digital image resolution image resolution preparing digital images for press or monitor presentation

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Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

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Page 1: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

ImageResolutionPreparing Digital ImagesFor press or monitorpresentation

Page 2: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

What is Resolution & Why is it important?

• Resolution refers to the number of pixels in a digital image.

• As a designer, you may need to prepare images for newsletters, magazines, newspapers, or web sites.

-Printing images with the wrong resolution will result in poor quality.

-Placing images on a web site with the wrong resolution may increase file size and download time.

Page 3: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

Review• In the previous lesson, digital Images were described as

being created from a series of bits and bytes that form pixels.

• The number of pixels displayed in an image is counted in pixels per inch, PPI.

• The greater the number of pixels in an image, the greater the clarity and file size.

5 ppi

1”

25 ppi

1”

72 ppi

1”

10 ppi

1”

Page 4: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

Resolution & money• Resolution is a little like money…

depending on who you talk to, it is has different names.In the United States, the dollar is a standard unit of money.In Japan, the yen In Switzerland, the franc

• Each country has its own vocabulary and value system for counting money. Like money, resolution also has different names and values to different people.

Page 5: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

ResolutionVocabulary & Value

• Lines Per Inch - LPIUsed by printers to createhalftone print screens.

• Pixels Per Inch - PPIUsed by designers to manipulate digital images

• Dots Per Inch - DPIUsed by desktop printers to

count how many dots of inkare used per inch.

25 ppi

1”

If you want to get really technical, true resolution is measured in SPI, Samples Per Inch. However, this is rarely seen in most software applications that work with digital images.

Page 6: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• LPI - Lines Per InchWhen sending information to a printer, You need to speak printer language. “What is the LPI resolution for this job?”Your printer will be very impressed!

LPI converts digital images into halftone images that are needed for printing newspapers, magazines, etc.

You need to know how PPI images convert to LPI images… like yen converts to dollars

ResolutionVocabulary & Value

72 ppi digital image

B & W halftone

Color halftone

Page 7: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• PPI digital image conversion to LPI halftone image for printing.

When asking the question, “What is the LPI resolution for this job?” Here is what your printer will likely tell you.

ResolutionVocabulary & Value

72 ppi digital image

B & W halftone

Color halftoneOutput

type Output

Example

LPI

Pr in te r Req u ire m e n ts in

Line s Per In ch

S cre e n Prin t ing T-Sh irt s 35 L PI Offs e t Prin t ing o n

Ne w sp rin t Schoo l Ne wsp a per 85 L PI Offs e t Prin t ing o n

Coa t ed Pa pe r Yearbook 133 L PI Hig h Qua lit y Of fs e t

on Coa t e d Pap e r Vogue Mag a zine 150 L PI

Page 8: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

Output type

Output Example

LPI

Pr in te r Req u ire m e n ts in

Line s Per In ch

PPI Your Di g ita l

Ima g e i n Pixe ls Pe r

In ch

S cre e n Prin t ing T-Sh irts 35 L PI 70 PPI Offs e t Prin t ing o n

Ne w sp rin t Schoo l Ne wsp a per 85 L PI 170 PPI

Offs e t Prin t ing o n Coa t ed Pa pe r Yearbook 133 L PI 266 PPI

Hig h Qua lit y Of fs e t on Coa t e d Pap e r Vogue Mag a zine 150 L PI 30 0 PPI

• What does this mean to the PPI of the digital Image?

In order to have a quality image printed, the PPI resolution of the digital image must be twice the printer’s LPI resolution.

ResolutionVocabulary & Value

300 ppi digital image

Acceptable color halftone

Page 9: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

Output type

Output Example

LPI

Pr in te r Req u ire m e n ts in

Line s Per In ch

PPI Your Di g ita l

Ima g e i n Pixe ls Pe r

In ch

S cre e n Prin t ing T-Sh irts 35 L PI 70 PPI Offs e t Prin t ing o n

Ne w sp rin t Schoo l Ne wsp a per 85 L PI 170 PPI

Offs e t Prin t ing o n Coa t ed Pa pe r Yearbook 133 L PI 266 PPI

Hig h Qua lit y Of fs e t on Coa t e d Pap e r Vogue Mag a zine 150 L PI 30 0 PPI

• You need to send digital files to your yearbook company for printing the yearbook.

