Color Enhancement Tutorial

This is just a quick trip through my methods for achieving better color balance on digital photographs. Sometimes they look good right off of the camera, sometimes, not so much. But with the tools at our disposal these days, that can be rectified fairly quickly and easily most of the time.

Now, let me preface this by saying that it's always better to start with quality. In an ideal world, we'd have all the bright, white light we need for every shot and we'd never have to tweak colors or enhance contrast in a photo editor. But, this isn't an ideal world. And sometimes, like in the last picture we're going to work with here, you have just seconds to get that shot, and any time fiddling with lights or even camera settings means you've lost that priceless moment forever.

So, you've got your snapshot, but the color is all wrong. The details are there, and you know you can bring them out, but where do you even begin?

I suppose, like with all things, we should begin at the beginning. Here's a snapshot, straight off the camera. Obviously, this one is scaled down to keep this tutorial from becoming a computer destroying menace. Sometimes you get lucky, and have what is basically a pretty darned good picture color-wise. But, even in cases like this one, it isn't exactly what the human eye would see when there in person, and so we set out to correct that if possible.

The first action to take in your photo editor when starting to color enhance a photo is to add what I've come to think of as the smoothing layer. It brightens the darker areas, and darkens the brighter areas, and essentially brings a better balance to the picture. To create the smoothing layer, follow these steps:

1. Duplicate the base background layer and put the duplicate above the background layer.
2. On the new layer, desaturate the color.
3. Invert the now desaturated new layer.
4. Set the new layer to overlay.
5. Blur the new layer just slightly.

Here's a quick run-down of what each step accomplishes.

Step 1 is pretty self-explanatory. Without it, none of the others are possible.

Step 2 gives you a greyscale image to use.

Step 3 gives you a reverse light mask to apply to the original image. This is the important bit, as it adds the smoothing effect we're looking for.

Step 4 sets that reverse light mask to be transparent, so that the original colors can come through while being filtered slightly by the new reverse greyscale mask.

Step 5 might seem like an odd one to include. But, strangely, I've found that leaving this layer unblurred causes a lot of clarity problems down the road. Basically, any super-bright hot-spots in the picture get lost. The eye uses these hot-spots as points of clarity in any picture. Blurring slightly reduces the filter's effect on these hotspots, while not losing the basic properties of the reverse greyscale mask, thus returning clarity. On a picture straight off the camera, I usually need to run a gaussian blur of about 12 to rectify the clarity problem. Scaled back this far, I ran a gaussian blur of 5 and it seemed to be OK.

Now, we've got a more balanced picture, but somehow we lost a touch of the color that was there previously. How do we get that color back?

This step is very simple, and extremely noticeable. This is the step for pictures that are already pretty well lit up front where everything begins to pop color-wise.

We add a third layer to the image, starting again with the base background layer and duplicating it. Move that layer to the top of the image in the layers dialog, and then turn it into an overlay. In some cases you need to back off the opacity setting a little to prevent it from oversaturating the colors, but in this case the color-pop is quite nice, and not that far off from what I remember seeing standing at the dock that day.

Depending on what you want to achieve, this might be the point where you stop and call it good enough. The colors are brighter, enhanced, and the picture is overall smoother in appearance than it was at first. But, in this case, I have one more step I want to take. Partially to show the effect of single-color filters, and partially because this isn't the color I remember from actually being there that day.

I'm sure there's more than one person who will read this, see the filter layer, and say to themselves, "What? Why?"

All I can say to that is, remember Superman. Why is Superman so powerful on Earth?

It's the yellow sun.

I actually picked up this tip from television shows and movie reels. It's a visual arts thing that's been known for decades, but seemingly nobody talks about. Single color filters can be used to differentiate scenes from one another, set a mood, or just plain clean up a shot and make it appear more real. A lot of popular shows use and abuse this method. 24, for example, uses and abuses the yellow filter on their outdoor scenes. Especially their industrial, daytime, outdoor scenes. Their headquarters is ridiculously blue-green filtered. Remember The Matrix? The difference between the "real world" and the "Matrix world?" Green filters. How about Alias? Dark blue, almost violet filters at SD-6, bright, nearly white-green filters at CIA headquarters, again with the yellow on outdoors daytime shots.

The point is, it's everywhere. And you most likely don't even notice until you've seen how easy it is to do yourself.

So, why? Camera manufacturers tend to calibrate cameras as if the sun were "white light." It is not. It's yellow light. Not deeply yellow, and the human eye and mind can easily compensate for it, but it is yellow. There's nothing wrong with a camera that's calibrated to see the sun as white light. It's just something to keep in mind when you are tweaking digital photos.

