Home > Articles

  • Print
  • + Share This
This chapter is from the book

Adjusting Resolution

Resolution is an important concept to understand and can be just a little bit complicated because it means different things in different situations. Resolution is what determines the quality of what you see on the screen and what you see in print. You already know that your Elements images are bitmaps. A bit, in this case, is a pixel, an individual picture element. You can enlarge a piece of your image enough to take a good look at individual pixels. Figure 3.5 shows an image of flowers in various stages of enlargement up to 1600%. At that size, you can see that the image consists of little squares in different colors or shades of gray.

Figure 3.5 A pixel is a pixel, how-ever large or small it is.

When you shrink the squares down to a smaller size, let's say 1/72 of an inch, they are too small to be seen individually. What you do see at that resolution is the picture as it appears on your monitor. Typical monitor resolution is either 72 or 96 dpi (dots per inch). (72 dpi is the traditional resolution of older Mac screens. New monitors are more likely to use 96 dpi resolution for a clearer picture. However, most people still think in terms of 72 dpi screen resolution. So will we.) In the case of 72 dpi, a square inch of picture has 72 pixels, squared, or a total of 5,184 pixels per square inch.

When you go to print a picture, you'll see that your printer most likely has a much higher resolution than your screen. So an image displayed in a 1:1 ratio on your monitor will appear smaller when printed because the dots of ink per square inch are more numerous and therefore smaller than screen pixels. Also, an image saved with a low resolution setting will not suddenly become more clear when printed with a high-resolution printer.

Of course, if you have a higher resolution image, you have a lot more data and a much sharper, clearer picture to work with. That also means a bigger file to store and work on. Your hard drive fills up faster. With a larger file, any operation you attempt in Elements will take longer. If you're applying a filter, for example, you're telling the computer to make a specific set of adjustments to each pixel. If the resolution is set to 72 dpi, the computer has to change a little more than five thousand numbers per square inch of image. If it's at 300 dpi, it has to make the same changes an additional 85,000 times per square inch. That adds up.

So, the problem lies in deciding whether you want to work slowly on a large file with high resolution that will print well, or quickly on a smaller file that will look fine on the Web. If you already have plans for the picture, your choice is simple. If it's only going to be seen on the screen, you might as well work at 72 dpi. If you are placing the photo into another document at something close to or smaller than snapshot size, or printing small copies at home on your inkjet printer, you can get away with using 150 dpi as a working resolution. For more flexibility or larger prints, keep the resolution at 300 while you are cleaning it up, cropping, retouching, and so on. You can always save a low-res (lower resolution) copy later. For instance, if you're saving a copy of the picture for a Web page, you can reduce the resolution when you convert it to a JPEG, and end up with a clear and very small file.

Most printers do a fine job of adjusting resolution, particularly if the printer's resolution is a close or exact multiple of the file it's printing. Typically, a home/office inkjet printer will have a resolution of 300, 600, or even as much as 1,200 dpi. If you send a picture that's an exact multiple (for instance, 200, 300, or even 150 dpi), the printed result should have nice even tones with smooth transitions from one color to another. You shouldn't see jagged edges or obvious blocks.

There are times when you have to change the image resolution, even though it may mean losing some image quality. If you have access to a high-end digital camera or scanner, it will present you with very large files at a very high resolution. You may find that you have to reduce the resolution of the image before you can work on it, especially if your computer is an older, slower one or doesn't have enough RAM to work on a large file.

Photoshop Elements does a pretty good job of changing resolution by resampling the image. When you downsample (decrease the number of pixels in an image and thus decrease the image's size), you can reduce the size of the image, or the resolution, or both. Suppose you have a picture that's six inches square. You want it to be three inches square. You open the Image Size dialog box by choosing Image, Resize, Image Size, shown in Figure 3.6, and change the numbers to make the image size 3''x3'' instead of 6''x6''. You don't change the resolution. When you click OK, the image shrinks to half the size it was on the screen. Because you haven't changed the resolution, the file size shrinks to a quarter of what it was.

Figure 3.6 You can change the size and/or the resolution in this dialog box.

If you change the resolution while keeping the image the same size, the screen display will double, because you are now looking at an "inch" that's twice as long (144 pixels instead of 72) .

Downsampling condenses the file information into a smaller spread of pixels, so you won't lose detail in the image as you might when upsampling. When you increase the resolution, Elements has to invent new values for the pixels you're adding. There are three different ways it can do this, and you can choose which of the three to apply by selecting it from the Resample Image pop-up menu at the bottom of the dialog box. Your choices are

  • Nearest Neighbor—This is the quickest method, because it essentially copies what's there, assigning a value to the next pixel based on the average of the ones on either side of it. It works best on edges that are not antialiased. (Antialiasing is a technique that's applied to artificially produced edges such as the curve of a letter or a drawn line. It adds bits of gray along the edge to smooth it out and make it less jagged in appearance.) It will also produce a smaller file. It may, however, result in lines that appear jagged because of the lack of antialiasing.

  • Bilinear —This method, considered better than the nearest neighbor method, is based on averaging the four pixels above, below, and to the sides of a target pixel and assigning it the resulting value.

  • Bicubic —Instead of taking an average of four pixels, the bicubic method takes an average of eight, surrounding the target pixel on all sides and corners. This method produces the best results but takes a longer time to complete.

Figure 3.7 shows the differences between these three methods.

Figure 3.7 This is approximately, but not mathematically, the way it happens.

Remember, too, that the program goes through the entire set of calculations for each pixel in the image. When one is changed, all the ones around it must also change slightly.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020