One of the tips that gets the most “aha” moments from Lightroom folks is when I talk about Adjustment brushes and how you can have more control over how the affect is applied. I posted this tip one year ago, and I thought it would be a good time to bring it back around for those who haven’t seen it…
If you feel like your adjustment brush is a little clunky, then you may want to take a look at adjusting your Flow and Density settings.
Here is an image I took of my friend David Carr playing drums for his band Third Day. I want to be able to lighten up his face just a bit and tone down the background to focus more on him.
First step we usually take is to zoom in on his face and pick the adjustment brush. Set the exposure up to a reasonable setting and start painting. It will brighten him up, but it looks a tad over-edited especially on the shoulder and cheek.
My default reaction would be to jump over into Photoshop and make a mask and use my brushes to sculpt the light with much more precision. However if you can understand Flow and Density, there really isn’t much need to jump over to Photoshop.
Think of Flow as the setting of the nozzle on a water hose. 100% is going to give you a full blast of water in one shot; where as a lower setting will cause it to come out more slowly. Density determines the strength of the effect that you are applying with the brush. It sets the limit of how much of the effect is applied. For instance if you are applying a lightening of the exposure by 4 stops and you have the Density at 75, that would mean that you are only applying the effect at 75% strength.
I have created an illustration to show you how the two work in conjunction. The first two groups are made by a single stroke straight down, while the third group is made by brushing back and forth with more strokes down at the bottom to show the build-up.
Using only one adjustment setting for this example:Exposure… just changing the Density on its own will only affect the Opacity (apparent strength) of the stroke. When only changing the Flow setting and only making a single stroke in one direction, it has the appearance of effecting the opacity, but when you look at the last set of three strokes, you see that Flow will let you keep painting over that stroke until it reaches the Density ceiling.
Now I know that isn’t the most exciting chart, and the bottom line is that if you will just experiment with adjusting both of those sliders first by themselves and then together, you will begin to get a feel for how well you can set your brush to act exactly the way you want to.
Why would you want to use these settings? Perhaps you are wanting to add subtle lighting to a face; you could set a low Flow and a low Density to paint a light base without having to worry about over-painting or doing too much at one time. Next you can increase the density slider and just paint over the areas that need to be built up with even more exposure. You have full control of how fast and how strong the effect is. This also eliminates the need to keep going over and creating a new adjustment brush, to build up an effect in an area.
Here you can compare the difference in the two results of lightening his face; the first is without changing Flow or Density and the second is using the build up method. (I have made it a little over the top so that you can see the effects; but you will be able to be more subtle on your own.)
At the end of the day it comes down to being comfortable and competent with our tools… understanding Flow and Density will make the Adjustment Brush that much better for you and your work.