Photoshop cs5 cho nhiếp ảnh gia part 57 docx

351 ■ FILTERS Note: You can create customized brush tips to use when painting by going to Window > Brush and click- ing one of the preset bristle tips as shown here. A Bristle Qualities dialog appears in which you can specify the various parameters of the bristle tip. Experiment with the settings to get precisely the effect that you need. Filters Photoshop includes a huge array of filters that make it easy to distort your picture in all sorts of ways. Some of the filters correct problems in the image such as vignetting or pin cushion/barrel distortion, while others are primarily to add artistic expression. It’s beyond the scope of this book to cover them all, but we’ll describe a few that we find particularly useful. However, the best way to get familiar with the filters is to open an image and begin experimenting. We’ll begin by describing how to use Smart Filters and regular filters. Note: If you opt for the “experimental” approach, it’s a good idea to turn on the History Log in your General Preferences (refer to Chapter 4, “Foundations,” for details) so that you can remember what you did if you stumble across something wonderful! In fact, any time you are being “creative” with your image, it’s smart to turn on the History Log. You may think you’ll remember exactly what you did, but if you’re any- thing like us, at some later date you’ll be frustrated because you can’t recall how to replicate the effect. Since Elements does not provide a history log, we recommend using a notepad to keep track of what you’ve done to your image. Using Smart Filters on Smart Objects CS5 has Smart Filters, meaning that filter effects can be readjusted repeatedly, even if you close and reopen the image. This is a welcome feature, very similar to the flex- ibility of the adjustments in adjustment layers. By using Smart Filters, you can create different combinations of filter effects that you can dynamically adjust as desired. Unfortunately, Smart Filters are available only for certain filter effects with 16-bit 607343c09.indd 351 4/11/10 11:07:35 PM 352 c h a p t e r 9: CREATIVE EFFECTS ■ images but are available for all filters with 8-bit images. (For more explanation of Smart Filters and Smart Objects, refer to Chapter 5, “Workflows and First Steps.”) Note: The following filters can be used as Smart Filters with 16-bit images: all Blur filters except Smart Blur and Lens Blur; Lens Correction; all Noise filters; all Render filters except Lighting Effects; all Sharpen filters; and Emboss, Find Edges, and Solarize from the Stylize group. Some third-party plug- ins, such as Noiseware Pro from Imagenomic (www.imagenomic.com) and Silver Efex Pro, are also compatible with 16-bit images. The ultimate in flexibility is to have a raw image placed as a Smart Object at the beginning of your workflow, with Smart Filters applied to the raw image. Cur- rently there are some limitations that will sometimes cause you to have to make some workflow choices. For example, a cleanup or cloning layer will not update to reflect any further changes you make to the Smart Object raw file. If you do your dust cleanup in ACR, or the cleanup layer contains only a few pixels to cover some very small dust spots and the Smart Filters you want to use are for sharpening, you’ll be fine. But if you readjust the color or tonality of the raw file in any way or use a filter that causes a dramatic effect, the clone layer will be outdated and need to be redone. We recommend that when you want to experiment with creative filter effects you create a duplicate version of your optimized image and then flatten it by choosing Layer > Flatten Image. By doing this, you can save your optimized file as a 16-bit file. Note: An alternative approach is to create a Stamp Visible layer at the top of your workflow by holding down the Alt/Option key and choosing Layer > Merge Visible. Make certain to continue to hold down the Alt/Option key while clicking Merge Visible. This will create a new composite layer at the top of your workflow to use for your creative filter effects. The advantage of this approach is that the entire file is stored together. The downside is that you may have to convert the entire file to an 8-bit image. If you have no use for the file without the creative filter effects, then this approach may be preferable. To use most of the creative filters, you’ll need to convert the image to an 8-bit file, but first convert the image to a Smart Object by choosing Filter > Convert for Smart Filters. This will change the layer into a Smart Object (that will refer to the image as it was originally opened in this file, but not the original raw file), and the fil- ters you apply will be editable. Then convert the image to an 8-bit file if necessary for the particular filters you want to use by going to Image > Mode > 8-Bit. When you want all the filter effects to apply to the same areas of the image, you can use the Smart Filter layer mask and paint the mask white or black to show or reveal the effects, just as you did with adjustment layer masks. If you want one filter to affect part of the image and another filter to affect a different area, it gets a little more complicated. In Figure 9.11 we used a Smart Filter to make a highlight shadow adjustment on part of the image and then created a second Smart Filter to apply a texture to the overall image to make it appear as though it were printed on canvas. To do this, after we applied the Shadows/Highlights adjustment as 607343c09.indd 352 4/11/10 11:07:35 PM 353 ■ FILTERS a Smart Filter, we copied the Smart Object layer by dragging it to the New Layer icon, then we rasterized the new layer and then converted it back to a new Smart Object and applied the texture to the entire image. To apply any Smart Filters to different parts of the image (or just one Smart Filter to the entire image), follow these steps: 1. Begin by applying the Smart Filter to the image and masking out any areas you don’t want to be affected. 