CorelDRAW X5 The Official Guide part 73 pdf

10 271 0
CorelDRAW X5 The Official Guide part 73 pdf

Đang tải... (xem toàn văn)

Thông tin tài liệu

● Add The Add(itive) mode applies transparency in a similar fashion to Normal mode, except it whitens and brightens the result—seriously! In English, there’s a subtle but distinct different between “plus” and “added to”; similarly, Additive mode moves the combined result of the target and source object colors in a positive direction in brightness value. The artistic result is good for adding subtle shading to composition areas; this is something painters through the centuries could not do without the added step of applying pure white, because inks and pigments use the real-world subtractive color model. ● Subtract This mode ignores the brightness value in the source object and is similar to mixing physical pigments. If you use Subtractive transparency mode on green and red objects and overlap then with a target blue object, the result color will be black. ● Difference Remember color opposites on the color wheel? This is what Difference mode performs; it moves the result color to the difference (on the color wheel) between the source and target colors. For example, a red Difference transparency object over a yellow target object produces green areas. You’ll see the difference effect most clearly if you put such an object over an empty area of the drawing page. A red difference object will cast cyan as the result on the page. This is a useful blending mode for creating dramatic lighting effects—for example, you can shine a Difference mode drawing of a shaft of theater spotlight on an object, and get truly wonderful and bizarre lighting effects. ● Multiply Multiply always produces a darker result color from merging the source and target objects. Its effect is similar to wood stain or repeated strokes of a felt marker on paper. Several objects in Multiply mode, when overlapped, can produce black, and this is perhaps the best mode for artists to re-create real-world shadows cast on objects. ● Divide The Divide mode produces only a lighter result color if neither the target nor source object is black or white. Use this mode to bleach and produce highlights in a composition by using a light color for the transparency object such as 10% black. ● If Lighter The source (top transparency) object lightens the underlying object color only if the source color/tone is lighter. If the source is darker, there is no visible effect. ● If Darker Similar in effect to Multiply mode, If Darker calculates a new result color if areas in the target object are lighter. If the underlying target object is darker, there’s no or very little change. It’s particularly interesting to view the result when an If Lighter or an If Darker object is placed above a fountain-filled target object. You will see clipping, a hard edge where the fountain fill reaches a specific value where the result color doesn’t qualify to display a change. 684 CorelDRAW X5 The Official Guide ● Texturize This mode will not produce much of a change unless you fill the source object with a bitmap or pattern fill. However, if, for example, you fill the transparency object with a bitmap fill, the result is a shaded and patterned area. This mode removes the hue and saturation from the bitmap fill, leaving only brightness values—in effect, making your target object a shaded version of the original, sort of like merging a grayscale photograph over an object. This is a useful mode when you do not want the target object to influence the result colors with any distinct hues, and you can use this mode to quickly build up texture and simulate real-world complexity in your composition. ● Hue The Hue merge mode changes the result color to the hue of the target color, without affecting saturation or brightness in the result. This mode is useful for tinting compositions, and the target object colors are ignored in the result. ● Saturation The Saturation merge mode can be used to remove color from the result; it’s quite nice at making black-and-white photographs from color images. The best use of Saturation transparency mode is with shades of black as the transparency object’s fill, over a color object such as a bitmap photo. You need to make Transparency zero (0) in order to remove all color from an object, photograph, or vector object. The lighter the shade of black, the less saturation in the target object is removed, and as you increase the amount of transparency, the target object becomes tinted instead of containing a rich color. Highly saturated target and source objects will produce no change in the result. ● Lightness This is a great mode for brightening the result colors of the bottom object or bitmap because the target object’s colors are never changed, just the lightness (also called “value” or “brightness”). Try using a bright yellow transparency object at 0 percent Transparency—blacks in the bottom object or photo will be completely removed. Transparency objects that are not bright—such as a deep blue—will only make the resulting object look muddy, so stick to low transparency amounts and bright colors for the transparency object on top. ● Invert This merge mode produces the most predictable—and visually interesting— results, if your transparency object is a photo or bitmap