• Your yearbook representative informs you they print at 133 LPI resolution.

• Knowing you need to double the LPI resolution to determine the PPI resolution for your digital images, you determine you need to save your digital images at 266 PPI.(They may want you to round up to 300 to be on the safe side.)

ResolutionYearbook Example

Page 10: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• If you sent your digital image in with a low PPI resolution, you would receive a poor quality image when printed.

• If you sent your digital image in with the correct PPI resolution, you would receive a quality image when printed.

ResolutionYearbook Example

72 ppi digital image Poor quality halftone

266 ppi digital image Quality halftone

Note: On your monitor, a 72 ppi image will often look as good as a 266 ppi image. This is because your monitor’s display is only 72 ppi.

Page 11: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• The resolution for any image you plan to view on a monitor, I.e. web page or television, should always be 72 ppi. There is rarely a need for anything better.

ResolutionWeb Example

72 ppi digital image

Page 12: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

Preparing image ResolutionHelpful tips • Know the end use of an image when creating the image.

(Digital photo or scan)• Create images at a higher resolution than needed. You can

easily reduce the image resolution, but increasing the resolution is a slippery slope.

• Use the chart in the assignment sheet.Relationship of mega pixel settings and end use of image.

Size of image at the following resolutions Meg a Pixe ls

Ima g e s ize (pi xe ls) 7 2 PPI

We b page 10 0 P PI Ne w s le tt er

17 0 P PI Ne w spa p er

26 6 P PI Ye a rb o ok

30 0 P PI Magazi n e

1 1, 2 8 0 x 960 17” x 13” 12.8” x 9.6” 7.5” x 5.6” 4.8” x 3.6” 4.3” x 3.2”

2 1,600 x 1,200 22.2” x 16.7” 16” x 12” 9.4” x 7.1” 6” x 4.5” 5.3” x 4 ”

3 2,048 x 1,536 28.4” x 21.3” 20.5” x 15.4” 12” x 9” 7.7” x 5.8” 6.8” x 5.1”

5 2,592 x 1,944 36” x 27” 25.9” x 19.4” 15.2” x 11.4” 9.7” x 7.3” 8.6” x 6.5”

8 3,264 x 2,448 45.3” x 34” 32.6” x 24.5” 19.2” x 14.4” 12.3” x 9.2” 10.9” x 8.2”

Page 13: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

Preparing image ResolutionChange image resolution and size in a

paint application like PhotoShop • With the image open in PhotoShop, select from the menu,

Image followed by Image Size. This will display the Image size dialogue box.

Most paint programs will automatically open a new image at 72ppi

This is a very big file.

Page 14: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• Resizing vs. Resampling Resizing an image involves changing the print dimensions without changing the total pixel dimensions. As the resolution is increased, the print size becomes smaller, and vice versa. Resampling, however, involves changing the pixel dimensions and will always introduce a loss in quality.

1st Change Resolution

To change the resolution to 300,

make sure the Resample Image

is deselected. This will automatically

change the document size

also.

Preparing image Resolution & size

Page 15: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• Resizing vs. Resampling Resizing an image involves changing the print dimensions without changing the total pixel dimensions. As the resolution is increased, the print size becomes smaller, and vice versa. Resampling, however, involves changing the pixel dimensions and will always introduce a loss in quality.

Preparing image Resolution & size

2nd Change to desired

document size

To change the document size,

select Resample Image and change

the width to desired document size

Page 16: Digital Image Resolution Image Resolution Preparing Digital Images For press or monitor presentation

Digital Image Resolution

• Files to be printed save as Tif files There is little information lost in Tiff files and printers like to work with them.

• Files to be place on the web save as Jpg files

Jpg files are compressed for small file size and faster down loading. Information is lost in the file through compression, so image quality does suffer a little

Saving files