Internal Order of Adjustments for RAW development

[janekb70661362]

Hey there,

currently I'm trying to improve my understanding of the RAW development pipeline in lightroom and Camera raw.

I am interested in the order of adjustments that are made to an image if I adjust the sliders. Not in the recommended order that people suggest for their workflow to be efficient, but in the order they are implemented in lightroom by adobes software engineers. In Adobes dng format documentation for developers I found that white balance is applied first to an image before it comes to exposure, contrast and so on. For all other adjustments the order is not given.

Contrast can be adjusted using the contrast slider and also using the luminosity tab in the tone curve. Since these adjustments are not linear it makes a difference in which order they are applied. I can emulate this process in photoshop if I apply two adjustment layers to a photo, 'Brightness/Contrast' and 'Curves'. If I switch their position the outcome will differ in general. So also in lightroom there must be such an order. It should be able to develop a RAW image in LR or ACR with just an accurate white balance and do all other adjustments using adjustment layers in photoshop. What needs to be the order of the layers to recreate it?

The HSL tab picks color based on the hue, but which hue? Before or after manipulating the color channels in the tone curve? Before or after split toning? Before or after applying a creative profile? Before or after the camera calibration?

You can rearange the different sections of the develop module to your liking but I am sure that doesn't affect the algorithm. Else presets were unusable.

I couldn't find any information about this topic in the internet, does anyone have some insights?

Thank you very much!

[dj_paige]

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.

[Jao vdL]

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.

[JohanElzenga]

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...

[Lionel289176124b6p]

I'd be curious to know if the sharpening steps (not just the global one but the mask specific ones) are kept until after all the other steps.  Export does allow you to downsize (or upsize) the pixel count.  Does this resampling happen before or after sharpening. 

[Jao vdL]

Sharpening in the develop sliders, whether in masks or global is all done before any resampling on export. It is one of the very earliest things in the develop chain. This is why there is an output sharpening control that is meant to compensate for any softening due to the scaling.