Masking in iColorama

Masking is a very common tool you will use every day in iColorama. There are two main reasons you will want to use a mask. One is when you are blending images, and you want to blend only a portion of one image into another image. Say, for example, you want to blend the sky from one to replace a so-so sky in another image. Or, say, you want to place a cat from one image onto the floor of another image in a composite you are building.

The other main reason you will be using masks is when you want to make a local adjustment to you image. Say you want to change the color of the eyes, or you want to lighten just the face, or darken just the background, or apply triangles to just one object in the image. Then what you will do is use a mask to confine the effect of the change to just those areas.

Here I will briefly describe how to do these kinds of masking. I will discuss the feature of iColorama called the Brush Mask. It is called that because you will make the mask by brushing. There are other ways of making masks in iColorama, but I won't deal them here. For an exhaustive discussion of masking or of any other iColorama functionality, I highly recommend Jerry Jobe's blog Enthusiasm Noted.

The type of masking I describe here is what I use frequently in my tutorials.

To create a mask in iColorama, open an image.

Let's say we want to change the color of the girl's eyes. Go to Tone/Tint, use the first preset, and select Screen from the blend modes at the bottom right. (This is just one of many ways you could change the color, I'm just using these settings as an illustration.) You will notice, of course, that the color change affects the entire image, but we want to change only the eyes.

Don't apply yet!

What we need to do is use a mask. Do this by touching the Brush Mask button on the left of the image. This will bring up the brush mask bar, and the Brush Mask button will turn red.

We don't yet have a mask. But now touch the Invert button that you see in the middle of the Brush Mask bar. You will notice that the image of the girl goes back to the original color.

Now we do have a brush mask, but you can't see it because it covers the entire picture. That means that the entire picture is being "masked," that is, prevented from being affected by the Tone/Tint change that we made.

In the next step you'll be able to see the effect of the mask.

Now we want to zoom in so we can work on the eyes. Touch the Zoom button on the left side of the screen. The Zoom button should turn blue. This means that Zoom is enabled. While Zoom is enabled, you can can use your fingers to zoom in and out. Zoom in to enlarge the eyes.

Now touch the blue Zoom button. The Zoom button should turn black again. This means that Zoom is disabled, and any touch you make to the screen will affect the brush mask, rather than zooming.

Now set a small brush size, using the Brush Size slider on the Brush Bar. This is the size of the brush you will be using to brush your mask.

Now we can start painting the mask. Carefully paint just the girl's eyes. As you paint, you will see them change color. This is the color we chose in Tone/Tint, remember?

Now apply.

If you are happy with the eyes, you could now remove the brush mask. But first I want to change the contrast of the eyes. So, leave the brush mask in place. Now, select Adjust/Levels. Move the Min Input slider part way to the right. You should see the eyes become a deeper shade of red. You will notice that the Levels adjustment does not affect the rest of the image. That is because we still have the brush mask in place.

Now apply. Let's assume we are happy with how the eyes look. So now we can remove the mask. To do this, touch the Remove button on the brush mask bar. And now touch the red Brush Mask button to hide the brush mask bar.

If you think you might need to change the eyes again, instead of removing the brush mask right away, first touch the Export button on the brush mask bar. This saves the brush mask as a black and white image in your camera roll. Now you can remove the mask. The next time you want to edit the eyes, open the brush mask bar and touch the Import button on the brush mask bar. Your camera roll photos will come up, and you can select the black and white image that is the mask for the eyes. Now you can make whatever changes you want to the eyes without affecting the rest of the image.

If while you are painting the mask you make a mistake, you can correct it. You may have noticed that while you were painting the mask, the Paint button on the left-most side of the brush mask bar was blue. If you make a mistake while you are painting, touch the white Erase botton that is just to the right of the Paint button. The Paint button should now turn white and the Erase button should turn blue. When you are finished erasing, touch the Paint button again to continue painting. The Paint button will turn blue again and the Erase button will turn right.

There might be times when you want to change the opacity of the mask after you have painted it. To change the opacity of the mask, touch Set on the brush mask bar, touch Adjust on the window that pops up, and use the Full Opacity slider -NOT the opacity slider, which just affects individual future strokes. As you change the position of the Full Opacity slider, you will see your local adjustment fade in and out. When might you want to do this? After all, you could have done the same thing by using the opacity slider on the bottom left of the screen. The time when you want to change the opacity of the mask is when you are already using the main Opacity slider to affect the entire image, but you want to effect to be either stronger or weaker for the local area you are masking. For example, maybe you want to tint the entire image red, but not at 100% opacity. You would use Tone/Tint just as we did above, but with set the overall opacity at, say, 75%. Now you'll paint your inverted brush mask over the eyes, just as we did above. But maybe you don't want the eyes at 75% red tint. You can set a different opacity for the brush mask. I've done this in a couple of my tutorials, but you will probably only occasionally use this feature.

In the example above, when we were painting the brush mask, we used the default brush. The default brush is a soft round brush. If you want to use a different brush, you can touch the Brush button on the brush mask bar, and the usual selection of brushes comes up. Why might you want to use a different brush? Maybe you want a brush with a hard edge, if you want a very hard transition between the masked and unmasked areas. Or maybe you want an interesting shape. You could choose, say, a bird shape, and then use the brush to stamp a bird-shaped hole in your mask, rather than an eyeball-shaped hole as we made in our example.