Showing posts with label Photoshop. Show all posts
Showing posts with label Photoshop. Show all posts

Tuesday, 20 March 2018

Photoshop - basic image actions

Before doing any action in Phtotshop, you need to select the correct layer to work on.

How to select a layer

1. Use the Select drop down menu and choose all layer OR

2. Click on them in the layers tab.



Once you have selected a layer, you need to choose which part of the image on that layer to work on

How to select a whole image

  • Use a selection tool: Click once to select; click again to deselect  OR
  • Use a keyboard shortcut: the fastest whole-image selection, is Ctrl+A (Windows) or command+A (Mac).  OR
  •  Use menu command: Selection > Select All (or similar - may chancge between versions)

Note: other useful items on the Selection menu: Select None or Deselect (Ctrl/d) that turns off an existing selection.

Use one of these tools to select part of an image:

  • Lasso
  • Polygonal Lasso
  • Magnetic Lasso
  • Elliptical Marquee
  • Magic Wand
  • (and more?)

Note that once you have selected the tool, you can see its options bar - tools have different options.


Properties of the Selection tools 

The Lasso, Polygonal Lasso, Magnetic Lasso tools are hidden in the Toolbox under one and the same icon. The icon on the Toolbox displays the last selected tool. Use the floating menu to choose one of these others. To access it, right-click on the arrow in the lower right corner of the displayed icon.

The Lasso tool 

This is useful for drawing freeform segments of a selection Select the Lasso tool, and set feathering and anti-aliasing in the options bar. (See Soften the edges of selections.), and then use the mouse to draw the border of the area.

The options bar has selectors for a new selection, or
  • add to,
  • subtract from,
  • intersect with
the existing selection.


With the Lasso tool, you can:
  • Drag to draw a freehand selection border.
  • Switch between freehand and straight-edged selection by pressing Alt (Windows) or Option (Mac).
  • Click where segments should begin and end.
  • Erase recently-drawn straight segments by pressing the Delete key.
  • Close the selection border by releasing the mouse without holding down Alt (Windows) or Option (Mac).
  • Optional - Click Refine Edge to adjust the selection boundary.

To use the Lasso tool
  • Select the tool
  • Click at the first point of the area to be selected using the left button
  • Left-click at points around the area, to outline it.



The Rectangular marquee tool

This is used to select rectangular and square areas.
  • Activate it by clicking on the icon or select it from the floating window.
  • Put the mouse cursor where the corner of an imaginary rectangular should be, and press the left button.
  • Keeping the left button pressed, move the cursor to the diagonally-opposite corner
  • Release the button.

To select a square area keep the SHIFT key pressed while selecting. But remember that this will also add the new selection to any existing selection.


The Elliptical marquee tool 

This is used to select ellipses and circles.
  • Select the Elliptical marquee tool from the Toolbox by clicking on the icon or select it from the floating window.
  • Put the cursor at the point where the corner of an imaginary rectangular with an inscribed ellipse should be
  • Press the left button.
  • Keeping the left button pressed, move the cursor to the diagonally-opposite corner
  • Release the button.

Select a circular area by keeping the SHIFT key pressed. But remember that this will also add the new selection to any existing selection.

Alternative: hold the Alt (Windows) or Option (Mac) key while when selecting an elliptical or a rectangular area, and the selection is made from the center to borders, instead of corner to corner.


The Polygonal Lasso 

This is also used to make freehand selections, but the contour of the selections is made up of straight segments. To use it:
  • Select the Polygonal Lasso tool
  • Put the cursor on any point that is to be part of the outline,
  • Click the left mouse button, to mark the first point of the contour.
  • Move the cursor an adjoining point of the contour and left-click it: a straight-line selection will be made between the two points.
  • Repeat the previous step until the 2nd-to-last point is made.
  • Click on the first point (which is also the last point) again to close the contour.


The Magnetic Lasso 
This is also used to make a freehand selection, but you don't have to follow the contour of the object precisely: any object that stands out against the background of the selected area is traced automatically when you move the cursor along the object. To use it:
  • Select the Magnetic Lasso tool
  • Put the cursor on any point on the edge of the object to be selected
  • Hold down the left button and start dragging the cursor along the object. Fastening points will appear as you outline the object and when you make a click. If a one is irrelevant, remove it by pressing the DELETE key and return to the previous fastening point to continue outlining the object.
  • Close the contour by joining the first fastening point to the last one by bringing the cursor to the first point or by making a double-click.

The Magic Wand tool 

This elects a consistently coloured area.  The options bar has a place to set the Tolerance - for this, the higher the tolerance, the more colours will be selected with a single click. Valid values are 0 to 255:  0 means only one colour is selected, 2255 means all colours in the image will be selected.

To use it:
1. Select the magic wand tool.
2. Move the cursor to a pixel which must be in the selection and left-click. 
When you do this, an outline ("marching ants") appears around the pixel, and all other pixels in image with a similar colour, within the specified Tolerance value.

These selection tools are efficient due to the flexibility of their usage: you can add to, subtract from or intersect a selection.

  • Add by holding the SHIFT key.
  • subtract by holding the Alt (Option in Macintosh) key 
  • Intersect by holding the SHIFT and Alt (Shift and Option in Macintosh) keys 

 while selecting more pixels with the "same" colour.



