Photoshop 104: Digital Flash Fill

Introduction: Photoshop 104: Digital Flash Fill

About: Every now and then I come up with a unique idea. And then I find someone else has already thought of it . . . which is AWESOME! Who knew there were so many kindred spirits on the web! YOU GO all o' us!

This instructable will show you how to create a digital flash fill for your underexposed family pics. The process can be automated, which allows you to adjust entire video sequences.

If you appreciate this instructible, please visit my blog for more ideas:

I use Photoshop 6.0 (since it's the only copy I own). Your mileage may vary with other paint programs. (Cricket paint anyone?)

Alright, why would you use a digital flash fill? Well, if there are some parts of your image that are very dark, like say, the face of your daughter, you could lighten it to a usable tone. Not only that, but this method is a semi-automatic, painfree way to lighten dark parts of an image.

Step 1: Duplicate Your Background Layer

Duplicate your background layer by dragging the layer name to the "new layer" icon at the bottom of the layers palette.

You should now have a duplicate layer named "Background copy."

Step 2: Blur the Duplicate

Apply a Gaussian blur to the image (Filter>Blur>Gaussian Blur).

Adjust the radius of the blur until no fine details can be seen, but the image is still barely recognizeable (i.e. I think I can still call that a person . . .).

Do not try to copy the numerical values you see in this example. The values change depending on the size of your picture, and so you'll have to eyeball it yourself.

Step 3: Invert the Duplicate.

Now invert the blurred duplicate by hitting Ctrl+I on your keyboard (what is it, Command+I on a Mac?) or by going to Image>Adjust>Invert.

Change the layer blend mode to "soft light." The "soft light" blend mode is a special proprietary Adobe blending mode that nobody I know really knows how it works. It will be just fine for lightening shadows for us.

Step 4: Adjust the Opacity

Now you should have an image that's actually a bit too bright in the shadows and looks quite funny. Adjust the layer opacity to correct this.

A good rule of thumb is:
If you look at your final image and can tell that it has been adjusted in Photoshop, you've done too much adjusting.

In this case I think the left half of the baby's face was a bit too bright, so I toned it back a bit.

That's pretty much it! For your convenience, I've automated these steps and put it into a Photoshop action set below.

Just save it in your C:\Program Files\Adobe\Photoshop 6.0\Presets\Photoshop Actions\ folder, or wherever other .atn files can be found on your hard drive.

If you want to tweak the flash fill, you can paint a layer mask like in the next step.

Step 5: Tweak It! Paint a Layer Mask

For the unwashed Photoshop masses, a layer mask is a black and white image where black is transparent and white is opaque.

You can use it to selectively control what parts of the layer are visible without damaging the actual layer data.

So, select a paintbrush, adjust it's opacity, and make sure your paint colors are black and white. Then just paint on your layer.

You should see subtle lighting changes where you paint, revealing the underlying layer.

Step 6: Behold What Your Work Hath Wrought!

Now compare your work to the original by clicking the eye icon next to the duplicate layer.

Hope this helps!

Happy 'shopping!

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    5 Discussions


    10 years ago on Introduction

    It's very useful, but you can improve it without taking a lot of job and simply. In the final result she looks a little bit green.


    13 years ago

    or you could get the same effect much more easily and quickly by making a selection around the face, feathering the edges, and adjusting the curves on the value channel, and not wash out the rest of your image along the way...


    Reply 13 years ago

    You know, I was a bit depressed this morning when I read your comment, because I was hoping someone would find this useful. But you bring up a good point for this picture about just selecting the face. It wouldn't be practical for most pictures I adjust using this method, though--the selection would be much more complicated. However, I cannot adjust a "value channel" in Photoshop unless I convert to Lab mode first. Do newer versions of Photoshop always give you acces to the value channel? Anyway, the action I wrote is really fast and combines all these steps into one easy to use package. *sigh*


    Reply 13 years ago

    Hey, I wasn't trying to get you down! Its still a good instructable and can work well (probably better in some situations), I'm just saying there are other, possible easier ways to do this. Its all about the specific photo. some will benefit more from this technique, and others better from mine. Your technique is much superior when you have way too much contrast between you highs and lows, since it effectively even out the contrast. My techniques would be better when you have an otherwise well-exposed photo with a shadow over a face or some other important detail. As for adjusting the value channel, I'm working in the GIMP, which lets you adjust the value channel by selecting "Tools>Color tools>curves" I'm not sure what the equivalent is in Photoshop, but I'd be surprised if you can't adjust something like this.


    Reply 13 years ago

    I usually only use the action I've saved without a mask. It's about 2 secs to use. Click. Drag. Click. Drag. As for washing out the rest of the image, a few of the problems with a lot of digital photography are too much saturation, not enough dynamic range, slow shutter speed in available light. Which usually leaves you having to use a flash, or end up with a blurry picture. In this case, with so much contrast due to the sunlight streaming in the windows, I had overblown highlights and pitch black darks with way too saturated colors in between. So the washing out was just fine with me.