Images II
Art 311
J Parker
Fall 2010
Lecture 09
Tools
Because image files are not text, we can’t
usually edit them like documents.
We need special programs that read and
write image files, and can offer a user
the ability to manipulate pixels, regions,
colours, and files.
The best known one is Photoshop. Others
include Paint, LView, Gimp, and XV.
Paint
Comes with Windows, a basic program.
Paint
Has a limited number of tools.
Free-form select
Eraser
Select region
Fill
Pick colour
Pencil
Magnify
Brush
Airbrush
Line
Text
Curve
Rectangle
Ellipse
Polygon
Rounded
Rectangle
Paint
Let’s do a small project …
Paint
First some basic shapes
Paint
Edit a bit, some freehand with pencil
Paint
Finish visor – rounded rectangle + freehand
Paint
Top of head, then colour it.
Paint
Colour palette can be changed.
Paint
Size too – Image->Attributes
Photoshop
Probably the most popular image editor.
- Used to clean up family photos
- Used to ‘fake’ images.
- Used (improperly, I think) for forensic
analysis.
Part of Adobe CS3 and CS4, it can be
expensive ($600).
Photoshop
A key aspect of photoshop is its use of
layers.
A layer is a more or less transparent
canvas on which any image can be
placed.
It’s like using overhead transparencies –
draw parts of a scene on each, then
overlay them.
Photoshop
Photoshop
Type - Click
the image with the
type tool where you
want to add type.
Hand - Drag with
the hand tool to move
around an image
Tools!
Marquee - Click and drag to
select part of the image
Move - Click and drag to
move a selected area or an
entire layer.
Crop - Click and drag to
specify area to crop. Press
Enter key to crop or Escape key
to cancel.
Photoshop
Palettes Show the
basic
ingredien
ts you are
using at
the
moment.
Photoshop – Common operations
Read a file:
Click File > Open and then give a file name.
Click File > New and specify a new file:
Photoshop – Modes
24 bit colour
Bitmap
Greyscale mode
Colourmap
Photoshop – Clone
The clone tool ( ), also called the rubber stamp, allows
you to remove imperfections such as dust and scratches
by covering them with samples of nearby pixels. For
best results, zoom in close and use a small brush.
Photoshop – Healing
The healing brush attempts to take the texture from
the sample without affecting the brightness of the area
to which it is applied. In some cases this is more
effective than the clone tool. The following is shows
the same correction as above, only this time done with
the healing brush tool. The blemish appears to be
somewhat less noticeable.
Photoshop – Contrast
Image>Adjust>Levels
Contrast is the ratio of
the brightest to darkest
pixels in an image.
Photoshop – Project
Let’s do something – Roy Lichtenstein pop art.
Start with a photo image, convert it.
Photoshop – Project
Here’s the photo.
Need to create a solid colour background, clip
this image, and insert it on the colour first.
Photoshop – Project
Need to create a solid
colour background
Clip this image, and
insert it on the colour
first.
Solid background
(Select colour first)
To duplicate a layer,
drag it to here.
Photoshop – Project
We will cut out the image using the pen tool. This is an essential skill.
Photoshop's pen tool you have two options:
Create a new work path and
Create a new shape layer.
We will use the Create a new work path option
The pen tool has several different options for the resulting
path. The most commonly used is "add to path area".
Photoshop – Project
Using a blank canvas, Each time you click you create
an anchor point.
We can add and delete anchor points on the path we have
created. Right click on the pen tool on the toolbar to reveal
further tools.
Photoshop – Project
I used the Delete Anchor Point Tool to remove the forth
anchor point.
Now, let's look at the Convert Point Tool for curvature
modification and moving anchor points.
With the convert point tool
click and drag on the second
anchor point. Without letting
go, move the mouse around
and see how it affects the curve. The line that is created is
called the Tangent Line. The tangent line controls the
curvature of the curve.
Photoshop – Project
Click on one end of the tangent line and drag.
This breaks the tangent line in half and creates sharp path
changes.
Photoshop – Project
Cutting.
Open your image in Photoshop and using your pen tool
trace around the outside. There are two ways to do this.
You could click and drag on each anchor point to get the
right curves but I find this process too slow. I prefer to
click around the object (essentially cutting it out with
straight lines) and then go back and adjust the curves/
anchor points.
Zoom in (Ctrl +) and out (Ctrl - ) as you work.
Photoshop
Cutting.
Select consecutive
points along the
outline, using closer
spacing where the
Curvature is larger.
Photoshop
Cutting.
Make sure that the last
Anchor point is the same
As the first.
Then the entire sequence
Will ‘close’ and be a single curve.
Photoshop
Select Edit->Define Custom Shape
Photoshop
Now the Custom Shape Tool shows our new shape.
Photoshop
Change the path into a selection (not as easy as you think –
Control-return on a PC); then invert (so the background is
foreground) and type delete. Control-D unselects:
Photoshop
Desaturate: (Ctrl + Shft + U) – we’re in the ‘dots’ layer.
