I'm finally getting the chance to write part 3 of my Photography for Hockey Fans series, and I'll beg forgiveness for the long break between part 2 and now!
When I last wrote on this series, I was asked to cover post-production. I'm going to start by saying that I am using Photoshop CS3 for my digital darkroom, and Adobe is up to CS5 now, so I'm a couple of versions behind, but in principle the techniques will be similar, even if the precise methodology is not.
As I write this, I have spent the last several evenings going back through my hockey photos of the past year plus and adding a watermark with my copyright information on it, in preparation for updating my hockey photography web site (http://www.irockthered.net/) with a lot more of my shots, so as I explain the digital darkroom, I will have plenty of illustrations to refer to.Part I: Ice is white - a bit on the basics of color correction
The first thing I do, before I do anything else, is to teach the camera that ice is white. Before I did this, the color of the ice (and indeed the whole image!) was badly affected by the type of lighting in the venue. Verizon Center, Kettler, and the Giant Center all use different types of lighting.
Without going heavily into the properties of light, suffice it to say that each type of light (daylight, tungsten, fluorescent, etc.) has a different color shift. Daylight looks blueish, tungsten orangeish, and fluorescent lights have a really nasty green spike. These lighting types can be compensated for in the camera - if you know what type of light you're dealing with, you can tell your digital camera, for example, "I'm shooting under fluorescent light," and the camera will compensate. But in mixed-lighting situations (where some light is tungsten, some is fluorescent, some is carbon arc light or something equally esoteric), the problem is more complex.
In order to teach my camera that ice is white, what I do is go to "Custom White Balance," and take a picture of the ice. It then registers that this is what white is supposed to look like, and retains the memory of that information while I shoot. While this doesn't guarantee that 100% of my shots will be perfect (nothing does), it improves the white balance so that I have one less step to do in the digital darkroom.
If I do not teach the camera that ice is white, it will attempt to use its automatic white balance setting. In Kettler, this comes out a really fugly shade of pinkish-gray. At Verizon, it's greenish-gray, and in Hershey, it's... well, you get the idea.
Fortunately, Adobe Photoshop has an adjustment, "Auto Levels," which will correct this most of the time. Not all of the time, but most of the time. It's better, of course, to teach the camera that ice is white, rather than depending on your digital darkroom to make the corrections for you.
Here are uncorrected shots from 1) Kettler, 2) Verizon Center, and 3) the Giant Center in Hershey. As you can see, in no case does the ice appear the appropriate color.
Now, after Photoshop's "Auto Levels" correction, here are the same three shots:
Finally, here is an uncorrected shot from the Verizon Center (taken just Tuesday night) after I taught my camera that ice is white.
I'll continue to advanced color correction in Part III. For now, we'll continue into the shadows.
Part II: Correcting for shadows
I've gotten many great shots where the subject's face is in heavy shadow. This is typically caused by overhead lighting and the subject's face being pointed in a direction that is not up. Any light causes a shadow, after all, right? Even balanced lighting like you find at a hockey arena will cause something pointing away from the light source to be in shadow. This is why, for portrait work, flashes are employed. However, since using a flash unit in hockey photography is undesirable due to A) the glass, and B) the distraction effect it has on the players on the ice, you will need to compensate for the shadows in the digital darkroom. Correcting this in the camera may have undesirable effects, such as overexposing ("blowing out") the whites so that any lines on the ice disappear.
Fortunately (again), Photoshop CS3 has a means of compensating for this. It's an adjustment called "Shadow/Highlight," in which you can bump the shadows up without affecting the deliberately lighter areas of the image.
Let me diverge a bit from this topic and talk about exposure.
With film, we are taught to "expose for the shadows, develop for the highlights," which means exposing the film for the darkest point in the photo. This is because in the nature of a photographic negative, the shadows are the areas with the least amount of photosensitive material left after development.
The difference with digital photography is that you are shooting a positive image, so you must reverse this assumption. "Expose for the highlights, develop for the shadows." In a positive image, "white" (remember, you taught your camera that ice is white) will be the bright point in the image. If you base your exposure on the dark areas, you will lose details and will not be able to get them back, because your white will be heavily overexposed, or "blown out."
Here is an example of a shot with overexposed - blown out - whites.
In the digital darkroom, compensating for overexposed whites makes the photo go muddy, because there simply isn't anything there to compensate with. Here's what happens:
and with a -4 stop exposure compensation (done to the extreme as an example only):
Like a photographic negative where the shadows are exposed too heavily, you have nothing to work with for correction, and even exposure compensation won't save you. More on this later.
If you expose for the highlights - the white space - you will have whites that don't blow out; however, you will have to deal with some shadows from time to time.
In an old-style darkroom, this was accomplished through "burning," which is a technique where you make a circle with your hand, place the shadow from your hand in front of everything you *don't* want getting more light, and wiggle it a bit so you don't "burn" the area you're lightening up too much and make it obvious looking. In today's digital darkroom, you still have the "burning" option (and its counterpart, "dodging," where you'd put a tool (or your hand) between the light and what you wanted to expose less, and wiggle it around to keep the exposure even), or you have the "Shadow / Highlight" adjustment.
Here is a photo where the subject's face is dark. We'll go back to an earlier example. Remember that we've already done the Auto Levels compensation ... but it isn't quite enough. Here's the shot with that adjustment done again:
Next, we're going to bump the shadows a little to try and bring out the subject's face. Here's the Shadow / Highlight adjustment with +25 added to the shadows:
That's better! But what if instead of +25, we go to +50?
