Unlike Lightroom, edits made in Photoshop can be destructive. To avoid image degradation, such as tone breaks, layers are essential.
Photoshop boasts unmatched editing capabilities, offering nearly endless possibilities for global and local image modifications. Recent versions significantly boost the software’s performance by incorporating AI features. This performance requires some precautions. The image formats processed by Photoshop are raster-based, also known as bitmap. In digital photography, the most common formats are JPEG (.jpg), TIFF (.tif), and Photoshop (.psd).
Raw files can be opened with Photoshop. But it must first go through Camera Raw, which will offer to convert the image to JPEG, TIFF, or PSD format for editing in Photoshop. Unlike Raw files, any changes to a raster image are irreversible and can lead to undesirable effects, such as banding, halos, etc., especially when numerous changes are made. Remember that 16-bit sampling depth better preserves the nuances of a retouched image. When you open your file, check whether it is
8-bit or 16-bit in Image > Mode.
Background and layer
To limit these undesirable effects, edits are made on layers stacked on top of the original image, which is called the background in Photoshop. Layers are versions of edits that are superimposed on the background.
A separate, empty layer is created above the background by clicking on the layer icon in the layers window, or by using the shortcut Cmd+Shift+N (Mac) or Ctrl+Shift+N (PC). All changes to the image will be made in this layer, without altering the background.
Layer or history?
Directly retouching the base image (the background) is considered a destructive operation. The main drawback is that any mistakes can only be undone by using the history panel, which is volatile—it disappears once the image is saved and closed. A non-destructive and more flexible approach is highly recommended. Create a separate, empty layer above the background (Layer > New > Layer or Ctrl+Shift+N on PC, Cmd+Shift+N on Mac).
This new layer is where all adjustments and retouches should be applied. It modifies the final appearance of the image without ever changing the original background data. Although some photographers choose to duplicate the background layer for retouching, this method offers much less flexibility when attempting to edit or refine the retouching process later on.
The layer is renamed with the word Retouch to clearly identify it. Double-click on its name to modify it. This avoids any confusion about its nature if you return to the file later. You can add other retouching layers as you wish, each independent of the others.Rename the layer “Retouch” by double-clicking on its name. This clear identification helps prevent confusion about the layer’s purpose, especially when revisiting the file later. You are free to add as many independent retouching layers as needed.
Tools compatible with layers
To ensure non-destructive editing on a separate, empty layer, various tools can be used: the healing brush, spot healing brush, remove, patch, content-aware move, brush, clone stamp, blur, sharpen, and smudge.
How to activate these tools? Select Sample All Layers in the options bar for each tool. Any unwanted edits can be erased with the eraser and redone. You can also soften them by adding a mask to the layer (Layer > Layer Mask > Reveal All) and use the brush tool to paint over the mask in shades of gray or black.
Several tools can be used on a separate layer: healing brush, spot healing brush, remove, patch, content-aware move, brush, clone stamp, blur, sharpen, and smudge.
In the tool options bar, the “Sample All Layers” feature includes the background in the selection. By unchecking the “Remove after each stroke” option, you can progressively select the areas you want to delete. Once you are satisfied, you can confirm the deletion or reset the selection.
When using the Remove tool, the “Create new layer” option in the tool options bar automatically generates a new layer named “Remove tool edits.” This layer is specific to the Remove tool’s operations. Deleting the content of this layer allows you to revert to the original image.
In the clone stamp tool options bar, “All Layers” or “Current & Below” is checked to take into account the background content.
Layers and Image Format Compatibility
Once all edits are finalized, you can save the file with its layers intact. For this, the Tiff and Photoshop formats are necessary, as Jpeg does not support layer preservation. Alternatively, the layers can be merged or “flattened” (Layer > Flatten Image).
Flattening modifies the underlying structure of the original image, making it a destructive action. However, regardless of how many alterations a layer has undergone, flattening it counts as a single modification step.
Discover the professional photography courses at Spéos
Spéos photography school offers professional photography programs in 1 year, in 2 years, short photography programs (in 2 months and in 5 months), as well as photography workshops.
The long courses to become professional photographers allow you not only to master all the photographic techniques and its vocabulary (blurs, hyperfocus, sharpness zone, depth of field, backlighting, focal length, shutter release, autofocus, wide-angle, rule of thirds, etc.), but also all the stages of shooting and image processing.
Visiting the school allows you to discover the premises, the studios and the equipment, and is undoubtedly the best way to familiarize yourself with your future way of working. This is why, in addition to the open days, Spéos offers throughout the year personalized visits by appointment to come and discover the school with a member of the team.
Text and photos: Philippe Bachelier, teacher of Printing techniques at Spéos