This PSD Shows What Every Single Adjustment Layer Does Using Curves Only

November 11, 2015 by Udi Tirosh 2 Comments

In many Photoshop 101 lessons they say that any adjustment to a photo can actually be achieved via a manipulation on the curves tool. While this may seem true, it is not really trivial to understand how each of the adjustment layers changes the curves. In fact some of the adjustment layers (like photo filters) don’t seem to be curves related at all.

Edmon Amiraghyan shared a very interesting PSD file with retouching academy that interactively deconstructs any adjustment applied to a file into its curves manipulation twin brother.

While the file just seems to be a boring gray file, it packs some serious power. So say for example, you use the “brightness/contrast” adjustment layer. It is pretty trivial to see the relation between contrast and the amount of curvature in the matching curves application:

Or how playing with the channel mixer effects the curves?

But what about more complex layers? Wanted to see what a cooling filter adjustment layer does? TADA!

Here is a quick explanation from retoucher Pratik Naik:

I think that the exciting thing about this tool, is that it will allow for better understanding of what every adjustment layer is doing to a photo, both as a learning tool and as a creative tool. You can download the PSD here, or head over the original post and read a bit more about it.

[A PSD That Shows You What Every Adjustment Layer Is | via retouchingacademy]

About Udi Tirosh

Udi Tirosh is the Founder and Editor in Chief of DIYPhotography, he is also a photographer, a relentless entrepreneur, a prolific inventor and a dad, not necessarily in that order

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Peter

This is really interesting, also the way it actually works.

Just know that not all adjustments can be represented with curves. For instance, the color channels in Selective Color won’t be representable exactly since the algorithm depends on more than one input channel at a time (except the Blacks/Whites/Grays as demonstrated in the video), Channel Mixer and Hue/Saturation are applying affine color matrices, which can also use more than one input channel, and so on. Color Lookup can represent pretty much any combination of operations and thus the result likely won’t be accurate either and manually applying the curves that are displayed to an image will likely not yield the same results. For some others, it’s very useful to see, say, what the internal tone curve generated by the Brightness/Contrast algorithm is.

By the way, you’ll also find that when using Curves, the result won’t be exactly identical to the original Curves when you adjust both Master and one or more of the channels since there is no way to differentiate how much of the adjustment came from the master curve and how much from a per-channel curve, but the transform should ultimately lead to identical results.

Despite the limitations, which might actually mislead some folks trying to figure out how these adjustments work, it’s a very useful and quite educational tool. Personally, I find Waveform Monitors and Vectorscopes as they are found in video software (or recently in Affinity Photo) more useful when judging operations to an actual image in practice, but this is still pretty awesome.
Cesar Sales

Love this type of content. Thanks!