How to Change Resolution – All About Images – Research Guides at University of Michigan Library

How to Change Image Resolution Using Adobe Photoshop

Image editing programs like Adobe Photoshop can give you resolution information and allow you to change the resolution of an persona. One would change the resolution of an persona particularly for print purposes, because the quality of the print is dependent on the resolution of the visualize.

1. With Photoshop open, go to File > Open and select your image.
tip : You may right-click and save the tiger image below to use it as a practice image.

2. Go to Image > Image Size

3. An Image Size dialog box will appear like the one pictured below.

( image subtitle : image Size dialogue box. )

4. To change only the resolution, uncheck the Resample Image box.
This lets Photoshop know that we do not want to add or subtract any pixels to the photograph. Adding and subtracting pixels is what happens when we resize images ( to enlarge or shrink them ). To change resolving power we are not changing the number of pixels in the photograph, but changing only how many of those pixels will be displayed per column inch. This will become well-defined as we continue to alter our trope ‘s resolution .

5. In the Resolution field, type in your desired resolution.
You will notice that when you type a value into the Resolution field, the values of the document ‘s width and acme besides change .

6. Click OK to accept the changes.
Congratulations ! You have successfully changed the settlement of an picture !
In this model, we had an persona with a 300ppi resolution. I wanted to print this trope in a professional publication and the visualize needed to be at least 600ppi. The Pixel Dimensions have stayed the same because we did not add or subtract any pixels to the image. however, note that the Document Width and Height decreased by half when the Resolution doubled. Our image started at 10 ” ten 6.667 ” at 300ppi and became 5 ” adam 3.333 ” at 600ppi. This means that in order to print at 600ppi and retain full-quality, I can print this image only arsenic large as 5 ” adam 3.33 ” .

What happens if we decrease our solution from 300ppi to 150ppi ?

As you may have guessed, our Document Width and Height doubled when we halved our resolution. We started with a 10 ” ten 6.667 ” at 300ppi and went to a 20 ” ten 13.333 ” at 150ppi image. nowadays my prototype will print larger, but the quality will be much lower .

What does it all mean?
It ‘s a game of grant and take !
We notice that the pixel dimensions never change. We started with an image at 3000 ten 2000 pixels ( post exchange ) and ended with the dimensions still being 3000 x 2000px. This is authoritative to remember, because when we change solution we are changing only how many pixels will be displayed per inch of the image, not how many pixels make up the image .
Imagine you and a friend each having a bucket full of 5000 seeds to implant in a field. You must use all 5000 of your seeds by planting them in 1 edge squares in a field. nowadays imagine that you are allowed to establish only 150 of your seeds per column inch and your friend is allowed to establish 300 seeds per edge. Both of you have the same number of seeds, but it will take you twice a much coat area in the playing field to plant all of your seeds .
hera ‘s the mathematics to make it more unclutter :
Sample Image is 3000 x 2000 px
600ppi: 3000 pixels / 600 pixels per column inch = 5 inches
2000 pixels / 600 pixels per inch = 3.33 inches
300ppi: 3000 pixels / 300 pixels per inch = 10 inches
2000 pixels / 300 pixels per edge = 6.667 inches

150ppi: 3000 pixels / 150 pixels per inch = 20 inches
2000 pixels / 150 pixels per column inch = 13.33 inches

72ppi: 3000 pixels / 72 pixels per column inch = 41.67 inches
2000 pixels / 72 pixels per column inch = 27.78 inches

How does resolution affect printing?

In this example, our persona has been sent to print from a laser printer on standard 8.5 ten 11 sheets of newspaper .

72ppi:  The document size is sol big that it can not fit onto an 8.5 x 11 tabloid and is clipped. The print choice is highly low, leaving the persona looking very bleary or “ soft ” .
150ppi: The document size is distillery besides big for the 8.5 x 11 tabloid and the quality is mediocre and makes the visualize count satisfactory, but is n’t identical desirable .
300ppi: The prototype about fills up the entire sheet of newspaper and the print quality is very effective with crisp, sharp details.

600ppi: The image is substantially smaller than the early files, but the choice is highly high .
Which one to choose ? The 72ppi and 150ppi images are excessively broken of quality to produce a high-quality print, so they ‘re out. The 300ppi and 600ppi images both looked identical crisp, but the 600ppi image was way besides small. For this example, the 300ppi image would work good because of it ‘s larger photographic print size and high quality .
The key to print images is to find the best resolving power that will produce both the size and quality you need .

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