(Please note that this is not to say all cameras are calibrated to see the sun as white light. Also, better, more expensive cameras, give you color temperature setting so that you can calibrate your own "white light" setting. The above paragraph is a generalization, and like all generalizations, is only true of a small number of cameras, and the default settings of a far larger number of cameras that can be manipulated to give different results.)

So, as I'm looking at this picture I remember the water being more green that day. Hey, it's a lake in Fairmont, Minnesota right at the beginning of fall, of course it's green. And so, I go to add a color correcting layer into the picture to see the picture the way I saw it that day when I was there.

All that rambling to say, a color filter is simply a single color layer set to be an overlay and having it's opacity lowered until it lightly filters every pixel to the level you want to see it filtered. In the above example, a pure yellow filter set to 20% opacity overlay gives exactly the results I wanted to see. Blue-green water, the wood of the dock more on the brown side, less on the grey, the brown algae along the banks is visible, and the sky even looks brighter and more vibrant.

Here's our before and after shot. Notice how much different the picture looks all through the use of simple filters, duplicate layers, and a single-color overlay in the end?

But, as I usually do, I started with the easy one. What do you do when you start with a mess like you see below?

What the heck is this?

Well, actually, since I already know, I'll tell you. It's a shot of my backyard in the middle of the night. There's some small lights on the house off to the left and behind the camera, but it's not enough to illuminate the shot for a camera that can only hold the shutter open for three seconds. So what's the use of a picture like this, and how will we ever make out anything in it?

Following the same initial step as we did in the first scenario, we begin to see something in the shadows. Remember how to create the smoothing layer? Duplicate the background, raise the new layer to the top, desaturate, invert, blur slightly, set to overlay.

For a nighttime shot, you often need to brighten the entire picture. Sometimes a lot. In this case, I added a pure white layer to the top of the picture, then set the white layer to overlay and left it at 100% opacity. It brightened the shot considerably.

If you have a nighttime shot to clean up, experiment. Some cameras have a weird blue or red haze on night shots that you need to compensate for. Or, on video caps, you may need to compensate for an odd greenish night-vision sort of color. Remember your color wheel from school and try to remember what's the opposite of the color you are trying to balance out. That will be the color you want to filter with. But note a pure layer of just that color in a dark shot. That color mixed with a whole lot of white. Not red, pink. Not green, but bright whitish green. Not blue, but baby blue. You get the idea.

In this case, the pure white layer oversaturated the shot slightly and made it appear washed out. So, to compensate, I went back to the base background layer, duplicated it, and moved the duplicate layer up right under the white filter layer. Then I set it to overlay and lowered the opacity to zero. I then slowly moved the opacity up until the colors began to come back to the picture. Notice the greens and yellows in the leaves compared to the previous version?

And here's our before and after. Quite a dramatic difference this time.

What about indoor pictures?

This was one of those previously mentioned priceless moments that you don't want to let pass by. The look on Rita's face says so much that I couldn't let it pass me by. So, my camera wasn't ready for the low-light. And, our living room is primarily green, with really yellow lighting, giving the entire picture an extremely yellow tint. So how do we pull it back from the brink?

We'll start with the same-old, same-old, the smoothing layer. I'm going to assume at this point that you know how to create the smoothing layer. And, if you don't, you're probably able to scroll back up the page to one of the other two times we walked through it. Go ahead, I'll wait.

It improves the picture quite a bit just getting the smoothing layer in there. Some people are big believers in using multiple smoothing layers, but I've found that clarity really suffers when you do that to try and brighten a dark shot. Instead, I go right for the white filter approach.

This is the same method discussed in the previous picture walk-through. A 100% Opacity overlay of white to bring up the brightness.

Now, to compensate for the colors getting a little desaturated, I add in another duplicate of the background and move it up right under the white filter, then lower the opacity to 0% and slowly raise it until I'm happy with it.

And, to compensate for that yellow tinge to everything, I add in a bright-blue filter layer, set it to overlay, and lower the opacity to 40%. This nicely counteracts the overall yellow tinge to the picture. But what about that odd extra-yellow bit that still shows up in the upper right hand side of the picture?

I added in a dark blue filter to couteract the remaining stand-out yellow spot, and to compensate for the overly lit area to blend that area of the picture back in with the general tone of the rest of the picture. The way I did this was to mark a hard-edged line around the yellow bit with the pencil tool in the correct color, fill the lined area with that color, then gaussian blurred it at a setting of about thirty to soften the transition into the filter, set the layer to overlay, then lowered the opacity until everything seemed to blend together properly.

Once you get used to working with color filters, you can spot-filter out most any color-region problems you see. It's not quick or easy, but it's doable.

And again, here's our before and after. Much better, as now you can see the questioning cuteness of the little furry Rita.

And that is my "quick" run-through on how to enhance colors in digital photos. If you have any questions or any other specifics you'd like discuss, contact me.

Enjoy.