The Fabulous Aperture 3 Curves Tool

I don't talk about messing about in post much. Probably because I despise it so much. Truth is that's one of the things I really miss from the days when we all shot film. Ubiquitous, cheap, out-sourced post processing. Well that and I've spent far too much time in photoshop than I would wish in two lifetimes. Every once in a blue moon when I actually am going to print something, or when I do the occasional job here or there, I do actually futz around a bit on my own images. Oh yea - and I mess with other photographer's images a lot too. Almost forgot about that. Here and there I've mentioned how wonderful I think the Aperture 3 curves tool is but never really mentioned why.

During a recent email exchange with a reader and fellow Aperture 3 user I suddenly realized that not all of you may have dug into it's virtues. Today I'll attempt a quick drive-by to show you a somewhat contrived illustration as to the innovation contained within. Contrived in that I am going to do some extreme things for educational purposes rather than any sort of recipe for success. Specifically I'll walk you through a random shot from my Mirror-Mirror project I made a few months ago. The screen shot at the top represents where we'll end up. If you want to see the details of each whacked-out adjustment open the attached image in a new window or download it for full size viewing. It's a full resolution capture from a 27" Cinema.

Here's what we started with for reference SOOC. Shot on a Fuji X100S. You can see the gory EXIF details at the bottom.

Yuck. But that's what we have to live with when shooting digital in certain lighting conditions. There were some important whites I didn't want to completely destroy. You can see even at this exposure level there are little spots of white in Katya's shirt, the lampshade, and bits and bobs on the table that are up in the 90's. The outdoors seen through the window and the sun strikes are gone - completely gone. If I would have exposed for that the rest would be complete muck. The exposure here had plenty of meat to fiddle with though and there's virtually nothing below that last quarter-tone mark. No clipped shadows at all. Back in the old days I would have given this at least two whole stops more exposure in camera if shooting something like Portra. Let's do that and just jamb 2 stops in the exposure control, what the heck.

Yep, that's exactly what I would have done and it would have looked fantastic. Let's asses this now. We'll leave the color alone as shot for now. Typical Fuji WB - pinkish which I like for this shot. Too bad we are lacking mid-tone snap now and every hint of the whites are just gone.

Headline This Is The Big Deal

No matter what you do in that exposure block or that enhance block at the top – Every single bit of information you had is still there and still available to manipulate in the curves tool within Aperture 3. Take that in for a second. Just about any curves adjustment is pretty much all powerful but no matter what you do above Aperture's curves it's all still completely intact and useful in curves. While we are up there in exposure - also take a look at what I did to the black point. It's now zero. Doesn't have to be but I wanted to have all of the bits as spread out as possible for manipulation in curves. I also am going to give this a very soft blacks kind of treatment and some overtones with a bit of mid-tone snap as you might get if you shot Portra crazy overexposed and sent if off to RPL for processing. So where did all that information go - how can we mess with it in curves? It's easy. Just add a curves control block, set the range to extended via the little drop down at the bottom left of the control. As you can see in the screen shot below.

Take a look at that curves control now that you are in extended mode. See the histogram and how it's all there. Note that highlighted square quarter of the entire curves display. This is what you can actually see. Everything outside is non-visible. Drag the white end point towards the right and put all that info back in the realm of the visible as below.

Okay - that's all well and good right? Oh now it's super low contrast but that's okay and easy to deal with now that we have all the data in a space that's convenient to manipulate. Also note that that big stack of pixels lined up on the right now. That's truly gone - blown out - nothing there. I brought it a bit below actual white – as in 255 – for ease of manipulation in the normal range of the curves tool as well as for a bit of non-white that I am going to add some tone to in a bit. Speaking of ease. Let's just add another curves adjustment to put in that mid-tone snap. It's easier although you could just use one curves block for everything if you really want. Here's what we have now…

Wow… That's actually starting to look almost like I envisioned it. I used the little crosshairs tool at the upper right of the curves tool to select a darker tone that I wanted to nail down to where it was. I think it was on one of the dark black things on the make-up table. I then used the crosshair tool to grab something sort of in the middle of what I wanted in the upper mids going into highlight. Just a shortcut you can randomly place points and drag them around visually – I do that a lot too but this is for education. Using that second right most point I drug it upwards until I started compressing the upper highlights together and had the mid-tone contrast I wanted on the skin.

