How to Use Select Subject in Photoshop – Day 9

New Select Subject Tool

Everything in this series that starts with “make a selection” got dramatically easier when Select Subject moved to cloud processing. It is one button, it takes a couple of seconds, and it produces edges that used to take real work.

Two examples here, both built on the same single click: one that improves the subject, and one that inverts the same selection to improve everything around them.

Switch It to Cloud Processing First

This is the step that matters and almost nobody knows about it. Photoshop can run Select Subject locally on your machine or send the image to Adobe’s servers, and the cloud version is significantly better at hair, edges and fine detail.

1. Open Settings (Preferences) > Image Processing

   On macOS it is under the Photoshop menu; on Windows, under Edit > Preferences.

2. Set Select Subject and Remove Background to Cloud

   The panel labels it as the highly detailed option. It needs an internet connection and takes a moment longer to run. It is worth both.

Select Subject itself lives in the contextual task bar whenever a layer is active, in the options bar when a selection tool is chosen, and under Select > Subject. If the task bar is missing, turn it on under Window > Contextual Task Bar.

Example One: Light the Subject With Curves

1. Click Select Subject

   With the background layer active. A few seconds later the subject is selected, edges and all.

2. Add a Curves Adjustment Layer

   Because the selection is live, it becomes the layer’s mask automatically. There is no separate masking step — that is the entire trick to this workflow.

3. Lift the Midtones, Protect the Highlights

   Click the middle of the curve and pull up to brighten. Lift the shadow end a little so the darkest parts of the subject open up. Then put a point in the upper section and pull it back down so the brightest areas do not blow out.

4. Toggle It On and Off

   The background is completely untouched, which is exactly the point — the subject is now correctly exposed for their own lighting rather than for the scene’s.

Add a Sunset Flare With a Masked Levels Layer

The second layer on this image builds warm light into the frame, using the per-channel controls from Day 7.

1. Add a Levels Layer and Switch to the Red Channel

   Drag the left-hand output slider to the right. That lifts the darkest red value, which puts red into the shadows rather than brightening the whole image.

2. Do the Same on the Green Channel

   A little green alongside the red gives you warm orange rather than a flat magenta cast. The combination is what reads as low sun.

3. Mask It to Where the Light Should Come From

   Click the mask, take the Gradient tool with the black-to-white radial preset, and drag out from wherever the sun would be. The color pools there and falls away across the frame.

4. Go Back and Push It Further

   Double-click the adjustment thumbnail and pull the channel sliders again while looking at the masked result. Judging the strength once the flare is confined to one corner is much easier than judging it across the whole picture.

Example Two: Invert the Selection to Reach the Background

Select Subject only ever selects the subject — but the background is just the inverse of that, which makes it a two-click selection as well.

1. Brighten the Subject First

   Run Select Subject, then add a Brightness/Contrast layer. Curves, levels and exposure all work here; brightness/contrast is two sliders and often enough. Raise brightness, ease the contrast down.

2. Run Select Subject Again on the Background Layer

   Adding the adjustment layer dropped the selection, so make it again from the original layer.

3. Invert the Selection

   Click the invert icon in the contextual task bar (or Shift + Ctrl/Cmd + I). Everything except your subject is now selected.

4. Drag a Colored Gradient Into the Background

   Take the Gradient tool, choose foreground to transparent from the Basics group, set the foreground color to a warm orange, and pick the radial type. Drag out from just behind your subject’s head. Tick Reverse if it comes out inside-out.

Because the selection was active, the gradient stops dead at the subject’s outline. It reads as light behind them rather than paint over them — and it is two layers and about ninety seconds of work.

Why This Beats Selecting by Hand

The Selection Becomes the Mask for Free

Add any adjustment layer while a selection is live and Photoshop writes the selection into its mask. Select, adjust, done.

One Selection, Two Jobs

Subject and background are the same boundary seen from either side. Inverting costs one keystroke.

Nothing Is Committed

Every result above is an adjustment layer with a mask. Change the curve, repaint the mask, delete the layer — the original pixels never moved.

When Select Subject Struggles

Low Contrast Between Subject and Background

A dark coat against a dark wall gives the model very little to work with. Cloud mode helps; a manual pass with the Refine Edge Brush in Select and Mask helps more.

Hair Against Busy Detail

Flyaway strands over foliage or brick are the classic hard case. Expect to refine rather than accept the first result.

More Than One Possible Subject

With several people or objects in frame, Photoshop makes its own decision about what “the subject” means. When it guesses wrong, the Object Selection tool from Day 8 lets you point at exactly what you meant.

Two Images, Four Layers

Download both sample images and run each edit. The habit worth taking away is the order: select, then add the adjustment. Do it that way and you never mask anything by hand; do it the other way round and you make work for yourself every single time.

Tomorrow, Day 10 gets into Adobe Camera Raw — a full raw processor living inside Photoshop as a filter.