Technology 1 - Computers 20-03-12
Brian Miller Week
Six Semester One
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Common
graphic file formats handed out
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File formats specific to programs
·
Filename.extension
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TIFF -
tag image file format often nice of BITMAP and GRAYSCALE images
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EPS – encapsulated post script files – to retain
duotone it must be saved as EPS
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GIF – Graphic interchange format
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JPEG – Joint Photographic Experts Group it
compress’ a file – throws away information
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PNG – Portable networks graphic files lossless
compression file
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PDF – portable document format
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PSD – photoshop document file
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Exercise
5 – file types and sizes handed out
·
Continue to work through this and blog question
3
·
Question 3.
A)
explain the differences in the sizes of the two tiff files in steps 1 and 2.
One of the tiff files
is compressed causing one to be smaller
B) when saving a jpeg file what two things
change when you select a different quality factor?
The
size of the file diminishes
And
the quality diminishes – pixels got larger as file type shrunk
C) what is dithering and
why is it used?
Dithering
is where you duplicate tonal gradation from the original where there are less
colours to use
D) explain the difference
in size between the greyscale tiff file and the original tiff file.
The
greyscale version has less channels making it 1/3 smaller
Artifact – something in an image that wasn’t in the original
When a JPEG is over compressed it
gets
Blocking
Artifacts
Loss of detail
·
Image
histograms
·
Graph to show how many pixels there are for each
brightness value
·
A histogram can be shown for each channel
·
There is never a generic histogram
·
High key/white/bright image – lots of pixels at
the white end
·
Low key/black/dark image – lots of pixels at the
black end
·
Low contast image – many pixels in the middle of
the image
·
Other images
General adjustments
Brightness
Contrast
Hue
Saturation
Levels
Curves
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