To do its job of sharpening an image, the Unsharp Mask filter increases the contrast between adjacent pixels. You will need to choose three variables in the dialog: Amount, Radius, and Threshold. B A high Amount percentage for the Unsharp Mask filter produced halos along the edges of the watches A With a high Threshold value of 12 chosen in the Unsharp Mask dialog, the filter sharpened only high-contrast edges but left the watchbands and background still blurry.
B The values shown above note especially the lower Threshold value produced this final, and properly sharpened, version of the image. Amount —, Radius 1—2, Threshold 4—6, or to the point where skin areas start to look smoother. Buildings , objects , etc.
I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time. Pearson Education, Inc. 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.
To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:. 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. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.
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.
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.
To do that, go up to the Edit menu at the top of the screen and choose Fill :. This opens Photoshop's Fill dialog box. Click OK when you're done to close out of the dialog box. Photoshop fills the new layer with gray, temporarily hiding the photo below it from view in the document window:.
Go up to the Blend Mode option in the top left of the Layers panel and change the blend mode for Layer 1 from Normal to Difference :. The Difference blend mode isn't one that's used too often since it tends to make images look, well, different some may even say frightening , as we see with my image after changing the blend mode to Difference:. Believe it or not though, there is a method to the madness. The way the Difference blend mode works is that it compares the layer with the layer s below it and looks for differences between them hence the name.
In other words, with the Difference blend mode, any areas between the layers which are identical become the darkest parts of the image, and we can now use that to locate any areas that are supposed to be neutral gray!
So now, finding a midtone gray area is as easy as finding the darkest part of the image! In Photoshop CS4 or earlier, the Threshold dialog box will appear. Click on the little white triangle at the bottom and drag it all the way to the left:. Similarly, if you move the white point slider to the left at level , Photoshop maps all pixels at level and higher to level The mapping affects the darkest and lightest pixels in each channel.
The corresponding pixels in the other channels are adjusted proportionately to avoid altering the color balance. Moving the middle Input slider to the left makes the overall image lighter. This slider adjustment maps a lower darker level up to the midpoint level between the Output sliders. If the Output sliders are in their default position 0 and , the midpoint is level In this example, the shadows expand to fill the tonal range from 0 to , and the highlights are compressed.
Moving the middle Input slider to the right has the opposite effect, making the image darker. In the Adjustments panel, click the Levels icon or choose Levels from the panel menu. In general, assign equal color component values to achieve a neutral gray. For example, assign equal red, green, and blue values to produce a neutral gray in an RGB image.
Then drag the Shadow and Highlight input sliders inward until they touch the ends of the histogram. Legal Notices Online Privacy Policy. Buy now. Levels adjustment Search. You are commenting using your Facebook account.
Notify me of new comments via email. Notify me of new posts via email. Enter your email address to subscribe to this blog and receive notifications of new posts by email. Email Address:. Sign me up! Brent Paull's Photography Blog. Skip to content. What Do I See? Here is the original image with its original raw file color temperature: Yellow Warbler in an image with a yellow caste to it.
Threshold Icon. Threshold and Layer View. Corrected Color. Share this: Twitter Facebook. Like this: Like Loading
0コメント