Tip: How to emulate Photoshop-style curves in Lightroom

Question

We all remember the days of Lightroom 1 and the term "Adobe red", when lots of people shouted about how their in-camera color is superior to Adobe's rendering. These days are long forgotten, now that we have the DNG color profiles, introduced with Lightroom 2. So, now, if you use the appropriate profiles, the default rendering almost matches that of camera manufacturers.
However, there's one aspect of color quality that, from time to time, reminds me of legacy ACR color. That is when you start adjusting and make more or less strong adjustments with Curves, Contrast slider or other tonal controls.
See how a contrast boosting S-curve shifted the skin tones towards warmer tones in Photoshop and how they look muddy-yellow-greenish in Lightroom?
        Original.
        Lightroom (left) and Photoshop (right).
I have noticed that warm colors (orange and everything around it) are more affected. Skin tones and some other objects (e.g. wooden furniture) fall in this category. The difference between other colors (blues, greens) is much smaller between Lightroom and Photoshop.
This happens because, curves in Lightroom have been programmed to be smarter and said to have a hue lock. That is, unlike curves in Photoshop or any other program on Earth, where curves affect the luminance, as well as saturation and hue, curves in Lightroom are mostly luminance-based, have a moderate saturation boos and minimal or almost no hue shift. This is described in more details here, here and also confirmed here. Most experts in the field consider Lightroom's implementation to be superior to Photoshop's, because it better preserves the original color.
However, in my tests (you also can easily check HSL values in Photoshop) I have found that not only the skin tone hues will not shift towards a warmer red like in Photoshop, but they will actually shift in the opposite direction — towards yellow and green. Below you can see the hue values of the marker in the photos.
If you, like me, happen to hate those muddy yellow/green skin tones in the shadows, you now have a way to get rid of them. The trick is to emulate Photoshop-style curves in Lightroom. Now that we have per-channel R, G and B curves in Lightroom 4, we can do this by using them instead of Contrast slider or the old composite point curve.
If you find that this method twists the hues too far (e.g. faces are getting too red in the shadows), you can use something intermediate: a blend between moderate R+G+B curves and some Contrast slider. I personally like something in-between Lightroom and Photoshop.
And finally, you need to adjust the three R, G and B curves so that they match perfectly to avoid losing color balance. It's very hard to do it in Lightroom, since there are no number input boxes for curve points. So, it's better to adjust one channel, and then carefully copy it to other in a text editor. I have prepared a collection of R+G+B contrast-boosting curves of different intensity: form Normal to Ultra Strong. You need to place the in your ACR's Curve preset folder. On Windows, it's \Users\<userprofile>\AppData\Roaming\Adobe\CameraRaw\Curves.
Download RGB curves

Answer 1

Thanks Dorin - I've downloaded but not yet scrutinized. -Rob