Cute and funny story of the week: My sister home-schools her kids, and her daughter is having a bit of trouble with math. Because her daughter has a hard time thinking abstractly, my sister often has to use stories to help her learn. Here’s the equation that they were working with:

2A+7=19

Sister: Do you know how to find out what A is?

Niece: No.

Sister: Ok, well we want to know what A is but it is hiding because it has too many friends around it. So we have to get rid of the friends. So we want to get rid of the friend who is by the plus. Which one is that?

Niece: 7

Sister: Good, now what we do on the left side of the equal sign, we also do to the right side. So if we want to get rid of the 7, we do the opposite. What is the opposite of plus?

Niece: Multiply!

You can see that they have a lot to work through.

But this almost pointless story really does kind of relate with today’s topic, because Screen Mode is the opposite of Photoshop’s Multiply Mode. Let’s start with what Photoshop says:

Looks at each channel’s color information and multiplies the inverse of the blend and base colors. The result color is always a lighter color. Screening with black leaves the color unchanged. Screening with white produces white. The effect is similar to projecting multiple photographic slides on top of each other.

Remember how Multiply Mode was really great for helping you color line drawings, because the “white” areas ended up acting transparent, allowing bottom layers to show through? With Screen Mode, the opposite is true; black areas act transparent, while white areas are “solid.”

Here’s an example:

And let’s overlay this paw-print layer on top:

Setting the paw-print layer to screen mode gives this result:

The lighter areas “lighten” the image a lot (resulting in some almost-white areas), while the darker areas allow the base layer to show through.

One often-used practical application of Screen Mode is to “lighten” underexposed (too-dark) photos. Here’s my example — I start with a photo of a baby’s hand. She was in the shade and asleep, so I didn’t want to use the flash. But she was also being rocked and jiggled around (to keep her asleep?), so I didn’t really want to mess with slower shutter times, either. The overall picture ended up pretty dark:

By duplicating the layer and setting the top layer to Screen Mode, the image is lightened significantly:

(Remember that Screen Mode will only make things lighter overall; but also remember that darker areas will be lightened “less” so you don’t lose the contrast.)

If you want, you can even duplicate the layer again, also set to Screen Mode, to further brighten the picture. You can also adjust the opacity of the layers to adjust the effect.

And here’s the final result:

Side note: When it comes to lightening/darkening images, there are a lot of different ways to do it in Photoshop. You may play with levels and curves, try out different blending modes, play with different color channels… Using Screen Mode is definitely not the only way to lighten an image, nor is it definitively the “best” way. However, it is a “quick” way, and for some projects, it might be all that you need!

Now for some of you overachievers, here’s another neat way that you can use Screen Mode: Add a cool, subtle lens flare to an image. You’ll even get a sneak preview at the next topic: Color Dodge!

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• rae

Multiply :DD You made me laugh :) Announcing The best joke of the week.

An addition to your side note: with Photoshop CS you can even play with the handy shadow/highlight tool.

Keep up the good work!

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