2. Duplicate this layer. 3. Go to Layer > Smart Object > Rasterize. This will apply the effects of the filters on the previous layer. 4. Go to Filter > Convert for Smart Filter. This will turn this layer back into a Smart Object that includes the effects of the previous layer. That way, you can apply additional filters and use the layer mask to apply the effects differently than you did in the previous layer. Use the layer mask to reveal only the portion of the image you want to be affected by this filter or to subdue the effects of the filter beyond what’s available in the filter settings. Figure 9.11 Using Smart Filters sometimes involves a series of steps. Ph o t o b y EllEn An o n 607343c09.indd 353 4/11/10 11:07:39 PM 354 c h ap te r 9: CR E AT I V E E F F ECT S ■ Using Filters without Smart Objects Just as with Smart Filters, since most of the creative filters work on 8-bit images only, we recommend that you duplicate your optimized master file and create a separate file to do your creative work. That way, the master file remains a 16-bit file, and the cre- ative file is 8-bit. If you have no use for the original file without the creative effects, you may pre- fer to create a Merge Visible layer at the top of the workflow by holding down the Alt/ Option key and choosing Layer > Merge Visible. Be certain to continue to hold down the Alt/Option key while clicking Merge Visible. Apply the filter effects to this layer. Then you can reduce the effect later by adjusting the opacity of the layer, or you can add a layer mask to apply the filter to specific parts of the layer only. If the filter effect you want to apply is grayed out, it means that you’ll need to convert the file to 8-bit. To do so, select Image > Mode > 8-Bits/Channel. Note: Many filters take considerable time to process. If you are going to experiment with different effects, a useful trick is to duplicate your image by choosing Image > Duplicate and significantly reduce the size of the duplicate file. Then experiment with the filters on the smaller file. When you have estab- lished a combination of filters and settings that you are satisfied with, apply the same combination to your original file. Some filters are processed only using RAM. If a filter requires all your available RAM to process an effect, you may get an error message. Try closing other running programs to free up some RAM. For Photoshop Elements Users: Applying Filters Elements does not have Smart Filters. When you want to have the convenience and power of a layer mask with the filtered version of the image, we recommend following Steps 1–4 from the “For Photoshop Elements Users: Colorizing Black-and-White Images” sidebar earlier in this chap- ter to create a layer with an adjustment mask. Then, once you’ve applied a filter, if you are going to continue to work on the image, create a Stamp Visible layer before moving on. Lens Correction Filter The Lens Correction filter is used to correct distortions that appear in your image due to limitations of various lenses. It has been dramatically improved in CS5 and is worth becoming familiar with so you will immediately know how to proceed if you find chromatic aberration or vignetting in any of your images. In addition it can help correct for distortion due to not holding your camera on a parallel plane with your subject (that’s what often causes buildings to look as though they’re falling over), to straighten the image, or to add a vignetting effect. The Lens Correction filter can be used on 8-bit or 16-bit images, as well as on Smart Objects, and is best applied before you crop or distort the image in any For Photoshop Elements Users: Applying Filters Elements does not have Smart Filters. When you want to have the convenience and power of a layer mask with the filtered version of the image, we recommend following Steps 1–4 from the “For Photoshop Elements Users: Colorizing Black-and-White Images” sidebar earlier in this chap - ter to create a layer with an adjustment mask. Then, once you’ve applied a filter, if you are going to continue to work on the image, create a Stamp Visible layer before moving on. 607343c09.indd 354 4/11/10 11:07:39 PM 355 ■ FILTERS way. Therefore to use it we recommend converting your background layer to a Smart Object (Filter > Convert for Smart Object ) or by creating a Merge Visible layer at the top of your workflow. When you choose the Lens Correction filter, a new window opens as shown in Figure 9.12, featuring a tab that offers automatic corrections of a variety of lens related