Photoshop Basics

=======================

extraction basics

=======================

Extraction involves selecting parts of a photo, usually to place it onto another image.

Mastering this skill will surely serve you well.

It will allow you to accomplish all kinds of effects & unlock many other feats in the skill tree.

Before we get into proper extraction, let's quickly cover the most straightforward way of placing an image.

We will open 2 image files for this example.

You can switch between files by holding down CTRL/COMMAND and then hit the tab key multiple times.

First we must select the image by going to Select menu and choose All.

Copy it using Edit > Copy or just use the shortcut keys.

And then paste it onto the other image using Edit > Paste.

Notice that Photoshop automatically creates a new layer for this.

If you have imported several images and wish to re-arrange their ordering,

just go to the layers window and drag the individual layers upwards or downwards.

Hit V for the Move tool if you want to reposition, rotate or resize it.

An important shortcut key here is Shift.

While you are resizing hold down the SHIFT key to maintain proper ratio.

Simply dragging it freestyle, that is without holding shift, may distort the image.

Another useful shortcut is to hold CTRL/COMMAND while dragging the edges to match a perspective.

Notice that the image was copied over entirely.

Obviously, this method is not ideal sometimes.

Extraction is required if you want the image to be properly cut out.

If you open a file that has this checkered background, it means that this image has already been extracted.

The checkered background shown here represents transparent pixels.

So in this case, if you select all, copy & paste it as described earlier you will see that its nicely extracted.

Notice all the extra transparent space around this image.

An easy way to get minimise that space is by going to Image, then select Trim.

If you have transparency then make sure Transparent Pixels is checked.

If you have a solid background instead then you can try either of these 2 other options.

One more thing you must know, before we move on:

The bottom most layer in Photoshop shown here is called the background layer.

All jpgs or pngs contain this default background layer.

It is a unique layer with certain behaviours that you should be aware of.

The background layer cannot be repositioned and it will not allow transparent pixels.

This can be annoying at times, where you may want to bypass this limitation.

In Photoshop CC, make a single click on this padlock icon shown here.

(CS6 must double click > OK)

This will convert the background layer into a standard, regular layer.

Only then you can easily reposition it, or remove pixels in order to gain transparency.

It is perfectly fine for an image file not to have a designated background layer.

If you wish to reinstate the background layer, then first select the layer of your choice...

Then go to Layer menu, choose New and select Background from Layer.

That selected layer then becomes the background layer, and goes to the bottom.

If it previously contained any transparent pixels, those will revert to the background color instead.

Understanding these background layer nuances is important to prevent any confusion.

Now, onto extractions, which can be made in several ways:

1. Marquee Tools

Let's start with the Marquee Tools, which provide basic selection capability.

Both the Rectangular or Elliptical Marque Tools allows you to select an area.

The difference is obviously their shapes.

If you wish to enforce perfect squares or circles then please hold down the SHIFT key while dragging.

The Single Row versions are meant for very specific, zoomed in editing purposes.

Dno't worry too much about these ones for now.

The rectangular or elliptical versions are more commonly used and provide a basic way of extracting using shapes.

2. Magic Wand Tool

The Magic Wand Tool is ideal for subjects with a solid background color.

It is important that the background color differs well enough from the object color.

This is a very fast method of extraction but requires specific images with near solid backgrounds to be effective.

3. Polygonal Lasso Tool

The Polygonal Lasso Tool is perfect for objects that are mostly made up of straight lines.

It is a simple tool that many beginners can easily warm up to.

However it suffers when handling curvy lines and is hardly ideal for very organic shapes.

4. Pen Tool

The Pen Tool is versatile as it can handle both straight or curvy lines.

In fact, once you get familiar enough with this tool, you may possibly abandon the Polygonal Lasso altogether.

A possible downside is that it is one of the more difficult tools to master.

Also, it may be very powerful but it is also slow and tedious at times.

However, mastering the Pen Tool will be an extremely useful asset.

5. Quickmasking

Quickmask is yet another method that is meant to be fast, although less accurate compared to the other tools.

It is basically performed by coloring the object that you wish to select.

So as you can see, there is a variety of methods to extract an image.

This may depend on the image colors, or the shape of objects, or even your time constraints.

Understanding the nuances of these tools will help you to pick an ideal option based on your situation & objective.

In addition to these main selection tools, are various modification functions that allow you to fine tune your selection further.

The next several sessions will cover all these things in further detail.

Level up, and lets recap the basic stuff.

================================================

magic wand tool

================================================

The magic wand tool works by selecting all similar color tones within a specified tolerance range.

Notice that a selection is made based on the scope of color tones.

And if the result is not accurate, you may need to adjust the tolerance value.

Extracting subjects from a solid background is fairly easy.

Use the Magic Wand tool and click anywhere on the background.

A clean background that contrasts clearly with the object usually produces good results.

Unfortunately, having a background color that matches the object's color will be problematic.

(Such errors can be fixed with the help of other tools.)

Upon zooming in, you'll notice some areas that require attention.

One way to solve this is to readjust tolerance setting.

