Generally, an image with a higher resolution produces a better printed image quality. Unless an image is resampled see Resampling , the amount of image data remains constant as you change either the print dimensions or resolution. For example, if you change the resolution of a file, its width and height change accordingly to maintain the same amount of image data. Then change width, height, or resolution. As you change one value, the other two values change accordingly.
With the Resample Image option selected, you can change the resolution, width, and height of the image to suit your printing or onscreen needs. Original dimensions and resolution B. Decreasing the resolution without changing pixel dimensions no resampling C. Decreasing the resolution at same document size decreases pixel dimensions resampling. The file size of an image is the digital size of the image file, measured in kilobytes K , megabytes MB , or gigabytes GB.
File size is proportional to the pixel dimensions of the image. Images with more pixels may produce more detail at a given printed size, but they require more disk space to store and may be slower to edit and print.
Image resolution thus becomes a compromise between image quality capturing all the data you need and file size. Another factor that affects file size is file format. Similarly, color bit-depth and the number of layers and channels in an image affect file size. Photoshop supports a maximum pixel dimension of , by , pixels per image. This restriction places limits on the print size and resolution available to an image.
Printer resolution is measured in ink dots per inch, also known as dpi. Most inkjet printers have a resolution of approximately to dpi. Technically, inkjet printers produce a microscopic spray of ink, not actual dots like imagesetters or laser printers. Printer resolution is different from, but related to image resolution. To print a high quality photo on an inkjet printer, an image resolution of at least ppi should provide good results.
Screen frequency is the number of printer dots or halftone cells per inch used to print grayscale images or color separations. Also known as screen ruling or line screen , screen frequency is measured in lines per inch lpi —or lines of cells per inch in a halftone screen. The higher the resolution of the output device, the finer higher a screen ruling you can use. The relationship between image resolution and screen frequency determines the quality of detail in the printed image.
To produce a halftone image of the highest quality, you generally use an image resolution that is from 1. But with some images and output devices, a lower resolution can produce good results. If you are printing an image on a nonhalftone printer, consult your service provider or your printer documentation for the recommended image resolutions.
If you plan to print your image using a halftone screen, the range of suitable image resolutions depends on the screen frequency of your output device. Photoshop can determine a recommended image resolution based on the screen frequency of your output device. If your image resolution is more than 2. This means that the image resolution is higher than necessary for the printer.
Save a copy of the file, and then reduce the resolution. Produces a resolution that is the same as the screen frequency no lower than 72 pixels per inch. The image is redisplayed in its approximate printed size, as specified in the Document Size area of the Image Size dialog box. Resampling is changing the amount of image data as you change either the pixel dimensions or the resolution of an image.
When you downsample decrease the number of pixels , information is deleted from the image. When you resample up increase the number of pixels, or upsample , new pixels are added. You specify an interpolation method to determine how pixels are added or deleted.
Downsampled B. Improve this answer. Linh Ta Linh Ta 5 5 silver badges 9 9 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta. Now live: A fully responsive profile. Tip: You may right-click and save the tiger image below to use it as a practice image. Image Caption: Image Size dialog box. This lets Photoshop know that we do not want to add or subtract any pixels to the photo. Adding and subtracting pixels is what happens when we resize images to enlarge or shrink them.
To change resolution we are NOT changing the number of pixels in the photo, but changing only how many of those pixels will be displayed per inch.
This will become clearer as we continue to alter our image's resolution. You will notice that when you type a value into the Resolution field, the values of the document's width and height also change.
You have successfully changed the resolution of an image! In this example, we had an image with a ppi resolution. I wanted to print this image in a professional publication and the image needed to be at least ppi. 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 Resolutio n doubled. Our image started at 10" x 6.
This means that in order to print at ppi and retain full-quality, I can print this image only as large as 5" x 3. What happens if we decrease our resolution from ppi to ppi? As you may have guessed, our Document Width and Height doubled when we halved our Resolution.
We started with a 10" x 6. Now my image will print larger, but the quality will be much lower. We notice that the pixel dimensions never change.
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