issues as well as a Custom tab that has settings that are closer to what was present in earlier versions of Photoshop. (The Elements version is very similar to the Custom tab and has fewer options.) Figure 9.12 The Lens Correction lter oers both automatic and manual correction of various types of image distortions caused by lenses. The auto settings last used in the Lens Correction filter are “sticky.” That means that each time the filter opens, it displays the settings that you used the last time. So if you applied an auto adjustment, the auto settings will be applied to the new image as well. You may well need to choose a different profile for the auto settings for the new image, or to turn them off all together by unchecking the Auto Correction tab. The Auto Corrections are new to CS5 and are dependent on profiles for each specific lens and camera combination. To use the Auto features fill in the search crite- ria with the details of your camera make and model, along with the lens. From the fly- out menu, be sure to check Match Sensor Size, but you will usually not check Prefer Raw Profiles. For a given lens profile, there can be both RAW (generated with RAW image files) and non-RAW (generated with non-RAW images, usually JPEGs, but pos- sibly TIFFs) versions of the profile. Since images are already past their RAW stage when they are opened in Photoshop > Filters> Lens Correction, the plug-in defaults to show the available non-RAW profiles for a given camera make/model/lens combina- tion. If a non-RAW profile does not exist for a certain combination but a RAW profile 607343c09.indd 355 4/11/10 11:07:39 PM 356 c h a p t e r 9: CREATIVE EFFECTS ■ does exist, the plug-in will display the RAW profile. If profiles for your lens appear, choose the best one (Adobe is rating the profiles based on the number of parameters taken into consideration while developing the profile) and proceed as needed to fine- tune the lens corrections on the Custom tab. Although Adobe is supplying some profiles, they are unable to create every pos- sible combination of camera body and lens. The hope is that camera lens manufactur- ers, and others, cooperate and also offer profiles. Therefore they’ve created free Lens Correction Profiler software so users can develop their own custom profiles, available from the Adobe website. To access it, open the fly-out menu in the Lens Profile section of the interface, and choose “Browse Adobe Lens Profile Creator Online.” Creating custom profiles takes some time, so Adobe has also made it possible for people to upload profiles to a website. The easiest way to access the additional profiles is to click the “Search Online” button in the Lens Correction interface. To use online profiles, take these steps: 1. Open an image into Lens Correction. The image must contain camera make, camera-body model, and lens model metadata to gain use of the online profile search feature. 2. Click the Search Online button, located in the Auto Correction tab. 3. If online profiles are found, the Lens Profiles menu will populate with online profiles. These feature a globe icon next to their names. 4. Click on a given online profile to preview the Auto Correction on the image (make sure your Auto Correction check boxes are checked). You can even OK the dialog and apply these corrections without having to save the online profile to your computer. 5. If you like the online profile, use the Lens Profiles flyout menu and click Save Online Profile Locally. This will save the online profile onto your computer so you can use it anytime. From the same fly-out menu, you can select a profile and choose Show in Finder (or Show in Explorer on a PC) to see the location of the profile, and delete it if you decide you no longer want it. You can also choose the Browse Adobe Lens Profile Creator Online command. With the correct profile selected, check the boxes to correct Geometric Distor- tion, Chromatic Aberration, or Vignetting as needed. If you check Auto Scale Image, Photoshop will fill the space with the image after the image is stretched or pulled to remove the distortions. We prefer to initially leave Auto Scale Image unchecked and have the Edge drop-down set to Transparency. That way we can see how much of the image will be modified near the edges. We often then check Auto Scale Image and visually inspect the results, particularly near the edges. Choosing Edge Extension from the Edge drop-down menu will cause Photoshop to automatically fill in the transpar- ent edges, but in our experience this is often not done well if there is significant area to be filled. If the area is very limited, then it may work reasonably. To manually correct barrel or pincushion distortion, click on the Custom tab and then click the Remove Distortion icon on the top left of the interface. Then 607343c09.indd 356 4/11/10 11:07:40 PM 357 ■ FILTERS place the cursor over the image and drag left or right. The icon beneath the barrel is the Straighten tool and works the same way as it does in ACR. Next is the Move Grid tool . This allows you to place the grid in the most helpful position to accu- rately reduce the various distortions. The Hand tool and Zoom tool icons work as they do elsewhere in Photoshop. Use the Custom tab shown in Figure 9.13 to manually