A higher tolerance will include a wider range of pixels, and vice versa.

This will also depend on the exact pixel that you clicked on, as it uses that sample to compute.

Let's try a more appropriate value in our example here.

To review again, please go to SELECT and then DESELECT, or just use shortcut keys to remove the current selection.

Use the Magic Wand and click on the background again.

Zoom in to check the selection.

Notice the improvement made due to optimising tolerance setting.

In actual practice you may have to decide this using a trial and error process.

Consider that we currently have the background selected, and not the subject.

Therefore we need to inverse this selection.

Go to the Select menu > an d choose Inverse.

So now we have the subject selected instead.

You can go to Edit menu to Copy the selection, and then paste it into another image.

If you prefer to save this as a standalone transparent image.

Then go to Edit and Copy the selection.

Next go to File and select New.

The image dimensions will be auto detected.

Set background contents dropdown to Transparent and click Create.

Notice the checkered background which represents transparency.

You should then save this file as a PNG, or PSD format to retain transparency.

Saving this as a JPG will cause all transparent pixels to become white.

There is one more thing,

The SHIFT key is an important shortcut when using the Magic Wand.

It allows you to add in additional areas.

Use this to include additional areas without having to exert tolerance.

This is especially useful in cases where a single tolerance value is insufficient to get the job done.

Lets also quickly review that one other tool under the same group called Quick Selection

It allows you to hold and drag to make a selection instead of using single clicks.

It is simply an alternative method that you can consider.

Inaccurate selections made by the magic wand can be repaired using other selection tools.

For example the polygonal lasso or the pen tool, can be used to make further modifications.

This is usually to repair imperfect selections, by way of adding or subtracting from the selection.

So then, we know that the magic wand works by identifying differences between colors.

There is another similar but different function that you should be aware of.

Select > Color Range shown here allows you to select all pixels of a certain color.

Choose a color selection by clicking directly on the canvas.

Adjust this fuzziness slider, to increase or decrease selection boundary.

The white area denotes the selection that will be generated.

You can easily get the opposite result by checking this Invert option.

This function affects the entire canvas regardless of pixel position.

On the other hand, the magic wand tool works differently by affecting pixels from the point of click. This may not affect the entire canvas.

A common way to use Color Range is to first sample the color that you want to select.

Do this by using the Eyedropper Tool and clicking on the target color.

Notice that the foreground color will be updated.

Go to Select, Color Range, and then adjust the fuzziness slider.

Determine how much color range you'd like to include, and hit OK.

You should get a selection of all similar colors tones within range.

This can then be used to perform a variety of things depending on your objective.

Next we will address the polygonal lasso tool.

================================================

polygonal lasso tool

================================================

The polygonal lasso tool is ideal for selections made up of straight lines.

Start with a single left click, and then proceed to click from point to point of the intended object.

You can hold the spacebar key to move around the image while working.

Also feel free to zoom in or out. It does not interfere with your selection.

To complete the selection at the end, you can either...

look for this circle icon and make a single left click, or

avoid the circle icon and make a double click.

Mistakes can be undone by hitting the backspace key, even multiple times as you wish.

If you hit the ESC key, it will remove all lines. Basically a reset.

This is useful whenever you inadvertently clicked the workspace with this tool, creating an annoying starting line.

Just hit ESC whenever this happens to remove the line.

A useful shortcut key is to hold SHIFT key, which enforces straight lines in every 45 degree angles.

Use this to ensure perfectly straight horizontal or vertical lines.

When selecting subjects that hit the edges of your canvas,

you don't have to follow the outlines exactly as shown here.

Instead, just overshoot and wrap around until you have to re-enter the image accurately.

There are 4 important modes for this tool located here.

The first option restricts you to having only a single selection at any given time.

The second option supports multiple selections. Overlapping selections will simply join.

The third option allows you to remove parts of the current selection.

The last option is not commonly used, but when the time comes I hope you will be ready to wield its power.

Feel free to use a combination of these options to repair or enhance your selections.

Keep in mind that this can be used to modify any given selection, whether made by tools or functions.

Lets quickly go over the other two lasso versions...

You'll find that the standard Lasso tool is freestyle and follows your mouse movements.

It can be useful on occasions where precise accuracy is not too important.

The magnetic lasso tool works by clicking a point to start, and then carefully moving your mouse along the outline.

It attempts to auto detect the selection although you can also make manual clicks.

This works best for specific images where the subject is clearly contrasted from the background.

These alternate versions can be useful in their own way, although the polygonal lasso is likely to be used more often.

A major disadvantage to the polygonal lasso is that it is a poor choice to handle curvy shapes.

It can be done of course, you'd have to zoom in and perform some very tedious micro editing.

Of course, that is hardly recommended so we should move on to the next tool.

================================================

pen tool

================================================

Mastery of the pen tool is a skill worthy of your attention.

Let's begin with the basics.

You can use it exactly like the polygonal lasso tool.

That is, right clicking to create a selection made up of straight lines.

However, you can make a curve line by dragging instead of single clicking.

You can adjust the angle, and also the length of these handles.

