid-tones, the curves tool will be more effective. You shouldn’t be moving the corner anchors in the curves adjustment — that’s what levels are for!
Excellent topic and post. Getting the correct contrast for photography can be one of the most complicated things for a photographer. You are completely right about using the levels and curves for adjusting the contrast. Also the shadow and highlights tool is another great option to bring out the lights and darks in an image.
Trackbacks
Share your wisdom