painting with lots of different hues and the target object is a shade of black. Invert merge mode produces a result whose original colors become the color complement as a result—colors directly opposite their originals on a traditional color wheel. The less opacity you use with the target photo, the more pronounced the colors become. You can simulate a photo negative using Invert mode. If you use a solid color object such as an ellipse over a color object, the target object will still become its color complement, but the areas it lies over will merely blend the inverted target object color with the original color of the bottom object. CHAPTER 22: Lens Effects, Transparency, Shadows, Glows, and Bevels 685 22 ● AND, OR, and XOR The AND function includes similarity between the source and target objects; for example, two red ellipses that overlap and that both have the AND transparency merge mode appear not to be transparent at all, but instead display 100% red where they overlap. This is a useful mode when you want only a color result in overlapping areas, because AND creates no change outside of the overlapping result area. The OR operator is an exclusive operator; it excludes stuff: this is a good mode for clipping a color change, thus limiting it only to areas where the target and source objects overlap. You’ll see nothing outside the overlapping areas when the target object has the OR operator. XOR is a Boolean math statement, based on something called a truth table, where certain conditions must be met to produce a result. However, you might not find a need for this transparency mode unless you use more than two objects in a design area; if either or neither object in an XOR operation is similar, you’ll get no result color. This operation works only if there is one differently colored object in the color calculation operation. Boolean math, invented by George Boole (1815–1864), adds human-understandable language to math operations. You use it all the time when you use CorelDRAW’s Shaping docker. When you perform a Trim operation, for example, mathematically (geometrically) the command is expressed as “choose A, but not where B overlaps A.” ● Red, Green, and Blue Each of these merge modes filters out a respective (RGB) channel, and the native color of the source object is ignored. This is a useful transparency mode for color correcting photographs you import to CorelDRAW; for example, if you put a Green transparency mode object over a portrait, and then play with the amount of transparency on the property bar, you can sometimes correct for harsh indoor (particularly cheap fluorescent) lighting. Creating Multi-Stage Transparencies You might find you need a transparency object that’s more complex than the fountain types offered on the property bar; for example, a lens flare can add a lot of photorealism to an illustration, and this type doesn’t appear to be on the property bar. CorelDRAW’s Transparency tool’s power can be extended by building a multi-stage fountain fill for an object, and then using the Transparency tool in a blend operation that hides certain colors in the fountain fill. Take a look at the lens flare in Saturn.cdr. To create the effect, you drag shades of black from the Color Palette, and drop them onto the marker connector, as shown next. Remember, darker shades represent transparency, and lighter shades stand for opacity. You might want to reposition the new markers once you’ve added them; this is done by click-dragging with the Transparency tool. If your drop point for a new marker isn’t exactly over the marker 686 CorelDRAW X5 The Official Guide connector (the blue dashed line), your cursor will turn into an international “no can do” symbol. Ill 22-7 Pattern and Texture Transparencies Pattern and Texture transparencies can add texture to object fill areas below the object, creating intricate detail. The Transparency Type drop-down menu includes Two Color Pattern, Full Color Pattern, and Bitmap Pattern transparency types. With any of these selected for the transparency type, the Starting Transparency slider controls the percentage of transparency applied to brightness values in the chosen bitmap that lie above 126 on a brightness scale of 0–255 (256 shades); the Ending Transparency slider controls the percentage of transparency applied to brightness values in the chosen bitmap that fall below 128. Figure 22-10 shows Shirt.cdr, a file you should feel free to experiment with, along with the options on the property bar when the Transparency tool is chosen and with the control handles above the target object; you work with scale, rotate, and skew in addition to setting the center point for the transparency exactly as you would rotate and scale an object in CorelDRAW. CHAPTER 22: Lens Effects, Transparency, Shadows, Glows, and Bevels 687 22 Radial Transparency Drag color well shades onto marker connector. Clearly, CorelDRAW not only provides you with a robust feature set, but it also provides you with enough Hawaiian shirt patterns to last you for several months of vacationing. Using Transparency Freeze Freezing a transparency object captures the composite of the object’s properties combined with whatever was beneath the object before using the Freeze button on the property bar. 688 CorelDRAW X5 The Official Guide FIGURE 22-10 Add both