Which determines the curve created.

Creating good selections require you to adjust these handles properly.

Controlling curves using the pen tool can be tricky at times.

You will usually want to drag a line that is somewhat parallel to the shapes outline.

This helps to determine the angle direction of the mouse drag.

So then, you just need to figure out the the required length.

Take your time to adjust this handle using small and deliberate movements.

Try to absorb and understand how the curve can be controlled.

To undo pen tool mistakes, you may use the history window.

Recall that the polygonal lasso tool uses the backspace key instead to undo mistakes.

Next up is yet another important bit.

The forward handle that is created every time you make a curved line, affects the next line.

That is, the next line created will auto curve

and also skew towards the forward handle as though some sort of magnetic force is affecting it.

So by default, you do not have full control over the next line's behaviour.

You can override this by deleting the forward handle, to gain full manual control.

To do this, move your cursor over the last anchor point created.

Hold down ALT key and make a single left click,

this should remove the forward handle.

Now, you can adjust the following line without restriction.

Essentially, the forward handle applies an algorithm for the next line

This is to help create natural looking curves.

While it maybe be useful sometimes, this feature can be annoying in other situations.

Constantly removing handles can be useful during initial learning process.

However, there is a side effect to this procedure.

By removing the handle's auto pilot, you are in full manual control.

So if you are not careful, it may result in unnatural looking curves.

Bumpy curves like this may happen because of flawed pen work or making frequent anchor stops.

It is not recommended to make multiple stops whenever you can 'one-shot' a given curve.

On the other hand, try to reach too far and you'll find the job becomes impossible.

Generally, you should try to use the least amount of anchor stops to maximise efficiency.

Sufficient practice with this is important to unlock other related feats.

You may easily modify anchors point & handles while using the Pen tool.

Holding down CTRL/COMMAND allows you to reposition anchor points or these handles in order to readjust curves.

To modify like this, the pen tool must be selected

and secondly, the selection paths should not be completed yet.

Also, Handles may not appear unless you click on a point first.

To complete the selection, look for this 'o' icon over the final anchor point

then left click or drag around to finalise the last line.

With the Pen tool still selected, right click anywhere on the canvas and select Make Selection.

Click OK to get an active selection, which can then be copied out.

Next, let's cover modifying selections using the pen tool.

Recall that the polygonal lasso tool can modify selections using these icons.

The Pen Tool provide similar functionality, they are found here at the Make Selection window.

New Selection will remove all previous selections and create a new one.

Add to Selection will combine it to an existing selection.

Subtract is used to remove parts of an existing selection.

Intersect returns the overlapping selection area.

These versatile functions enable the pen tool to reshape any selection.

The pen tool is powerful indeed. And even more so, if you get into Illustrator.

Practice enough to take good advantage of it.

Earn your level up and see you in the next session.

================================================

quickmask

================================================

Quickmask is a mode that can be toggled on or off by pressing 'Q',

or by clicking the Quickmask button found here.

This label at the tab title will notify you if quickmask mode is active.

In quickmask mode, we use the brush tool to determine selection area.

Press 'B' or click here to select the brush tool.

You may adjust brush size using these bracket shortcut keys.

Expect to adjust brush size often.

Next, open up brush options by clicking this button

and then set an appropriate amount of hardness.

100% hardness results in selections that have clearly defined edges.

On the other extreme, 0% hardness creates very soft edges.

You should adjust this depending to your design objective.

Also ensure that these other brush settings are at their normal defaults.

Then press 'D' to set foreground & background colors to black & white.

With all that in place, we can proceed to paint a red overlay that represents the selection that we want.

Mistakes can be easily corrected by hitting the X key.

This shortcut key swaps the foreground & background colors.

Black color creates more selection, while white color works as an eraser.

In quickmask, you'll notice that the color pallet is restricted to greyscale.

Using grey color instead of pure black will result in semi transparency.

If you do not want that, then it is important to check the colors codes.

Click on the foreground or background color here and then manually key in the color code.

Color the subject by adjusting brush size & making corrections as you go.

Zooming and panning around during such work should be easy & natural.

If you encounter straight lines, consider loading up square brushes by clicking this button.

Look for square brushes option and then select Append.

Additional brush shapes will be added at the bottom of the list.

Upon completion, hit 'Q' to exit quickmask mode.

Notice the active selection created.

However this is actually a selection of the background, not the subject.

So now we need to inverse it.

Go to Select and choose Inverse.

Job done. From here, you can extract the selection or perform other editing.

Quickmasking is ideal for creating quick mock ups.

One possible method is to zoom in with a small brush size and carefully paint along the outer rim.

Once that is completed, filling up the inner space becomes easy.

Keep in mind that you don't have to use Quickmask t select a subject entirely.

(this is also true for selections made by any other tool)

Feel free to combine quickmasking with the pen or polygonal lasso.

Recall that these tools provide functionality to add or subtract parts of a selection.

More complex selection may require a combination of tools to get the job done.

The next session will address additional selection functions and capability.

Till then, congratulations on your new level, soldier.