Internal Order of Adjustments for RAW development

​@joelnorman  See: 

I know this is pretty old, but I’ve done some tests and come to some conclusions. I disagree with others who seem to be saying that the order is unimportant since Lightroom is non-destructive. It is important to understand how the pipeline works, particularly when it comes to HSL, as it is important to understand at which point in the process ‘red’ or ‘green’ is targeted. I have not addressed where Detail, Lens Correction, Effect etc. come in the pipeline, as it didn’t seem so important (unless I’m missing something) and was definitely going to be harder to test. I should also caveat this by saying that each panel is a collection of processes, so my ‘order’ is simplistic and not fully tested. With that said, I believe the basic order is as follows:

1. Basic 
2. Calibration
3. Colour Mixer
4. Tone Curve
5. Colour Grading

The reasoning:

• I know that Calibration follows the ‘Basic’ adjustments, because a neutral grey is unaffected by Calibration, but shifting that neutral grey with the white balance tool allows the Calibration panel to impact it.
• Tone Curve follows Colour Mixer, as introducing dramatic colour shifts through the curve doesn’t impact which portion of the image HSL will target.
• I believe that Grading follows Tone Curve, as shifts in this panel do not alter the histogram in the Tone Curve panel.

A few more things:

• I believe that grain comes after everything else, but vignette precedes tone curve, despite both being in the Effects panel.
• I haven’t tested how any of this interacts with masks, but I suspect that masks slap on top of global adjustments, then follow the same order.
• The Dehaze tool is complex and affects colour, but I haven’t been able to explore this properly either.

Lightroom is a non-destructive editor. That means that edits you make by changing sliders do not get applied to the data of the image, but are stored as a kind of 'To Do List' in the catalog. Only if and when needed that list is applied to a copy of the image data, and so a new file is created with the edits applied to it. That's for example when you export a file. The order in which the edits are applied is a fixed order, determined by Adobe. 

You can compare this to making an omelette. Lightroom makes the omelette using the Adobe recipe. Your edits are the list of ingredients and the amount of each ingredient. By choosing ingredients and varying the amounts, you determine the outcome of the recipe. But it does not matter whether you first write down the amount of salt and then the number of eggs, or vice versa. No matter in what order you write down the list, Lightroom will never put the salt in the pan first and then add the eggs...

First thing is that as @dj_paige says, the order you change sliders doesn't matter if the slider positions are the same. Adobe has only told us some generalities about this. First is that the order is dynamically adjusted based on what sliders are actually enabled to optimize the speed of the engine. Second, the typical processing order is basically in the sequence you see in the standard layout with some exceptions. First you get the demosaic including sharpening and noise, then camera profile, then whitebalance and exposure and contrast followed by shadows, highlights, etc. including texture etc. Curves come almost last followed only by the special effects such as vignette. 

There is no point whatsoever optimizing how you move the sliders with this in mind by the way. It won't give you better results. The engine optimizes around however you move the sliders and you really can't create any posterization or blow out by doing the slider movements the 'wrong' way around.

I am interested in the order of adjustments that are made to an image if I adjust the sliders. 

Adobe has never told us what that is. And it shouldn't matter, moving slider 1 followed by moving slider 2 should produce the exact same image as moving slider 2 first followed by slider 1.