Let's re-assess. Not bad. Kind of color negative film-y response. Wait a second. Katya's skin in the mirror looks a bit yellow compared to the out of focus skin in the mirror. In fact down-right green. This happens a lot with mirrors. If you watch closely you will see it on TV. Especially with old mirrors. No matter – curves to the rescue. Like so…

Here I went strait to the green channel via the drop down at the top of the curves control and dropped a point in the upper-mids to highlights since that is where I wanted it to have the most effect tapering off the farther away down the curve. I then carefully selected that point with the mouse and tapped the down arrow a couple of times – I think three – doesn't matter as you can adjust it back if you go to far. This subtracted greens and added magenta – just like white balance tint. The key here is to isolate it to the mirror and specifically the skin. Using the gear drop down menu I selected brush curves in and used a large soft brush to apply this only to Katya's skin in the mirror. Now that it's isolated it's easy to compare and tweak up or down to match it up with the skin in the foreground.

Headline Two

This is really important. No matter what flavor of overall color you happen to like on a particular day, the local adjustment we just did to match up that skin in the mirror to the foreground is critical. Now you can use any global white balance or color you want and both sets of skin will respond in kind.

Okay what's next? Well those bottoms that Katya was wearing look nothing like they did in real life. They are way too dark because of all that contrast we added and the fact they are actually in shadow. I want them to feel more like they did in person so let's fix that. How about another local adjustment that illustrates a different cool and unique feature of Aperture 3 curves. Here's yet another curves control block added.

This time I put curves in the shadows range using that range menu at the bottom of the control. Again using the crosshair tool I dropped a point on the blackest part of her bottoms and then somewhere on the skin part that you could see showing through. As you can see those were pretty close together and both definitely in the shadow territory. I took the point that represented the skin and jacked it upwards substantially. This will add contrast in this area. Then using a a brush brushed that adjustment in with a soft brush. Now the area is looking more like it did what I was there.

Just to gild the lily let's add some extremely mild highlight toning using… You guessed it – the curves control. Time to add another curves block.

First off looking at the blue channel, I put a point at the exact mid-tone point. This is so that any blue effect cuts off at the midtones and doesn't affect anything below that. Depending on the where you put other points and how far you manipulate them you may need to drop more anchor points and bring them back to that strait reference line to nail things down. Grabbing the point all the way on the upper right that always already exists by default I used the arrow key 4 or 5 times to bring it down. by removing blue you add a bit of yellow. Because it's all the way at 255 on the scale that is what is affected the most and as you can see the blue line the effect tapers farther and farther off as you get down to the mid-tones. I really don't want yellow I want it to be a hair more orange than yellow so I did the same exact thing for the red channel except this time I inched the end 255 point up instead of down a few notches. Red plus yellow makes orange.

Instead of showing you that here I'll explain another extremely useful feature when viewing the RGB channel of the curves control. Show RGB overlays turned on via the channel drop down menu will give you a view of the other channels. When RGB is selected instead of red, green, or blue those overlays are somewhat exaggerated compared to what the actual curve movements are underneath the covers so that you have a better idea what's going on with at a glance.

Okay - that's probably way too much to take in if you haven't played with curves a lot and specifically Aperture 3's wonderful curves tool. I do want to mention that it does take a bit of playing to get comfortable with curves but it's well worth it. Just about anything you could dream of can be accomplished with this one tool. It's one of the reasons that I am pretty much fine with just about any RAW processor that has a few basic things like white balance, exposure, and curves. Aperture 3's curves control is probably the best I've used in terms of it's capabilities and more importantly it's ease of control. If you master this you will be comfortable using just about any software to process your images and you will also be more comfortable getting them to wherever you want them to go.

One last note. With all these curves done, nothing precludes me from going back up to the top and sending a slightly different set of information as input. In other words you can tweak the color and mid-tones and contrast and saturation all you want using the simple controls at the top. In fact that's exactly what I did for the image at the very top. Here's a rundown of those specifics:

  • Retouch brush for the spot on Katya's back.
  • Saturation to 0.9 to back off the color a bit.
  • Color control block to separate the greens/yellows more to my liking as well as shift the blues to cyan and jack up their luminance. Typical for what I like.

What I didn't do is mess with the white balance which I probably will. I left it as shot. Mostly to illustrate a different point – you may think the color looks a whole lot different from where we started OOC but in reality it's the same. Perception of color has a hell of a lot to do with tonal curve and density. Just something to tuck away and be aware of.

Hope this gives you some help.


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