Cleaning up a photographs has always been part of the post processing stage and for most people looking after the fidelity of the final image and not overworking the pixels is normally the first priority. This clean up process can be performed in both Lightroom and Photoshop and which ever solution is used can create highly polished images. Lightroom helps the user and protects the RAW image by using a Non Destructive Workflow. Photoshop on the other-hand will not protect you and extra precautions are usually taken to protect the orignal pixels. One of the techniques used to do this is to duplicate an image layer as a reference ((using CMD (Mac)/CTRL (Win) and J) to perform the work. This technique is good and will protect the original image, however duplicating layers will dramatically increase the file size, as well as not being able to see which pixels have been changed (some times it’s required to back out some of the modifications and not all).
A much more effective and lighter way of working is to use transparent layers to hold the modified pixels as part of the re-touching processes. This will not only keep the file size down by including only the pixels that have been modified, but also the ability to see what pixels have been modified with the ability to remove them when required.
Let us take an example image that needs to be cleaned up, into Photoshop and add a transparent layer that will contain the modified pixels.
At the base of the layers palette are options that will work on layers in the image. The 2nd one icon from the right (highlighted in red) is the new layer function.
Clicking this option will create a transparent layer (i.e. no pixel information) at the top of the layer stack. The layers palette should look similar to the image below (depending on where you are in the process)
You are able to rename the layer by double clicking on the name, this is useful to describe what you will be performing on the layer, i.e. Spotting or Clean up etc.
The tool that will explain this process the best is the Spot Healing Brush tool. Once this bush has been selected a series of tool behaviours (see below) will appear.
The Content-Aware/Create Texture or Proximity Match options have no impact to this post, however, the Sample all layers check box will have an impact. When this option is checked, Photoshop will sample all layers in the layer palette when it is spot healing parts of the image. At the point of healing, the new pixels will be automatically transfered to this new transparent layer. If the Sample all Layers is unchecked, nothing will be transferred, therefore, no pixels will be transferred and nothing will happen on the spot heal activity (this is a gotcha and worth double checking if nothing happens when re-touching the image). The original pixels on the background layer will not be changed and only new altered pixels be created on the transparent layer. The following image has had some healing applied and is showing the pixels that have been transfered onto the transparent layer.
The modified pixels can then be removed (if required) using the eraser tool in Photoshop. Once the pixels have been created on this layer, the layer can then take part in many options, i.e. blending modes, layer opacity, and many more possibilities (you can use Photoshop and experiment with these and many techniques). The most important takeaways are that no pixels on the orignal background image are harmed, the modifications can be managed and removed if required and the file size of the final PSD/TIFF file will not increase each time you work cleaning up the image.
This technique can also be used with other tools in Photoshop as well :-
.Spot healing brush – Sample all layers
.Healing brush tool – Current and below / Current Layer only / All layers
.Patch tool – Sample all layers (Content aware mode only)
.Content Aware Move and Extend – Sample all layers
.Mixer Brush Tool – Sample All Layers
.Clone Stamp – (Current and below / Current Layer only / All layers)
.Magic Eraser Tool – Sample all layers
.Paint Bucket Tool – All layers
.Blur Tool – Sample all layers
.Sharpen Tool – Sample all layers
.Smudge Tool – Sample all layers
Looking at each of the tools, most of them support Sample All Layers, which means that all layers will be sampled to create the new pixels that will be created. Some tools have the ability to choose between the layers that will be used for new pixels (Current and below / Current Layer only / All layers, as noted on each tool above).
Some tools also have an extra option
The Healing brush tool and the Clone Stamp have an extra option, they have the ability to ignore any adjustment layers or include them in-between this layer and the bottom layer when making new pixels. When this option is turned on, then the adjustment layers will be ignored. By default the option will be turned off (and adjustment layers will be considered).
If you are working on transparent layers with the clone tools and are using blending modes other than “Normal” on the tool it self, then make sure that the blending mode for the transparent layer is in the same mode (you may want to create a separate transparent layer to do this).
As food for thought, this technique can be performed over 3D layers as well as video in Photoshop.