color and a texture to underlying bitmaps and drawings with the Texture Transparency types. Pattern, bitmap, and texture fills Transparency Operation (merge modes) Libraries Transparency Type Starting Transparency Slider Ending Transparency Slider Freeze Transparency Mirror Transparency Tiles Origin Scale/Rotate Skew Edit Transparency Deactivating the Freeze option (without ungrouping it) returns a transparent object to its current and active state. This means if you freeze the object, move it, and then unfreeze it, its interior will display whatever is currently under it. Using the Bevel Effect The Effects | Bevel docker provides you with a means to make objects dimensional, but not as completely 3D as the Extrude tool performs. The Bevel docker offers two different types of engraving effect: emboss and soft edge. The emboss effect is an automated routine that creates duplicates of an object, offsets them, and gives them different colors to create the effect of, for example, a seal crimped onto a piece of paper like notary publics do. Although you can manually create this emboss effect, the Bevel docker creates a dynamic, linked group whose color and position can change when you define different light intensities and light angles. Here are visual examples of the emboss effect. If you choose to use emboss, it’s a good idea to create a background for the object, because either the highlight or the shadow object might not be visible against the page background. Usually, a color similar to the background will serve you well for the object color. You can use any fill, including bitmaps and fountain fills, for the object you want to emboss, but the resulting emboss objects will feature not the fill, but only solid (uniform) colors. Ill 22-8 CHAPTER 22: Lens Effects, Transparency, Shadows, Glows, and Bevels 689 22 Original Two offset duplicates create the effect. Here you can see the Bevel docker and the options you have while applying the emboss effect. Ill 22-9 Here’s a rundown of what the options do on the Bevel docker in Emboss mode: ● Bevel Offset – Distance (The To Center option is only available in Soft Edge mode.) This combination num box and spin box is used to set the distance of the duplicate objects from the original. You don’t gain anything visually by setting a high value for an object; rather, this box is used to set a relational distance, depending on the size of the object to which you apply the emboss effect. For example, a 4" object will look nice and embossed if you use a 0.09" Distance, but the effect looks a little phony at greater distances. On the other hand, an 8" object will probably not look embossed with a 0.09" Distance setting—however, 0.16" scales the effect proportionately to the object, and the emboss looks good. Use distance as a scaling factor. Also, distance does not auto-scale when you scale the control (parent) object. Therefore, if you need to resize an object, plan to redefine the distance for the emboss effect after you scale the parent object. 690 CorelDRAW X5 The Official Guide Style (Emboss or Soft Edge) Highlight color Shadow color Controls contrast of effect Controls angle of emboss Distance of objects from control object ● Shadow Color The color of the object has a direct influence on the color of the shadow object behind the control object. For example, if you create an emboss effect with a blue object, the shadow object will be a dark blue, even if you set the color to black. You can neutralize the shadow color by defining the color opposite of the control object; for example, if you have a cyan circle, set the Shadow Color to red, the color complement of cyan. Regardless of what color you choose for the shadow object, the result color will always be duller than the color you define, because— well, it’s a shadow! Shadow color is unaffected by the Intensity option. ● Light Color This controls the color of the highlight object; it affects neither the control object’s color, nor the color or brightness of the shadow object. Light color at full intensity displays the color you choose, and as you decrease intensity, the light color blends with the object color—light color does not depend on any object’s color you might have beneath the effect. As light intensity decreases, a bitmap-filled object’s highlight color will move from its original color to white. ● Intensity Use this slider to control the contrast of the emboss effect. Although the shadow object’s color is not affected by intensity, the highlight object’s color is. High values display the highlight object’s color most faithfully, while lower Intensity settings dull the highlight color and move its hue toward the control object. ● Direction Use this slider to control the direction that light seems to cast on the emboss object(s). A Direction setting of 0° points the highlight at 3 o’clock, traveling counterclockwise. Therefore, if you need a highlight on an emboss effect at 11 o’clock (a very classic lighting position), you’d set the Direction at about 160°. ● Altitude This option is reserved for the bevel effect, covered shortly. Creating Soft Edge Bevel Effects The other mode on the Bevel docker, Soft Edge, performs a lot more calculations than the emboss effect and actually creates a bitmap image, masked by the control object, which can be dynamically