The Magic of Masking – Unlimited Undo

No Masking No Photoshop, Know Masking Know Photoshop! This basic skill will make PS much more friendly to you. Check Why and How of Masking.

Lets take a case, you have a photograph in color as well as in black & white. And you want an edited image having Right half to be colored and Left half to be b/w.
If you are not familiar with masking then you will use eraser or do some selection and delete.

Image Courtesy: Albert Einstein, Summer 1939, Nassau Point, Long Island, NY,Colorized by Edvos on Reddit | Paul Edwards

Step 0. The common approach.
Place black white layer above color layer. Lets delete right half of black white layer to reveal content of layer below. This way we achieve our goal. But as you see in 3rd slide the contents of black white are lost (Half Transparent). You can Undo (Ctrl+Z) to get it back. But as we all know Undo has its own limits. What if after 100 steps later, you wish to have 75% Black & white and rest 25 colored. Maybe at last moment you feel like having Einstein in Black and white and rest in color. You can’t undo any changes once you have closed a file!

This is where MASK will be your saviour. Its not UNDO but an alternate and a good one.

Lets see for this case, how masking helps.

Step 1. Hiding.
Select Black White layer. Click on Mask icon on bottom of layer window. Now you see the White Mask is selected and not the Layer Box. You can see in second slide Layer Box selected and not the White Mask. So whenever we say work on mask, make sure White mask is selected and not the Layer Box.

Now, lets take a Brush(B), Round Hard and set color to black. Select White Mask and start using Brush from right part of sheet.
You can see wherever you use Black brush, the contents of Color Layer are revealed. Also you can see White mask now has black area in it. Use brush on Right half of sheet after selecting White mask.
We have now achieved our goal. Right half colored and Left half be b/w.

This is How a mask work. In Mask Box, any portion in Black hides the contents of masked layer and any portion in white keeps the masked layer contents visible.
So mask only hide or unhide the layer contents and never alters any contents in it. This way you can make changes(alternate to Undo) at any time by using White Brush to Unhide and Black Brush to hide contents of masked layer.

Step 2: Unhiding.
So let us try 75% of left to be colored. Select Mask. Change color of brush to white and start using brush from centre of sheet towards right. You can see all the changes to mask. Wherever the mask turns white, layer contents are visible and wherever black, layer contents are hidden.

What if you use any color other than black or white?? Well mask will consider any other color to be some type of grey. And wherever a grey color is used, it will effect the opacity of layer contents

Step 3: Layer content opacity.
Now what if you use any color other than black or white. Well mask will consider any other color to be some type of grey. And wherever a grey color is used, it will alter the opacity of layer contents

Change brush color to red. But you can see it does not change to red but a grey. start using brush from centre of sheet towards right.
You can see in Mask box grey color and wherever the mask is grey, layer contents have transparency in them.

Step 4: Other Tools.
Now check how a black and white gradient works. It gradually hides the contents of masked layer.

Another Example.Lets take a windows wallpaper and a black & white version of it. Apply mask by clicking mask icon. Now select Magic Wand(W) set tolerance around 20 and carefully select layer icon and click on leaf 3-4 times here . Once it is selected, make sure the background color is black(press D)
Now carefully select Mask and do Foreground fill(Alt+Backspace). And you see a black patch on mask and color image below revealed.
In case you want this leaf to be B/w and others colored,select mask and Invert(Ctrl+I). This replaces all white color with black and vice versa.

So start using layer masks from today. A mask gives you freedom to experiment. It saves your precious time. Happy Masking ahead 🙂

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