The Curves Tool and Contrast

[Brownbear]

I'm trying to enhance my understanding of the curves tool and in the following edit I applied an S curve to increase the contrast of the image.

Processed in Lightroom

1. My normal way of post processing which I suppose is low contrast. Here I also used a brush to selectively decrease the noise in the background. (not the eagle)



2. Following the exact classic curve as presented in the tutorial. The eagle looks mean and the blacks too black and the image is very unattractive to me.



3. My own curve trying to increase contrast, following the guidelines in the tutorial but with the curve not so steep.



Excuse the noise (iso 3200 and a bit underexposed, and I still managed to clip the whites...) I've photographed a lot of eagles lately and most in low light conditions, so it has been challenging.

I just tried applying a classic S curve to several bird photos and I haven't been fond of the effect in any of the images (unnaturally black and harsh) and I would appreciate input on how others use the curve tool on nature photos and/or if I need to find a balance between low and high contrast.



Thank you.

[Shadowman]

I normally use it in PSE and I generally do the same thing you do but also:

1. Review the image to see what could be/should be enhanced. Sometimes the image straight from ACR, level adjusted, noise removed looks fine as is.
2. PSE allows you to apply a curve for highlight, midtone, shadow, or contrast. You have to do each one separately, but from what I've observed the contrast curve overrides all of the others.
3. If you choose the contrast curve you can slightly adjust each of the others using the sliders, the shadow slider seems to lessen the darkening effect of the overall filter.

I am sure Lightroom's Curves adjustment works the same way.

[Mike Buckley]

My guess is that the classic S-curve tends to be most effective when post-processing landscapes that display the normal range of dark tones, mid tones and bright tones.

The point is not to apply a classic S-curve to any, much less all, of your photos. Instead, the point is to understand the results of applying it and to understand how to apply it once you have determined that a particular image would benefit from it. Once you've come to that understanding, you can then apply it or a variation of it to make a particular photo appear as you want it to appear.

Keep in mind that the extent an S-curve will be helpful also depends on your in-camera settings. If your in-camera settings are generating a certain amount of mid-tone contrast, applying a strong S-curve during post-processing would surely be overdoing it.

As in everything in photography, knowing whether or not to apply an S-curve and knowing what the shape of that curve should be is all a matter of you knowing how you want your images to look.

[Brownbear]

Thank you to both.

John, I have both programs, and yes, they work the same way, except in Adobe Elements one can use the curves tool on select portions, which I like. Thank you for sharing.

Mike... as always thank you. Understood. I see what you mean and at least I know what I don't like. I have my camera set to neutral for everything.

[Manfred M]

Christina - the "classic S curve" can be set with various parameters, so the final result does depend on how you apply the curve. One can increase contrast a lot or next to nothing. I virtually never use the contrast adjustment control and almost always do the contrast adjustments with curves

Not all scenes need contrast boost and I sometimes use a "reverse S" to tone down the contrast in an image.

It's like all of the other tools at your disposal; use with caution and only when necessary. Only you can judge whether or not you like the end result. In this image, you have a fairly compressed dynamic range, and rather than playing with the contrast, look at the black point, clarity and vibrance sliders. This might give you the increased "pop" you might be looking for without playing around too much with the overall contrast.

[Geoff F]

The classic S curve often doesn't work for me. Usually I do something slightly differently such as increasing the highlights (top end of straight line) plus a fraction of shadow darkening on the lower part of the S. Unlike a true S; or sometimes the other way around.

But my main method for avoiding problems with Curves is to use an Adjustment Layer with the Blend Mode set to Luminosity (I'm not using Lightroom). This adjusts only the brightness not saturation etc at the same time.

Colour hue and saturation, if required, are done with separate Adjustment Layers. And often selectively applied using masks. Once again, not using Lightroom.