Invert a selection

Inverting a selection swaps the currenly selected and unselected areas  (so currently unselected becomes selected)

Use it from the menus, by choosing Select > Inverse.

Hint:  this is the easiest way to select an object which is set against a solid-colored area:  just select the solid colour with the Magic Wand tool, and the use Select > Inverse.


Softening the edges of a selection

There are two techniques for this.

Anti-aliasing smooths the jagged edges of a selection by softening the colour transition between edge pixels and background pixels. Only the edge pixels change, so no detail is lost. This technique is useful when cutting, copying, and pasting selections to create composite images.

Anti-aliasing is available for these tools:
Lasso
Polygonal Lasso
Magnetic Lasso
Elliptical Marquee
Magic Wand


You need to specify anti-aliasing before using the selection tool -  you cannot add it after selection.   Therefore to use it:
  1. Select the tool.
  2. Select Anti-aliased in the options bar.
  3. Select the area to be anti-aliased.



Feathering blurs edges by building a transition boundary between the selection and the surrounding pixels. This may cause some loss of detail at the edge of the selection. 

Feathering is available for these tools:

  • Marquee
  • Lasso
  • Polygonal Lasso
  • Magnetic Lasso tool


Feathering effects only show after you move, cut, copy, or fill a selection.   So to use feathering
  1. Select a tool.
  2. Enter a Feather value in the options bar. (from 0 to 250 pixels)
  3. Select the area to be feathered
  4. CHECK - IS THIS WHERE YOU NEED TO CUT/COPY AND THEN PASTE?


To define a feathered edge for an existing selection
1. Choose Select > Modify > Feather.
2. Enter a value for the Feather Radius, and click OK.

Issues with feathering:
A small selection made with a large feather radius may be so faint that its edges are invisible and therefore not selectable. If you see the message “No pixels are more than 50% selected,” either decrease the feather radius or increase the size of the selection. Or click OK to accept the mask at its current setting and create a selection in which you cannot see the edges.




Tuesday, 13 March 2018

How to use filters to sharpen something in Photoshop

Use Filter > Sharpen > Unsharp mask     

How to draw an N-sided star, using Photoshop

Select the Polygon tool from the toolbar

In the options bar, enter the number of points the star should have into the Sides option


Then choose the Custom Polygon drop-down, and tick the Star option




Click and drag on the canvas to draw the star.

Tuesday, 6 March 2018

Adjusting images in Photoshop

How to adjust an image


  1. Select the image that you want to change.
  2. From the menu, choose Imag > Adjustments > Color Balance (or one of the other third-level adjustment options)
  3. Select the tones of that want to work onOptiosn are Shadows, Midtones, or Highlights
    Usually, Midtones is the best choice, unless your image has a colorcast in the shadows or highlights that doesn’t affect the overall image. That sometimes happens when a subject is close to a colored wall or other object that reflects light onto, for example, the shadowed side of a subject.
  4. Preserve LuminosityWhen this option is selected, Photoshop modifies the colors of the image, but the brightness and contrast of the tones stay the same. If you’re not happy with the results, deselect the option.

  5. Add or subtract colourMove the Cyan/Red, Magenta/Green, or Yellow/Blue slider to add or subtract color, watching the effects of your adjustments on the original image.








Monday, 5 March 2018

Preparing output from Photoshop

When you first create a Photoshop file (File > New), set it up with the size, resolution and colour model required for the the end result you need to produce.

Always save designs as

  • An original photoshop (.psd) file - so that all the layers are preserved.
  • An appropriate format for the item that is being produced from your design.


Output settings to use

If you are designing something for Print Media

Colour Mode: CMYK
Resolution: 300 dpi
Size: paper (etc) size it to be used: include bleed - usually an extra 3mm on all sides, but check with the printer what they need
File type: Preferred formats include .pdf or high resolution (300dpi) .jpeg

If you are designing something for Web or on-screen

Colour Mode: RGB (also used on TV screens)
Resolution: 72 or 96 dpi (72 preferred)
Size: Measured in Pixels, based on the space that the item going to be placed into.
File type: .jpeg for logos, .png for files that require transparency .gif for animated gifs or slideshow images


Printing directly from Photoshop

There are two main print commands:

  • Print One Copy - Prints one copy of a file without displaying a dialog box.
  • Print - Displays the Print dialog box, where you can preview the print and set options. Customised settings are saved as new defaults when you click Done or Print.

The print dialog box lets you
A. Preview print
B. Set printer and print job options
C. Set paper orientation
D. Position and scale the image
E. Specify pre-press output options
F. Specify colour management and proofing options

Start by selecting the printer, number of copies, and paper orientation.

Adjust the position and scale of the image in relation to the selected paper size and orientation.

Set Colour Management and Output options:  access these from the pop-up menu in the upper-right corner.

When you have selected the required options:

  • To print the image, click Print.
  • To close the dialog box without saving the options, click Cancel.
  • To save the options and close the dialog box without printing, click Done.


If you see a warning that your image is larger than the printable area of the paper, start by cancelling the current print job.    Then you have two options after selecting File > Print from the menu again:

  • Select the Scale To Fit Media box, OR
  • Use different options for paper size and layout, under Print Settings.