("NOT TO FIFTY!!!!!")
Look closely at the sweater here... (Yes, this image is larger on purpose). See how grainy it's starting to look? That's overcorrection. We'll discuss that more a little later on. the trick here is to adjust your shadows without overcorrection, so that the areas that are *supposed* to be dark stay dark enough, but the areas that are not lighten up for visibility.
Part III: Advanced color correction
What happens, though, if you have a shot where these two simple techniques just aren't enough to fix the problems you've found? Well, for this, we have the "Photo Filters" adjustment. The Photo Filters adjustment acts just like what would happen if you put a filter on the lens of your camera - without costing you the f/stops that adding a filter on the lens sometimes can. It has the advantage of variable levels, which is something you can't get outside of Photoshop without spending a whole lot of money, hauling a whole lot of filters, and knowing in advance when you have a lighting problem that will momentarily cause your white balance to wig out on you.
The badly overexposed shot I showed above is an example of momentary camera wigout. The most likely cause was some sort of a bright flash of light from a source my camera was not aware of. At Giant Center, this would be the overhead flash units that are sync'd to the press cameras, but I'm not aware of Verizon Center having anything like that. Anyway, why it happens is immaterial. The reality is that even people who have been shooting photos for decades sometimes get into weird lighting situations that they didn't know about enough in advance to correct for on the spot. So, about photo filters.
In order to get into photo filters, I'm going to have to go a bit more heavily into the properties of light and color, so please pardon the impending physics lecture! Everyone was taught in grade school about the three primary colors: red, green, and blue. You can see in this simple diagram another piece of information.
In photography, you have three channels to work with: red, green, and blue. Each of these can be manually adjusted using the manual levels adjustment in Photoshop - and that's useful. But it doesn't always do exactly what you want it to. An easier way to handle adjusting levels of an individual channel is to use the color that is its opposite to compensate. Note the colors on the opposite side from the primaries: cyan, magenta, and yellow.
These were the colors used to do color correction back in the days before cameras could make their own adjustments.
Still, even when you teach the camera that ice is white, you will sometimes have a problem with color balance to deal with. Most of the time, in hockey photography, you will be dealing with too much of the red spectrum of lighting, so you'd compensate using a cyan photo filter. That's overly simplistic, so let's go to some examples. We'll start with an uncorrected photo:
This was taken without teaching the camera about the whiteness of the ice. We're just a little underexposed here... not too horribly to correct, though.
Correcting the levels does this:
But we're still yellowish where we should be white. Adding +25 to the shadows helps some, but it's still not enough:
So we add a photo filter, in this case, a #82 at +20:
THERE's Varly! That's much better, isn't it? The benefit to the Photo Filters option is that you have the full range of photo filters (there are three cyan/blue filters you can use to correct between red-orange-yellowish photos), plus you can add or subtract the amount of filtering involved. I could have turned Varly's sweater bluer than Ovi's eyes, if I'd wanted to.
On to the next example. In this case, I did the adjustments manually for the most part after the first two.
Again, we'll start with an uncorrected photo, this time of Cody Eakin at KCI during the 2009 rookie camp:
We'll start off with the initial two compensation techniques: Auto Levels and Shadows +25:
WOAH, PINK OVERLOAD! The shadow compensation helps a bit, but not much:
Side by side, you can see that Ginger's face needed some help to pop out. But we're still way too pink in this shot. My next adjustment took me into the manual levels adjustor, and the red channel all by itself, where I reduced the red output from 255 (full) to 220.
Better, except now the ice is gray, and so are Eakin's pants. Ew. So, we're going to make two more adjustments. The first is to something called "curves," which I'll explain in more detail later, and the second, to compensate for underexposure.
Unfortunately, I did not save a copy of the shot where I just did the curves adjustment, so here is the effect after the exposure compensation and curves are both done:
And here we have - not a fantastic photo, but certainly much better than we started out with!
I mentioned underexposure before. Underexposure is the opposite of overexposure. Often in the digital darkroom, you can "save" an underexposed photo. If you shoot "raw" images (.arw on my camera) you will have more to work with than you have with a .jpg; however, you will also have to reserve a LOT more space on your hard drive. My camera's .arw files are over 10 megs each in size! Because the version of Photoshop that I'm using isn't that good with handling raw images, and because most of what I shoot will end up online rather than printed, I've stopped shooting raw for now, and I'm getting rid of most of what I have on my main hard drive, since it's all backed up elsewhere anyway, and it's taking up space that I will NEED before the end of the season! In any case, there will be times when an underexposed photograph is just too badly exposed to save. Here is one such example:
Wow, that's dark. Let's see what Auto Levels can do for it:
That didn't help a whole lot, unfortunately. Next adjustment: shadows +50 (NOT TO FIFTY!!!!!!!)
Notice that the photo has gone very grainy at this point. Under normal non-illustrative circumstances, I'd stop right there. This photo is not going to be saveable, and I know it isn't. But for purposes of illustration, I'll try bumping the exposure by +1 stop.
That didn't help, and in fact brought the graininess out even worse than before!
In an attempt to improve it, I used Photoshop's Auto Contrast feature next.
No joy. Oh well; I knew two adjustments ago that this one wasn't saveable.
That's all for now; I'll post a Part 4 talking about Photoshop's effects filters that can be added to help a photo out next, but it will probably be at least a week between installments. Thanks for reading!