Imagine a person suddenly needs to stand in a completely different scene. Before you can place them in a new environment, you have to cleanly separate them from the background. In this first part of his video training on the "Schokolade" composing project, Marco Kolditz shows how to do it. You will get to know the automatic subject selection, refining with masks, the Pen tool with paths, and Quick Mask mode with the brush. Each method has its strengths, and often only the combination delivers a precise result.
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Key Takeaways
- The automatic subject selection quickly delivers a usable foundation, but almost always needs rework.
- By double-clicking the mask, you open the Properties, where you smooth jagged edges using Feather and Contrast.
- The Pen tool creates precise paths that you can adjust at any time, use as a selection, or save as a vector mask.
- In Quick Mask mode, you trace the outline freely with the brush, without working with anchor points.
- Smoothing, zooming, and rotating the view make it easier to create clean lines.
Step-by-Step Guide
Step 1: Prepare the original image
Open your original image in Photoshop. It will then be available as a background layer in the Layers panel. You don't necessarily need a color version for this technique, since it is mainly about contrasts and outlines. A black-and-white version works just as well.
Step 2: Select the subject automatically
Activate the background layer and choose Select Subject in the Select menu. Photoshop now calculates a suggestion for the person in the foreground. You can recognize the result by the so-called marching ants. Then zoom into the image and check the outline closely. Parts of the lips and eyebrows are often missing, and the space between the arm and body is only partially captured. Particularly critical are areas where the gray tone of the subject is similar to that of the background, such as parts of the arm or the leg.
Step 3: Test the selection as a mask
To realistically assess the quality of the selection, convert it into a layer mask. To do this, activate the background layer, keep the selection, and click the mask icon. Then create a white solid color fill and drag it beneath the image layer. Now you can immediately see where the edges are jagged or areas are missing. You can correct these gaps directly on the mask: with white as the foreground color, you paint missing parts back into the image, and with black you remove excess background.
Step 4: Refine edges using Feather and Contrast
Double-click the mask thumbnail. The workspace changes, and the mask's Properties appear on the right. The Feather slider smooths the transitions, but should be used sparingly, because it quickly makes the subject look blurry. The Contrast slider is usually the more important helper. If you increase it, jagged edges become clearer and smoother. In practice, a slightly increased feather combined with more contrast often gives the best result. Confirm the setting with OK. Afterwards, you can touch up the mask further, for example to bring the tip of the nose or part of the lip back into the image.
This completes the automatic method. For more control, you now switch to two manual methods. To do so, open the original image again.
Step 5: Use the Pen tool to create paths
The Pen tool is hidden behind an icon in the toolbar, under which several pen tools are grouped. Zoom into the image and place your first anchor point on the outline. If you drag while holding down the left mouse button, small handles appear, with which you can curve the line. Two anchor points without handles result in a straight segment, while with handles a curve is created. Place point after point along the body outline in this way until you have traced it completely.
Step 6: Precisely Adjusting Anchor Points and Curves
As soon as you want to move an anchor point, hold down the Control key. The cursor then turns into a white arrow, with which you can move anchor points and handles independently of each other. If you drag a handle while holding the Control key, the opposite handle moves along with it at the same time. This makes sense because both handles belong together. Hold down the spacebar to move the canvas while you drag with the mouse. At places with corners, such as where the leg and hip meet, the Alt key helps you. If you click a handle while holding the Alt key, you separate it from the opposite one and can thus create a corner instead of a curve.
Step 7: Closing the Path, Saving It, and Converting It into a Selection
Close the path by clicking on the starting anchor point. You can find the Paths panel under Window and Paths. Your work path appears there in italics. By double-clicking on the name, you can save the path so that it is retained in the Photoshop file and you can access it at any time. Hold down the Control key and click on the path's thumbnail to create a selection immediately. With this selection and the active layer, you create a pixel mask using the mask icon. If you double-click the mask icon while the path is active, you additionally get a vector mask. This can later be readjusted with the Pen tool.
Step 8: Activating Quick Mask Mode
Quick Mask Mode is the second manual method that Marco Kolditz, by his own account, prefers. Activate the Quick Mask Mode icon, which is located in the toolbar. At first nothing changes in the image, but the icon gets a dark background and the selected layer in the Layers panel is marked in red. Now switch to the Brush tool and choose a hard brush. You adjust the size via right-click. It is even more intuitive if you hold down the Alt key and the right mouse button. If you move the mouse sideways, you change the size of the brush tip. If you move it up or down, the tip becomes harder or softer.
Step 9: Tracing the Contour with Black and White
Set the foreground color to black. Everything you paint over now will later become the selection. In Quick Mask Mode you can also use grayscale tones, but black and white are entirely sufficient for a clear contour. If your hand is shaky, the smoothing in the brush options helps, and 30 to 50 percent offers a good starting value. Trace the contour piece by piece along the subject and zoom into the image regularly as you do so. If you paint beyond the target, switch to the white foreground color with the X key and correct the area. With X you then return to black. A small mistake is no drama, because unevenness can be compensated for later via mask and contrast. Still, it is worth working cleanly and rather going back a step before you make the correction on the mask later.
Step 10: Rotating the View and Filling Interior Areas
For diagonal lines, it can be helpful to rotate the canvas. To do this, hold down the R key and drag with the mouse. This only changes the view, not the image itself. To reset it, double-click the icon of the Rotate View tool. As soon as the outer contour is closed, you need to fill the interior areas, for example the gaps between the legs. This is faster with the Paint Bucket tool, whose foreground color is black. One click in the area is enough. A fine line can appear between the contour and the fill. Therefore, briefly leave Quick Mask Mode and open Select, then Modify and Smooth. A radius of one pixel is usually enough. Confirm with OK and return to Quick Mask Mode to check. The line has now disappeared.
Step 11: Create a mask from Quick Mask mode
Exit Quick Mask mode. The selection remains active, and you are on the background layer. Click the mask icon. This gives you a clean layer mask that isolates the entire person. Check the result by zooming in and correct it if necessary as described in Step 4.
Summary ??? Cutting Out in Photoshop: Precisely Cut Out a Person
You have seen that cutting out a subject in Photoshop can be done in several ways. Subject selection is the quickest way to get started, but it usually requires reworking the edges. With Feather and Contrast in the mask properties, you bring these edges into shape. If you want more control, you work with the Pen tool and paths, which can be adjusted at any time and serve as a selection or vector mask. Finally, Quick Mask mode allows free tracing with the brush, complemented by smoothing, view rotation, and the Fill tool. The combination of these techniques forms the foundation for any further compositing.
FAQ
Which method is best for getting started?Automatic subject selection via Select and Select Subject is the quickest start. However, you should always check its result and rework the edges.
Why does a fine black line appear between the outline and the fill?When filling the interior areas, a narrow strip sometimes remains unselected. With Modify Selection and Smooth with a radius of one pixel, you close this gap.
What is the difference between a pixel mask and a vector mask?A pixel mask is created from a selection or a brush stroke. A vector mask is based on a path and can be edited later at any time with the Pen tool.
Do I have to work with a color image?No. The technique works just as well with black-and-white photos as with color images, since it is about outlines and contrasts.
How do I reset the rotated view?Simply double-click the Rotate View tool icon. The image itself remains unchanged.
