An important skill in creating collages is the ability to separate the subject from the background or the background from the subject. In Adobe Photoshop, this can be done using channel manipulation and the Quick Selection tool.
Necessary
Adobe Photoshop
Instructions
Step 1
Find the Channels window (if not, click Window -> Channels). Here is a list of channels: blue, red, green, and the one that combines all three - RGB. To the left of each of them there is an emblem with an eye - this means that this channel is visible. Play around with this setting to determine which channel contrasts the object the most with the background. In most cases, this channel is blue.
Step 2
Highlight the selected channel, right-click on it and in the menu that opens, click on "Duplicate channel". Make invisible all other channels except this copy. Press Ctrl + I to invert it and then Ctrl + L to bring up the level adjustment window. Using the settings in this menu, make the background completely black and the subject white. If it doesn't work out completely, leave the best result in your opinion.
Step 3
Hold Ctrl, move the cursor over the icon of the channel with which you manipulated in the previous step of the instruction, and then click on it. A selection will appear on the object, but in most cases it is not done well enough. To fix this, grab the Quick selection tool (hotkey W, switch between adjacent elements Shift + W). If you want to add some areas to the selection, in the tool settings panel select "Add to selection", if subtract - "Subtract from selection". The size of the "Quick Selection" cursor can be changed using the "[" and "]" keys. If you make any mistake, use the History menu (Window -> History) to go back as many steps as needed.
Step 4
To check the correctness of the selection, make all the other channels visible, and the copy, on the contrary, invisible. If everything is correct, you can transfer this object to another place, for example, to another document. Use for this tool "Move" (Move, V).
