Photoshop Video Series - Understanding and Working with Levels

Many commands in Photoshop come complete with an auto button, and not to be outclassed - the levels command comes with 3 of them! The interesting thing here is that, as far as one-click solutions go, they're actually very good at what they set out to do. Join me as we look at how they work and how effective they can be.

Understanding how channels represent colour and how colour works in the first place is a basic topic, it's also an important one that will serve you a good foundation of knowledge as you motor you're way through this series. We'll also take our first look at the histogram and turn a series of lines into some cleverly spoken words.

It's time to realise that those cleverly spoken words were actually a full-blown conversation between the pixels in our image and our ears, spoken by the soothing voice of the histogram. Now comes the time to understand terms such as contrast, clipping and other references used in the world of photography such as high and low key images.

It's time to open up the levels dialogue box, roll up our sleeves and get down to some good old fashioned image editing, but not before we take a look at why we're not using the more straight-forward brightness/contrast command to amend the brightness and contrast of our images.

As powerful as editing the composite histogram may be, it pales in comparison to the results that come from making individual edits on a channel-by-channel basis. Sounds complicated? Follow the instructions from this video, add a little creativity and you'll be wandering in and out of the channels like a walk in the park.

Some people claim you should avoid clipping like nothing else in existence, and whilst that ideal has some merit - the reality is you'll no doubt be faced with the problem one day. Therefore it's time to look at some creative solutions and realise that sometimes the best way out of trouble is to take a different route home.

It's well documented that Photoshop provides custom keyboard shortcuts for many of its popular and important tasks, not least the levels command, so it's only natural we take a look at navigating inside the dialogue box using its well designed, and often more accurate keyboard variations.

Most of this series is focused on increasing contrast in our images - but what happens for the occasions we want to reduce it? Enter the output sliders! By using the output controls we gain more accuracy in deciding the exact brightness level of shadows and highlights in our images, which can complement our ever increasing knowledge and allow us to take our creativity even further.

The more we know about a subject, the further we want to push ourselves to create the unimaginable. Before long we're building complex compositions from a single flat image, and the more complex we get, the more scope we need for readjusting settings that looked perfect five edits ago but no longer stand the test of time. The world of non-destructive editing inside levels brings about a whole new concept to an already able set of editing techniques.

In the world of non-destructive image editing with the levels command - the adjustment layer is king. Sitting at the top of the layers palette it gracefully and parametrically controls every pixel below it, and when used in combination with its equally powerful ally the luminance mask it becomes a true Photoshop force to be reckoned with.

The 16 bit mode allows us to introduce 32,000 luminance levels of data per channel, which in theory gives us access to billions of colour variations inside one RGB image, enough to make any number of extreme edits and not produce a single sign of colour banding or posterization. Sometimes seeing is understanding, and understanding is believing.

The levels dialogue box allows us to take control of the three automatic operations in auto levels, auto colour and auto contrast. Instead of just pushing a button and hoping for the best results, we can adjust black, grey and white points as well as control the percentage of pixels we want to ignore before finding the true base luminance for the given value. If that sounds confusing then this video's for you.

The term 'neutral colours' will feature a lot in the latter stages of this video series, so it's important to form an understanding of what it means - and how it can help us keep our colours accurate and true. On the other hand, adding saturation is the act of taking the colours, or more accurately the hues of an image, and making them more vivid by raising the intensity level - which is yet another level to understand!

The eyedropper tools inside levels have the ability of setting specific values for specific pixels which is ideal when adjusting shadows, midtones and highlights. In the honour of levels we'll look at the eyedroppers and the theory of posterization followed by a full blown creative party as we play with those aforementioned eyedroppers, avoid the party-pooper that lives by the name of colour banding, and perform a very special party trick by transforming the grey eyedropper into a colour replacement tool. Doesn't time fly when you're having fun!!

So we know what shadows and highlights are, and we also know a way of locating and using them in conjunction with the relevant eyedroppers - but surely there must be a more accurate way of finding the brightest and darkest pixels inside an image? Well I'm glad you asked, as with assistance from the threshold command, the colour sampler tool, the info palette and the eyedroppers we can achieve pinpoint accuracy in a modest amount of time.

Modifying skin tones can be a tricky task, thankfully within levels we have a number of fully-adjustable yet simple techniques that wield some great results. Some of these results depend on the user’s perception of what's right, or what's wrong, with the colour of the skin, other results are aided by a library of skin tone swatches that are prepared to work overtime to get you the results you demand.

With one foot inside the CMYK colour space but the other firmly rooted to RGB land we begin to harness the power of number-based skin tone adjustments using the colour sampler tool and the levels command. Altogether a more involved but highly rewarding way to work that's employed by studios and portrait professionals around the world.

It's time to summarize the RGB, luminance and Colour histograms available inside Photoshop, and talk more specifically and indeed more technically about the statistics available in the expanded view. It's not necessarily about how to ask questions, it more about deciphering the often misunderstood answers that the histogram palette is shouting out!

Photoshop produces red, green and blue histograms inside an RGB image, when it's done it puts the results into a composite version and displays it as the standard view. How that composite view is calculated decides how we see clipping inside our images - and as you'll bear witness, things aren't always what they seem!

Because the human eye doesn't see red, green and blue light equally we need a reliable way of representing the brightness of a pixel independent of colour. And so steps up the luminance histogram - the most accurate way of spotting clipped shadows and blown highlights threatening the very existence of your image!

Made popular by the Camera Raw plug-in that ships along with Photoshop, the color histogram contains all 3 RGB channel histograms inside one window, giving a visually pleasing reference to colour information, how the channels interact and where exactly they don't.

So we know the difference between colour and luminance information, now's the time to look at dividing the two and working on each individually. Whether we're doing that with blend modes or the highly theoretical Lab colour space we're going to be opening our eyes to a whole new universe.

A colour cast is when the colour of an image shifts towards a specific hue, say green, to give the whole image an unsightly green tint. The reasons behind this and the resulting cast can be as numerous as the tools available to fix it. For this reason we'll take a classic example and put things right both manually and automatically.