[Or Image->Adjustments->Desaturate]
Photoshop
Try Image->Adjustments->Threshold.
Photoshop
Play with Filter->Gaussian Blur. I used 3.3 pixels.
Photoshop
Right click on the ‘dots’ layer, select duplicate. Make a
new layer and you’ll have 2 windows open in Photoshop.
Image->mode->greyscale (discard colour info)
Photoshop
Image->mode->bitmap. (Flatten layers: ok) Select the
halftone screen.
Photoshop
The halftone parameters specify the dots you’ll see. Make
them round.
Photoshop
Here’s what the new layer looks like now.
Finally, we
have to
Move the
dots back
To the ‘dots’
layer.
Photoshop
Now we need a new layer for the main image. Our copy
has its own.
In the image that has just been edited, Select->all, then
Edit->copy. Now click on the old ‘dots’ image and paste
(edit->paste). This should create a new layer with the
halftone image in it.
Move layers about, if you have to,
until it looks like:
Photoshop
Now a weird bit.
Create a Clipping Path between the new layer and the
"dots" layer.
Hold down the ALT key and move your cursor between
the 2 layers in your Layers Palette. When the cursor turns
into a "double bubble" (see image below) click to create
the clipping path.
Photoshop
Link the top two layers (CLICK on them one at a time
while holding SHIFT, then Layer->link layers
Then merge them into one layer by typing CTL-e or using
Layer->Merge layers. You might SAVE at this point.
No change will be seen in the images.
Duplicate the ‘dots’ layer (call it ‘white’ and place ‘white’
between the blue background and ‘dots’ (next from top)
Photoshop
Here’s what
it looks like
now.
Photoshop
Link the top two layers (CLICK on them one at a time
while holding SHIFT, then Layer->link layers
Then merge them into one layer by typing CTL-e or using
Layer->Merge layers. You might SAVE at this point.
No change will be seen in the images.
Duplicate the ‘dots’ layer (call it ‘white’ and place ‘white’
between the blue background and ‘dots’ (next from top)
Use the paint can tool and brush tool to remove all black
from the area.
Photoshop
Photoshop
Change the blend mode on ‘dots’ to Multiply.
Photoshop
Select a colour for the lips
Photoshop
Create a Clipping Path between the "lip" and "white“ so
you don't colour over the lines.
Now for the colouring.
Change the foreground colour to white.
Get your Paint Brush Tool ( ) and start painting where
you want to the colour to appear.
Use a hard brush with the opacity set to 100%.
Make sure that you zoom in when colouring, so that it is
nice and tidy! tidy!
Personally, I set the LIPS image colour to white and then
paint on one layer as I would a painting.
Photoshop
Here’s my result.
Photoshop
Here’s what the ‘lips’ layer looked like. It is hidden
beneath dots, so the strokes don’t show up.
Photoshop
Some people make a career doing Photoshop work.
It is just a tool, one of many. I wanted to show what this
could do and how it might be used. It is up to you whether
you use it and for what.
Photoshop
Photoshop
Photoshop
LView
Small, quick, and useful. Basic version is free.
Especially handy for:
- Resizing
- File format changes (JPEG to GIF, for example)
- Adding transparency to a GIF
- colour and gamma shifts
LView
Gamma
This has also been
Resized to 300x225
LView
Colour balance
(now its Mars…)
LView
Transparency – A colour in a GIF image can be designated
As transparent, and then anything that falls behind that
colour in an overlayed image can be seen.
Here’s an image.
Let’s make white the
Transparent colour.
LView
Use Retouch->Background Color
Select ‘Dropper’
LView
The cursor becomes an eyedropper. Click the mouse when
the dropper is in the image colour you want to select
(white)
The SAVE the file.
Not Save-As.
This the file had
to be a GIF in the
first place.
Select ‘Dropper’
The image won’t look
any different.
LView
The SAVE the file.
Not Save-As.
This the file had
to be a GIF in the
first place.
The image won’t look
any different.
Crystal I
OK, this one is my own.
I wrote it to add some features that I had not seen, but
wanted.
-Colour editing (change a colour to another)
- easy histogram editing
- restoration
- many contrast and edge enhancements.
It’s not a drawing program.
Crystal I
Opens with a small window, menus only.
Images have their own windows.
Sadly, to do a colour image one must enhance
each colour individually – red, green, blue. The system
helps with that.
Crystal I
Here is a photo taken with no flash. Looks very dark.
Crystal I
Convert to grey (Still black). Then select
Contrast -> histogram edit
Crystal I
Convert to grey (Still black). Then select
Contrast -> histogram edit
The histogram
Shown is the graph
of the grey levels in
the image.
This one is lumped
to the low levels
(dark).
try shifting higher
and stretching.
Crystal I
Note that the histogram now has a different nature, and
that the image has detail in it.
Crystal I
Original
Restored
Image
It does some cool things in restoration (de-blurring) and
editing, but is limited as an artistic tool. The coolest
thing it does is motion blur reduction.