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© 1999 by Mike Bresciani. All Rights Reserved.
When you make a mask it gets drawn to an Alpha or Mask channel as a grayscale image. Normally we create a mask only using two colors, Black & White. Then this mask channel is used to determine the opacity of the mask. To see this better, open a new image and create a mask using one of the mask shape tools. Now look at your Channels Docker either by clicking on the channels tab on your docker or by using the CTRL-F9 shortcut key. You will see a channel named Current Mask. Notice how the white area in the channel is the same as your mask. Now save the mask, menu Mask | Save | Save as Channel. Go back to the Channels Docker, if you aren't already there, and select the channel you just saved. You will see a black and white representation of your mask in your image area. When used as a mask, the white area is completely transparent, and allows you to modify the image underneath it. The black area has no transparency, and prevents you from changing anything.
However, we're not limited to just 1-bit or black & white. The channels in Corel PHOTO-PAINT are 8-bit channels and they allow you to have up to 256 different shades in the channel. As an example, you use this capability every time you feather a mask. To see this, click on the RGB channel then go back to the Objects Docker. Go ahead and feather the mask you made a few minutes ago. Menu item Mask | Shape | Feather. Use a feather of 10-20 or so, save the mask to a channel. Now go back to the Channels Docker and look at the mask. You can see that the edges have been faded to various degrees of gray. Since black is totally opaque and white is transparent, all the grays in between represent different levels of mask transparency. So a grayscale mask would give you 256 different degrees of transparency. This can be used to get some incredible results.
If you want to follow along you can find the image at right in the /exercise folder of the CorelDRAW 8 or Corel PHOTO-PAINT 8 CD #1. The filename is 569057.wi.
Notice how the detail is lost in the darkness of the shadows.
If you try to make the shadow area bright enough to see the detail, you will lose the detail in the highlight areas like the boards in the background or the plate of nachos (see example below). Normally you would spend some time creating a solid mask around the light areas to prevent this. There is a quicker, easier, and more gentle way, that works in a lot of cases. Mask it with a grayscale mask.
Copy the image to the clipboard. Select Paint on Mask by clicking on the icon, or selecting it from the Mask menu. (This allows you to change the image in the mask channel without having to switch to the Channels Docker). Paste the image in as a new selection. Turn off Paint on Mask. Invert the mask, by clicking on the icon or by using menu item Mask | Invert. Now make your brightness adjustment. I used levels to adjust mine. As you can see the highlights don't take as much of a hit this way, and you can still get some decent detail from the shadowed areas.
What we did was make a mask from the image itself. To better see the mask we created, click on the Paint on Mask icon again or select Paint on Mask from the Mask menu. When we inverted the mask, this put the lighter areas of the mask over the darks areas of the image. And since the lighter areas of a mask are more transparent, inverting the mask had the effect of making the mask over the dark areas of the image more transparent. This allowed us to make a bigger change to the dark areas, at the same time making a smaller change to the lighter areas of the image.
Let's look at another use for the grayscale mask. I would like to remove the bride from the picture and put her over a different background. The problem is the veil. We won't be able to see the new background through the veil, which will ruin the effect.
This use of this mask technique works best against a solid background. If you look real close at the images at the end of this section you should notice a piece of the brass handrail that got picked up in the lower left corner of the veil. With a little extra effort the clone brush could be used to clone a section of the dark area from another part of the veil to cover this prior to copying.
This image comes from the CorelDRAW 8 CD #3 in the /photos/spec_occ folder. The file name is 724091.wi.
Create a mask from the image using a copy of a channel and adjusting the levels. A technique that I covered in my earlier tutorial, Fun With Photos - Selecting Objects Part II. I used the Blue channel for mine. Hang on to the image after you make the mask. We are going to modify the image to create a new mask.
Select the mask image and adjust the opacity so you can see the underlying image. About 50% should do it. Make sure you can clearly see the transition from the dress to the veil.
Select the Paint Tool. Use a solid brush and a paint color of 20% black (light gray). The amount of gray you use will depend on what you are masking and how transparent it needs to be. Darker grays will be more transparent, lighter ones less.
Load the mask you just made so you don't have to worry about going outside the edges. Now make sure the image you used to make the mask is selected and paint over the areas of the veil you want to be transparent. If you miss and get some gray on the dress, just paint over it with white. Watch out for the border near the bottom, it should be solid. Also, don't forget to paint the veil on the other side of her face. For some, it may be easier to create a path around the area you want to color gray, create a mask from the path, and fill the mask. See Fun With Photos - Selecting Objects.
When you are done you should have an image similar to the one at right. Now let's make it into a mask. Turn off any masks you may currently have open, make sure this object is active, and copy it to the clipboard. Select Paint on Mask by clicking on the icon, or selecting it from the Mask menu. Paste the image in as a new selection using menu Edit | Paste | New Selection. Turn off Paint on Mask. If you look in the Channels Docker you will see that you have created a new channel called 'Current mask' that consists of the image you just created. Go ahead and save this mask.
Once you get the mask set, feather it a little. I used an inside feather of two pixels. Now copy the bride to the clipboard. Then make a new document from it using menu, File | New From Clipboard. This will give you an image with one object and no background. Go ahead and create a background using menu, Image | Create Background. Now fill it with whatever background you prefer, and you will be able to see it through the veil as shown in the two images below.
Let me show you a couple of more ways to use grayscale masks.
The below left is what I loaded in as a mask. If you want, save this one to disk and use it for the following examples.
Create a new image. Make it 5 in by 5 in with a dpi of 72. Now load the angel image as a mask. Use menu, Mask | Load From Disk. Then fill the image with a fill pattern.
For another variation (as shown at right), undo the fill, and invert the mask. Then fill it again.
Okay, now undo the fill again. Select the Image Sprayer. Choose the cloud image list. Now paint with the sprayer. Clear the mask area using menu, Edit | Clear. Paint one or two clouds in the angel again. Don't overdo it. Turn the mask off and paint a few clouds around the angel.
Copy the image to the clipboard. Activate Paint on Mask. Use menu item Edit | Paste | New Selection. Turn off Paint on Mask. Then Apply the Alchemy filter with a style of Smoke.
Activate Paint on Mask. Apply a radial fountain fill that is dark in the center and light on the edges. While editing the fill, click on the center of the preview of the fill and drag the center point to slightly right of center, to correspond with the position of the duck. Apply the fill. Turn off Paint on Mask. Apply the Emboss filter with a depth of 2 and a level of 125.
I don't know about you, but I kind of like the way it turned out.
There is certainly opportunity for a lot of creative expression using these techniques. I have only touched the surface, but hopefully I have given you a few ideas for your own creations.
Using CorelDRAW to Make Quilting Blocks · Creating a Painted Effect from a Photograph · Using Grayscale Masks in Corel PHOTO-PAINT · Adding Color to Black and White Photos With Corel PHOTO-PAINT · Fun With Photos -- Selecting Objects Part II · Fun With Photos -- Selecting Objects · Using Corel PHOTO-PAINT's Image Sprayer · 3D Web Buttons with Rolled Edges Tutorial · 3D Web Button Tutorial
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