adjusted. The Shadow Color, Light Color, Intensity, and Direction options on the docker produce predictable results, much like those you get when using Emboss mode, but because the soft edge effect is generated to bitmap format, the results look more detailed, refined, and almost photorealistic in appearance. In addition to having an Altitude slider in this mode, you have To Center as an available option in the Bevel Offset field. Here’s what To Center does and how it works. All soft edge bevels are produced from the edge of an object traveling toward its center. If, for example, you’ve created a circle that’s 3" across and then type a Distance offset value in the num box in any amount smaller than 1.5", you’ll see a dimensional, sloping bevel created inside the circle, with a flat top in the shape of the circle in its center. If, however, you type in a value greater than 1.5", the center of the object will bevel to a point, and the front face of the object is entirely lost. The reason this happens (you might or might not CHAPTER 22: Lens Effects, Transparency, Shadows, Glows, and Bevels 691 22 want this visual effect), is that the bevel effect travels toward the interior of the object, and half of the 3" diameter of this circle is 1.5". Just keep in mind the size of the object to which you apply a bevel to gain total control over the effect. If, on the other hand, you intend for the sides of the bevel to come to a point, you don’t need to set values in the Distance field; you choose To Center, click Apply, and CorelDRAW creates the maximum width bevel, meeting at a point inside the object. You can create interesting marine creatures such as a starfish by using the Polygon tool to create the silhouette of a starfish, fill the object, and then To Center auto-creates a very lifelike composition. Here are two very different looks for the bevel effect: at left a Distance has been set for the offset, and at right To Center is chosen. Ill 22-10 Altitude Altitude determines the angle of the sun illuminating the bevel effect…if the sun were actually involved in created the effect. Altitude is a simulation that does something a little different than Shadow Color and Light Color do to increase and decrease the contrast of the effect. At Altitude settings that approach 90°, you lessen the difference in brightness between the darkest and lightest areas in the bevel effect. Think of a coin on the sidewalk at high noon; you can’t really see the embossed president, queen, or other famous person on the coin because the bulges and recesses on the coin are fairly evenly lit. It’s the same deal with the bevel Altitude setting; smaller Altitude amounts cast the hypothetical sun closer to the hypothetical horizon, and you get a lot more contrast on the bevel. If you want the bevel effect to produce the greatest visual impact with your work, you’ll use a moderate Altitude value most of the time. Using the Drop Shadow Effect With the Drop Shadow tool and the options available on the property bar when this is the active tool, you can create both shadows and glows, based on the shape of the target object (or group of objects). Although this section walks you through several variations, basically 692 CorelDRAW X5 The Official Guide Distance: 0.18" To Center chosen you have three different types of effects at hand when you use the Drop Shadow tool, as shown in Figure 22-11. ● Flat shadows The presets with the prefix “Flat” create the impression that you’re viewing an object from the front and that the object is basically lit from the front. These shadow types, also called drop shadows, are a popular effect; however, they don’t always bring out depth in a composition, because the drop shadow suggests a face-front orientation of a scene—a viewpoint usually reserved for driver’s license photos and wanted posters in the post office. However, drop shadows will indeed perk up a web page, because the audience expects a face-front orientation, since we all tend to face the front of our monitors. ● Perspective shadows This effect is sometimes called a cast shadow. The effect suggests a shadow casting on the ground and diminishing in size as it travels to a scene’s vanishing point. It visually suggests that the audience is looking into a scene from a perspective point and is not looking at an object placed on a scene, as drop shadows tend to do. CHAPTER 22: Lens Effects, Transparency, Shadows, Glows, and Bevels 693 22 FIGURE 22-11 The drop shadow effect can have perspective and can be used to light up a scene, not simply to make things cast shadows. Flat (drop) shadow Perspective (cast) shadow Glow . object captures the composite of the object’s properties combined with whatever was beneath the object before using the Freeze button on the property bar. 688 CorelDRAW X5 The Official Guide FIGURE. reposition the new markers once you’ve added them; this is done by click-dragging with the Transparency tool. If your drop point for a new marker isn’t exactly over the marker 686 CorelDRAW X5 The Official. you need to resize an object, plan to redefine the distance for the emboss effect after you scale the parent object. 690 CorelDRAW X5 The Official Guide Style (Emboss or Soft Edge) Highlight color Shadow

Ngày đăng: 04/07/2014, 06:20

Từ khóa liên quan

Tài liệu cùng người dùng

Tài liệu liên quan