Making masks using AcuMask Tutorial

AcuMask© Tutorial

Building a Density Mask with AcuMask is fast and easy.
Follow these simple steps and you can't go wrong.

Density masks are required anytime you want a filtering or corrective effect to vary with the luminisity (highlight/shadow) of the image.

For example -- if you want to apply more "Noise" to the highlights than the shadows
--- use a Density Mask. (p.s. an even better way to add noise is to use "AcuNoise")

This cute little pixie is my granddaughter Emily.

I'm going use this image to show you how to build a density mask using Acumask.

Then I'll add a texture effect to the image that will be filtered through the mask. (the highlights get more of the effect than the shadows).

Step One

To begin we need to duplicate our image to a second layer "Background copy".

AcuMask will not work on a "background" image.

Step Two

Next select the AcuMask filter and click the Density Mask and Invert Mask checkboxs. With the Dark Range set to "0" and the Light Range set to "255", move the scrollbar for "Amount" to about "50". This gives us a medium density mask.---

Click Apply

Our efforts so far have resulted in this image on layer 2.
-- a gradient suitable for making a density mask.

Step Three

"Right" click on the Channels pallet and then the "Green" channel so it becomes highlighted -- like the example.

Check each color channel and pick the one you want. For this picture the "Red" channel was too washed out and the "Blue" channel was too dark.

Step Four

When you "Right" click on the "Green" channel a selection list will appear. Choose "Duplicate" and the screen shown on the right will open.

Enter a name for your mask "Density Mask". ---

Click OK

Step Five

Now your channels pallet will look like this example, with a new channel called "Density Mask". This new channel is in fact a "Density Mask".... That wasn't so hard was it?

To apply the Density Mask -- click on the "Density Mask" channel while holding down the "Ctrl" key....

Step Six

Now switch back to the "Layers" pallet and hide the second layer by clicking on it's eye icon.

Then select the "Background" layer.

Selection made from a density mask made with AcuMask

With the "Background" layer selected and our Density Mask applied, the image should look like this example.

In this image the "Light" areas are mostly transparent and the "Dark" areas are mostly opaque. Look again at image from "Step Two". The Dark areas are "masked" , "protected" or "NOT" selected. Conversly the Light areas "ARE" selected.

If you consider an area selected with the Lasso Tool, the area "outside" the selection area is actually "masked" and cannot be changed. The area "inside" the selection is "NOT" masked and can be changed.

Density masks vary in strength depending on the lightness or darkness of an image. Therefore some parts of the image are more selected than others. From a "mask" standpoint, some areas are more transparent than others.

Most paint programs only show a selected area when 50% or more of a pixel is selected. While a Density Mask may cover the complete image a lot of it will be at less than 50% selected, therefore a paint program only shows part of the mask. This is a case of "What you see is not what you get". ---
No matter how much of the Density Mask is showing it will still work properly.

Step Seven

Now we can apply the effect we want through the Density Mask.

In this example I've applied a texture I found in Photoshop under Filters/Sketch/Note Paper. These are the settings I used.

The image on the left shows the final results of our efforts.

As you can see the "Note Paper" filter has been added more to the lighter areas than the darker areas.

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