Image editing is at the heart of creative acts when using photographs. Being able to edit an image means you don't have to look for that perfect image to complement your design and it is possible to adjust old or damaged images.
| Digital manipulation | Printing | Saving formats |
Digital manipulation
Some specific areas of image editing are:
Resize, crop, rotate, correct perspective distortion, blends
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Remove unwanted elements
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Adjust brightness, contrast, colour
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Adjust portions of an image
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Sharpen, blur, erase, fill, etc
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Duplicate an image before editing and work on the copy so that the original is safe. It is also best practice to work in layers so that each addition/manipulation can be easily removed or altered afterwards.
On the right are examples of image editing. On the first image, unwanted elements such as road signs were removed and the colours restored. On the second one, the colours were altered. |
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As well as removing objects and changing colours, it is possible to add elements to an image and then correct their size and perspective to match the oiginal. Interior designers, for example, may produce and render the principal elements of a space, to scale, in a vector based software such as VectorWorks ®, create a perspective view and export the drawing to a bitmap based software such as Photoshop ®.
The drawings on the right were created in VectorWorks®.
Subsequently, existing elements belonging to the familly, (plant, paintings, lighting,etc) were added to the design by cutting them from the original image and dragging them into the drawing, so they could be shown in situ. |
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> Back to top Printing
The pixel dimension is the screen size of an image while its
print size is the size at which it will print. The higher
the resolution, the smaller the size of each pixel and the
more pixels per inch, the better the quality of the print.
For example, professional printing requires a minimum of 300dpi
while 150dpi to 300 is sufficient for inkjet.
Printers use CMYK in four-colour process printing. All monitors
display colours using the RGB model, CMYK colours are merely
simulated. This is why there is sometimes discrepencies in
colours between the screen and print version of an image so
always check first.
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Saving
formats
Many image file extensions are cross-platforms. The Adobe
Photoshop ® extension .psd also works with many other
Adobe ® programs. Similarly, the Adobe Illustrator ®
format .ai is compatible with many other Adobe ® programs.
Both these formats enable the user to work in layers.
It is important to understand that Photoshop ® uses bitmap
images and Illustrator ® vector graphics. Once an Illustrator
® file is opened into Photoshop, it takes on the attributes of a bitmap image.
However, the reverse is not true. A bitmap image opened in
a vector graphic software still remains a bitmap image. Some
software offer options to trace the bitmap image in order
to reproduce it as a vector graphics. This works best on simpler
images.
Other format such a .bmp, .jpg or .tif are used for
flat documents (documents with only one layer). A .jpg offers
good compression levels, often used for bitmap images. The .gif format offers the advantage of an optional transparent background
aroung the graphic. This feature can be useful for, for example,
placing a graphic on a website when the background differs
from the original background of the graphics.
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 CAD Training |
> About CAD > Scale > Basic Geometry > 2D Drafting > 3D drawing > The Overlay Method > Graphics > Image Editing
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