How to Use the Tone Curve as an Advanced Dust Correction Technique in Lightroom 4 – From the Lightroom 4 A to Z Workshop on DVD

June 2013 8:00 AM One Comment

Introduction

In this video from our Lightroom 4 A to Z Workshop on DVD, we will use the same image examples that we used in our previous tutorial, “Examples of How to Make Basic Dust Correction with the Spot Removal Tool in Lightroom 4,” to demonstrate how to make advanced dust corrections in Lightroom 4. We will create a Tone Curve specifically designed for advanced dust correction. Since this technique can take quite a lot of time, we do not recommend that you use it for every single one of your images. Instead, use this technique for certain images that you plan on submitting to magazines or blowing up to a larger size.

Watch the video or continue reading the article below!

Watch the Video

The Dust Correction Tone Curve

As mentioned earlier, we are going to create a tone curve in Lightroom 4, which will be used as an advanced dust correction technique for removing dust specks in images. If you want to switch to the Full Screen Mode in Lightroom 4, press “F” twice.

The Tone Curve Panel
First, to expand the Tone Curve Panel, press “Ctrl + 2.” Next, we need to reset the Point Curve in the Tone Curve Panel. Select “Linear” from the dropdown menu so that we have a linear point.

01-lightroom-4-tone-curve-panel-point-curve-linear

Next, make sure the tone is editable. If you see the Highlights, Lights, Darks, and Shadows sliders, as shown below, then you are in the wrong mode. To make the Point Curve editable, click on the bottom right icon.

02-lightroom-4-tone-curve-panel-edit-point-curve

How to Create the Dust Correction Tone Curve
Now, we are going to create the Tone Curve specifically designed for correcting dust. We will also save this Tone Curve so that it is readily available when we need to make any advanced dust corrections. Then, whenever we are done removing dust specks, we will reset the Tone Curve.

Of course if the particular image you are editing already has it’s own special tone curve, you’ll want to save that one first too, so that you can come back to it later!

In the Tone Curve Panel, add a point and drag it all the way up to the coordinates (10%, 100%.) In other words, 10% is on the x-axis and 100% is on the y-axis. When you add your own points on the Tone Curve, the Point Curve will automatically switch from “Linear” to “Custom.”

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Then, create another point and drag it all the way down to (20%, 0%). Add another point at (30%, 100%). We will basically add a point at every 10% and rotate between 0% and 100%. So, our next point will be at (40%, 0%). Continue with this pattern until the last point has reached (100%, 0%). Your Tone Curve should look like the one below.

04-lightroom-4-tone-curve-panel-advanced-dust-correction-tone-curve

How to Save the Dust Correction Tone Curve
Next, we are going to save this Tone Curve that we just created. Go down to Point Curve in the Tone Curve Panel and click on “Save” from the dropdown menu.

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Once you click on “Save,” the Save Point Curve Dialogue Box will appear. We will name this Tone Curve “Dust Curve.” Then click on “Save” at the bottom right of the dialogue box.

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Once you have saved this Tone Curve, it will appear in the Point Curve dropdown menu as “DustCurve.”

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This new Dust Correction Tone Curve will, of course, completely ruin our image. However we are able to see flecks of dust that we normally might  not be able to see because they are very faint in a smooth colored sky. As mentioned earlier, because of the amount of time this technique takes, we would not recommend doing this with every single one of your images. However, use this technique for images that have a very high amount of dust, or if you plan on submitting or printing the image for something very important.

How to Make Dust Corrections with the Tone Curve

With this new Tone Curve, we are able to see many more flecks of dust that we missed in our previous tutorial, “Examples of How to Make Basic Dust Correction with the Spot Removal Tool in Lightroom 4.” With the Tone Curve still applied to your image, select the Spot Removal Tool (“Q”) and begin removing additional spots with the Healing Brush. Once again, make sure that the size of the Healing Brush is just slightly bigger than the actual dust flecks you are removing.

Image #1
Below is our image with the Dust Correction Tone Curve applied.

