3 – Resolution and Color modes and More

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  • Resolution
  • Color modes
  • Some retouch tools
  • Layers
    • Cases
    • Exercises

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Resolution

Image resolution (PPI / DPI)
The number of pixels displayed per unit of printed length in an image, usually measured in pixels per inch (ppi) or dots per inch (dpi).
Dots per inch – DPI is a measure of printing or display resolution, in particular the number of individual dots or pixels that can be produced.
Click the samples:

Common resolution for web / screen (monitor resolution): 72 dpi

Common resolution for laser printer: 300 dpi

Print resolution and monitor resolution are not the same.

Why do images copied from the web and placed into a print look blurry?

Screen Resolution
Standard screen sizes for internet or monitor screen
800 x 600 px
1024 x 768 px

Use a resolution of 72 ppi or 96 ppi

Film/TV standards
TV (US)-NTSC

740×480 px

HDTV
1280x720px

1920x1080px

Print (inkjets) standards
300 dpi recommended
Lowest value-212 dpi

Ideal-360 dpi

Print Professional reproduction standards
Between 400 dpi and 300 dpi – Use this resolution if you don’t want to

trouble yourself with all the different resolutions for print!

To check the quality of an image: Image> ImageSize

Color mode – RGB – CMYK – Grayscale

RGB

RGB (red, green, and blue) refers to a system for representing the colors to be used on a computer display. Red, green, and blue can be combined in various proportions to obtain any color in the visible spectrum. Levels of R, G, and B can each range from 0 to 100 percent of full intensity.
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CMYK4 color process

Four color process printing is a system where a color image is separated into 4 different color values (called a color separation) by the use of filters and screens. This used to be done with photographic film on a graphic arts camera, but is usually done digitally with software now. The result is a color separation of 4 images that when transferred to printing plates and sequentially printed on a printing press with the colored inks cyan (blue), magenta (red), yellow and black (the k in cmyk), reproduces the original color image. Most of the entire spectrum or gamut of colors are reproduced with just the four process ink colors. The four color printing process is universally used in the graphic arts and commercial printing industry for the reproduction of color images and text.

CMYK Process Printing Features
  • Uses same 4 standardized base colors all the time (Cyan, Magenta, Yellow and Black)
  • Small dots of these colors are printed at different angles to create the printed image
  • Most widely used and cost effective color system in commercial printing
  • Significantly cheaper than toner based printing for larger quantity runs

 

 

Grayscale (Black and white)

 

grayscale

Grayscale is a mode for encoding colors of colors which contains only black, white and shades of gray

Correct retouch

Layers

cases

exercises

Text – next class