apply any corrections you choose, or to tweak the auto corrections. Note that in the Chromatic Aberration area you have the option to control green/magenta fringing in addition to the red/ cyan and blue/yellow fringing sliders that are available within ACR. Whenever you are removing chromatic aberration, it’s a good idea to zoom in to at least 100% mag- nification. Then adjust the sliders one at a time to remove the color halos as shown in Figure 9.13. Figure 9.13 Zoom in to at least 100% magnication as you adjust the sliders to remove chromatic aberration. You can apply or remove vignetting as you wish by using the vignette controls. In some cases you may opt to leave some vignetting to subtly draw the viewer’s eye into the image, while in other cases you may want to add vignetting for that purpose. Note that when creating a vignette you can create a dark vignette or a light one. Both ways can be effective. It’s up to your creative vision to decide which you prefer. Similarly, using the Custom tab, you can transform the vertical and/or horizon- tal perspectives to correct for distortions caused by not having your lens parallel to the plane of focus of your subject. Although perspective distortion is most often evident in buildings that appear to be leaning forward or backward, it can be an issue for nature photographers in some situations and results in slight distortion of your subject matter. Rather than setting the angle directly, we find it easier to use the Straighten tool , located on the upper left of the Lens Correction interface, to draw a line 607343c09.indd 357 4/11/10 11:07:40 PM 358 c h a p t e r 9: CREATIVE EFFECTS ■ along a surface that should be horizontal or vertical and let Photoshop automatically determine the angle. At times scaling is helpful to retain some parts of your image that become hid- den due to the distortion correction that’s applied. Scaling gives you the option to include extra canvas around the image or to move in on the image, thereby eliminat- ing the blank canvas. On the Auto Correction tab you can opt to leave extra canvas transparent or have Photoshop try to fill it in by choosing Edge Extension. That way the additional canvas may come close to matching surrounding areas of the image. However, most of the time you’ll still need to do some additional cloning and healing to make certain the new canvas blends seamlessly with the rest of the image. Although many of the Lens Correction controls are also available within ACR, some offer more options within the PS interface, as well as the ability to use a mask in conjunction with the filter. For Photoshop Elements Users: Removing Distortion in Elements Elements has a similar filter for eliminating distortion, which you access by going to Filter > Correct Camera Distortion. The interface, as seen here, is very similar to the custom tab in the CS5 version of the filter; however there are fewer controls and no automatic controls. We do not advise using the Angle control here to straighten an image, because it’s difficult to accurately set the correction angle. Rather, we prefer to use the methods we discussed in Chapter 5. 607343c09.indd 358 4/11/10 11:07:41 PM 359 ■ FILTERS Blurs Photoshop CS5 has an impressively long list of blurs, but we’ll cover only the ones that are particularly applicable to nature photographs. We find that Gaussian blurs, and occasionally lens blurs, are the main ones we use. You may want to explore other blurs, such as smart blurs, motion blurs, and zoom blurs as well. Gaussian Blurs Gaussian blurs produce a hazy effect and blur the image by an adjustable amount. They’re quite useful when you want to blur a section of your image. However, it’s important to remember that if you make a selection of the area you want to blur, a Gaussian blur considers that selection a general guideline, but not an absolute man- date, for the boundaries of the blur. This transition area between blurred and not blurred sections is more apparent the more blur you apply. At times it can create a glow around your subject, as it does in the photo in Figure 9.14. Figure 9.14 Although the background was selected when the Gaussian blur was applied, it included some of the pink from the spoonbill, resulting in a pleasant glow around the bird. Ph o t o b y EllEn An o n To apply a Gaussian blur, take the following steps: 1. Make a copy of your Background layer and convert the layer for a Smart Filter by choosing Filter > Convert for Smart Filter. 2. You may choose to first select the area to apply the blur to using any of the selection tools, or you may prefer to rely completely on painting a layer mask. 607343c09.indd 359 4/11/10 11:07:42 PM . Auto Scale Image and visually inspect the results, particularly near the edges. Choosing Edge Extension from the Edge drop-down menu will cause Photoshop to automatically fill in the transpar- ent. 5. 607343c09.indd 358 4/11/10 11:07:41 PM 359 ■ FILTERS Blurs Photoshop CS5 has an impressively long list of blurs, but we’ll cover only the ones that are particularly applicable to nature photographs. We. select a profile and choose Show in Finder (or Show in Explorer on a PC) to see the location of the profile, and delete it if you decide you no longer want it. You can also choose the Browse Adobe