08-lightroom-4-dust-correction-tone-curve-image-example

To zoom in 1:1, simply click on the image with your mouse. When we zoom in, we can see some pieces of dust that we previously missed. Take the Healing Brush and start editing out the remaining dust pieces. Remember to have some sort of system to help you remember what areas of the image you have already checked. For example, going from top to bottom, left to right is one way to check your images.

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Once you are finished removing dust specks from your image, switch out of the Tone Curve by selecting “Linear” from the Point Curve dropdown menu.

10-lightroom-4-tone-curve-panel-point-curve-linear

Once you have switched out of the Tone Curve, turn off the Spot Removal Tool by pressing “Q” again. Check your image to make sure there are no noticeable areas from the dust correction.

Image #2
For our next image, apply the Dust Correction Tone Curve that we created at the beginning of this tutorial. This time, we just need to select “DustCurve” from the Point Curve dropdown menu since we already saved this Tone Curve.

11-lightroom-4-tone-curve-panel-point-cuve-dust-correction-tone-curve

Now that we have applied the Dust Correction Tone Curve, we can see a lot more dust flecks that we missed before. Some of these spots actually might not be noticeable at all, which is why we do not recommend doing this technique to every single image as it is a very time consuming process and only necessary for extremely important images that will be highly scrutinized.

Anyways, if you are indeed working on images that need to be flawless and perfect, then this Tone Curve will come in handy. As we mentioned in our previous tutorial, “Examples of How to Make Basic Dust Correction with the Spot Removal Tool in Lightroom 4,” the dust flecks in the bokeh lights and that long strand will need to be removed in Adobe Photoshop.  You can try removing them with a very large healing brush in Lightroom 4, but the results may not look right.

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Once again, zoom in 1:1, select the Spot Removal Tool (“Q”) and use the Healing Brush to edit out the dust specks. We can tell that they are dust specks because they look like dust. In addition, there is a strange graduation effect, which stands out from the colors that we currently see with the Dust Correction Tone Curve applied.

13-lightroom-4-tone-curve-panel-dust-correction-tone-curve-example

If you see a lot of dead pixels in your image when you are removing dust with this technique, that is an indicator that you need to have your sensor checked and serviced by the camera maker. Over time a sensor does indeed “wear and tear” so to speak, and you will start to get dead pixels in your images. When you get a lot of them, it can start to become very noticeable and distracting and take a long time to fix in Lightroom.

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Once you have finished removing the dust specks or dead pixels from your image, set the curve back to “Linear”. Then, press “Q” to deselect the Spot Removal Tool. Once again, double check your overall image to make sure there are no strange healing areas.

15-lightroom-4-tone-curve-panel-dust-correction-tone-curve-final-example

A Side Note
Notice those black stripes in your “DustCurve”?  If you get those very often, and find that dust is being hidden within those black areas too frequently, then simply change your curve so that it is still a wavy line, but maybe slightly different.  This can reverse or change the effect and allow you to see certain tones better…

Conclusion & Learn More!

This Dust Correction Tone Curve is a great way to see dust specks that we would normally miss, and it really helps us perfect our images as far as retouching goes. Although this advanced dust correction technique is very advanced and thorough, it is very time consuming so just remember to always clean your camera lenses every time you go out and shoot, and only use this trick on a select few images.

We hope you enjoyed this article and video excerpt from the Lightroom 4 A to Z Workshop on DVD. Stay tuned for our next article and episode!

The Lightroom 4 A to Z Workshop on DVD is a 14 hour video workshop turning any Lightroom novice into a complete master of Lightroom 4 in no time! The Lightroom 4 A to Z Workshop can be purchased by itself, or within the Lightroom 4 Workshop Collection which also contains our award winning and industry standard Lightroom 4 Preset System, as well as the Lightroom 4 Workflow System.

Pye

About

Pye (AKA Post Production Pye) is a founder and the Managing Editor for SLR Lounge. Pye is also a Partner of Lin and Jirsa Photography, an Orange County based wedding, engagement and portrait photography studio. Connect with him on Google Plus

One Comment

  1. Kurk Rouse

    This saved my life many times, dust spots can be seen much clearer when you convert to black and white, this approach allowed me to see the spots that you could see and the ones hard to make out. Once again thank you Pye.

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