PHOTHOSHOP's mask technology

Everyone who paints a room or house knows that covering the strip is an essential tool to determine what to paint and what not to paint. We stuck a strip of glue on a window pane, painted the window frame, and then tore the strip off. The glass was not painted. Adobe Photoshop also has a roll of overlays - digital strips - that are hidden in three different places: constituencies, alpha channels, and masks. Digital tape is better than the actual cover tape - you only need to learn how to effectively manage it and use it skillfully. Someone can write a book on hundreds of techniques for making constituencies. These selection areas specify where the mask is placed. But it comes down to one thing: There is a good transition between constituencies and unselected areas. Borrow the phrase from Ultimatte's people: "There is no margin... only transition." A non-smooth transition will lead to an edge overflow. The background color spills over to the mask portion of the image. When the image is placed on a different background, the image looks unnatural and is not positioned properly. (See "Shrink and Expand Edges"). In this article, I discussed some tips. They can help readers quickly obtain high-quality constituencies and combine the selection with images. These techniques are equally applicable to other uses, such as making a selection before performing a filter or using a drawing tool. In some cases, market plug-ins (mentioned below) can complete this operation faster and better. But with a little practice, you should be able to make constituencies easier and more proficient. The principle of the mask If you can only get one thing through this article, then it should be like this: In Photoshop, the selection, alpha channel and mask mask are actually the same. When you make a selection in Photoshop, the program treats this selection as a grayscale image, where the selected part is white and the unselected area is black. This black area is the digital overlay strip that covers the unselected parts of the image; white is the uncovered part that is used for drawing. The most powerful feature of a digital mask is its relationship to color grays: You can also partially select pixels in an image, and these areas are described in grayscale. The weaker (ie closer to white) the grayscale of an area; the more pixels are selected. In general, making the edge of a selection mask gray (or anti-aliasing) produces a softer gradient between black and white areas. Quick Masks There are several ways to observe the visual description of a constituency. One is the quick mask mode. Click the quick mask button at the bottom of the toolbox or press the Q key to switch to this mode. In quick mask mode, the overlay strip is colored (usually red to remind us of the history of red film), and the selected area is transparent rather than white. Since Photoshop's common selection tools are not very precise, I prefer to use the fast mask mode to make selections in addition to the most basic rectangular selections. You can edit the selection by editing the quick mask - you can use drawing tools, filters, etc. on it. Don't worry about drawing your constituency using conventional selection tools. Switch the image to quick mask mode, draw the selection with various brush tools, and press Q to exit the quick mask mode. Observe the traces around the area you draw. Channels and Layer Masks (Masks) Another way to get a visual representation of a selection is to save it with an alpha channel. Don't be intimidated by the word alpha, it's just a grayscale channel created outside the regular CMYK or RGB channels. (See "Choose from Channel") -- It stores the mask information. You can save a selection to an alpha channel by selecting Save selection from the Select menu or clicking the Save selection As Channel button at the bottom of the Channels panel. When removing the constituency, the quick mask does not exist. You can put alpha channels in files and reload them later as constituencies. You can also save the selection as a layer mask (see "Making layer masks"). When you select Add Layer Mask from the Layer menu, you tell Photoshop to add the mask to the layer so that the specified area is opaque. Then, the resulting mask is only associated with the selected layer. In this way, you do not need to delete the area on the layer - because the layer mask is not destructive. So, if you want to change your mind, the original layer is still intact. Selecting Techniques Even if you know the usage of the Photoshop selection tools, there are still many new ways to use them more effectively. Magic Wand Select Positioning If you are zooming in a rectangular or elliptical selection area and find that you can't accurately position the origin to the correct position, don't worry, hold the mouse button down, and press the space bar to move the entire Select and reset the starting point. Release the space bar to continue zooming in on the selection area. Choosing a Hidden Area In Photoshop 5.0, you can use the Lasso tool's select drag function to select multiple images outside of the image border -- hiding them from the gray canvas around the file. Lasso If you want to draw a line when using the lasso tool, press the Option key to release the mouse button (drag) to draw a line. To re-create the free outline, press the mouse button and release the Option key. Magic Stick Selection People generally use magic wand tools to select the (large) blocks in the image, but sometimes it is easier to use the Magic Wand tool to deselect fields. Drag a rectangular marquee onto the larger part of the image. Hold down the Option key and click the magic wand tool to cancel the unwanted selection. Fast color transitions It is often useful to change the quick mask red to something more noticeable - especially if your image contains red. To do this, you can double-click the quick mask icon at the bottom of the toolbox to change the color and opacity settings in the Quick Mask Options dialog box to implement it. Under normal circumstances, the transparency is set to 70% to 80%. One-step loading: Here is a shortcut to load the channel into the constituency: (Mac) Press and hold the ¤ button to click the channel on the Channels control panel. You can also press and hold ¤ to click a layer on the Layer panel to load a layer's transparent mask (the transparent area of ​​the layer). Should you buy a Plng-in? After trying out the selection tools and techniques mentioned in this article, do you think it would take too much time to make a good constituency? You might consider buying a commercial Plng-in to make your choice. It's easier. For example, Extensis's Mask Pro is worth $300 (800/796-9798), Chroma Graphics' Magic Mask is worth $100 (888/824-7662, WWW.chromagraphics.com) and Ultimatte's Knock Out is worth $495. /993-8007, WWW.Ultimattle.com). Each Plng-in has its strengths and weaknesses, so ensure that the selected Plug-in meets the requirements of the job. Time is value, so a Plng-in should be able to respond quickly. But be as patient as possible - it takes time to make a good constituency, and the more detail the constituency has, the more time it takes. With a little practice, you can easily and skillfully create selection fields and make Photoshop's powerful digital masks work for you. Shrinking and Extending Edges Don't expect to use a tool to make a good selection. The magic wand and Photoshop 5.0's magnetic lasso tool is a good example: both are first to determine a sufficiently precise range to create a selection. Then we need to perfect it. Because the biggest problem in the constituency is the edge overflow, a good trick is needed to shrink or expand the constituency - making it even smaller or larger. The Conrtact and Expand options in the Modify submenu under the Select menu have quite good results, but they are usually somewhat rigid. Here is a way to replace it. 1 First, use the magic wand tool to draw the edge of the light bulb to get a rough selection field. (A) However, when we switch to the fast mask mode, it can be seen that the edge overflow occurs when it is enlarged. (B) (Quick Mask Mode is one of the best ways to eliminate edge overflow). 2 In the fast mask mode, using a Gaussian blur filter to set the radius to 1 or 2 pixels, the edge overflow immediately weakens. But this is just a meaningless step to continue. 3 Now open the Levels dialog (press ¤-L) and drag the middle gray slider to the right or left. Make sure the preview check box is open so that you can see the rapid mask shrinking or expanding as you adjust the slider. Happening. Drag the slider mask to the right to shrink and drag the slider mask extension to the left. When you drag the slider to about 3/4 of the length, the edge overflow disappears. Then exit the quick mask mode, this selection has no edge overflow at all. Choosing from the Channel One of the biggest advantages of using equivalence selection fields and channels from Photoshop is that you can use the information in the channels to make a high-level selection. There are many different tricks here, including using High in the alpha channel.