Photoshop can be a terrific tool for editing photos but can also be quite intimidating and complex to newer users. Often times, new users of Photoshop don’t realize there are often several different techniques to accomplish the same result and more often than not, resort to one of the canned filters to achieve something that is better left to using a layering technique. My hope here is to give newer Photoshop users a quick introduction to some layers techniques to fix some of the most common photo problems.
Too dark or too light?
When you first pull up your photo in Photoshop, you often get a sense from just looking at it that it is either too dark or too light. Sometimes it might be just right but I have found over the years that this happens far less frequently. If you can’t seem to figure out if it’s too dark or too light, you can check Photoshop’s Levels histogram to see the distribution of tones in the image. This is essentially a chart with dark tones on the left and light tones on the right. If more of the chart is on the left, the darker the image is and vice-versa. In some cases, it may be intentional for the image to be darker or lighter but if in your case you want to fix the problem, one of the easier and non-destructive ways to do it is to use the screen/multiply layer technique.
Non-destructive darkening of a photo
If your photo is too light and you don’t want to get into the business of using the advanced and complicated levels method of adjustment and find the results of using the contrast/brightness adjustment less than desirable try this: with the photo loaded in Photoshop click on ctrl-J(PC)to duplicate the current layer which should be the one with the photo in it. Select the new duplicate layer and change it’s blending method on the layers palette from “normal” to “multiply”. You image should now be considerably darker while maintaining the tonal qualities of the image. Now you can adjust the amount of darkening by varying the amount of opacity for the multiply level. The lower the opacity, the subtler the effect becomes.
Non-destructive lightening of a photo
For photos that are too dark, the procedure is basically the same except that instead of changing the blend mode of the new duplicate layer to “multiply” you change it to “screen” which will lighten the image while maintaining tonal properties. Again, lowering the opacity of the new “screen” layer lessens the effect.
Make it so
Once you have lightened or darkened your image in this manner, you can go back and adjust the effect at any time by varying the opacity of the layer. If you make any changes to the base layer itself especially ones involving adding or removing details you will have to toss the multiply or screen layer and redo the effect. At some point, when you are happy with the effect and anticipation of other touch-ups, you will want to merge the duplicate layer into the photo base layer it was copied from by clicking on the Layers palette menu button (the little round button with the play arrow up near the top-right corner) and selecting merge down. Once his is done, the changes are permanent and can only be undone using the history palette or undo. At this point, you can continue with your photo editing.
Non-destructive sharpening the easy way
Once you have adjusted the overall tone of your image, you may want to sharpen it. In most cases, today’s digital cameras just don’t produce sharp images. That’s not the case every time but in most cases it’s true. Where this is a very basic introduction to some easy techniques for touching up your images, I won’t get into using the advanced tools like the unsharp mask. The standard sharpens and sharpens more filters are generally too harsh and offer you no control. I prefer using the high pass sharpening method since it produces far better results with more control and it’s really easy to implement and not permanent unless you make it so. Let’s get into it: Use the ctrl-J(PC) method for duplicating the original photo layer (usually the background layer). Select the duplicate layer and change the layer’s blending mode from “normal” to “overlay”. Don’t worry if the coloration looks weird, it will get better in a minute. Now click on the Filter menu and then down to the “Other” filter in the list. Choose “High Pass” (Filter>Other>High Pass). Now you are shown a preview picture of your image and a slider for “Radius”. Sliding this value up to higher values sharpens the image more. In most cases, a value between 1.0 and 5.0 is sufficient but you can see the results as you move the slider so play with it until the image is sharper without overdoing it. Click “Ok” to accept. If you are satisfied at this point, you can merge the duplicate “overlay” layer to finalize the effect.
Removing Color Casts
Lastly, if your photo has a more or less uniform color cast to it, say blue for instance, and you want to remove it without the hassles of the more advanced Curves, Levels and Color Balance features you can try this trick: create a new blank layer above your photo using the “new layer” button at the bottom of the Layers palette. Click on the Edit menu and select “Fill” (Edit>Fill) or hit shift-F5(PC). On the now present Fill menu, select the drop-down list for “Use:” at the top under “Contents”. Select 50% Gray to fill the entire new layer with 50% gray. Change the blend mode for the 50% gray layer from “normal” to “difference”. Don’t worry about the weird look. Now click on the Layers menu and select “New Adjustment Layer” and on the next sub-menu choose “Threshold” (Layers>New Adjustment Layer>Threshold).
You are now presented with a New Layer dialog. Leave all the options including the “use previous layer to create clipping mask” option as-is. Just click “Ok”. Now you should be looking at the Threshold layer dialog which shows a black and white chart of your image and a slider. Make sure “Preview” is checked so you can see the effects on the actual image as you adjust the threshold. Adjust the slider all the way to the left down to a value of 1. As you do, the actual image should turn all white. Now carefully and slowly adjust the slider back to the right until the very first black dots on the actual image appear and immediately stop. Do not press “Ok” yet. Now hold ctrl-space(PC) to bring up the zoom in tool. Hold the tool over one of the black dots and zoom into it several times.
Release ctrl-space(PC) and the eyedropper tool should return. Hold the shift(PC) key which should change the tool from the eyedropper to the Color Sample Tool which looks like the eyedropper with a little target image in the top-left corner. Put this tool right over the black dot you zoomed into and left-click the mouse to put a little target (labeled 1) on the black dot. This precise little black dot represents an exact pixel in your image that should be neutral gray but probably isn’t due to the color cast. You may now hit the
“Cancel” button on the threshold adjustment dialog to avoid adding the new adjustment layer. You may delete the 50% gray layer you created. You should still be zoomed into the target you just dropped onto the image on what was a black dot, if not zoom into it now. Click the Image menu and choose the Adjustments option. On the sub-menu choose the “Levels” option (Image>Adjustments>Levels) or you may hit ctrl-L(PC). On the Levels dialog, you should see another black and white chart of your image. Make sure “Preview” is checked in this dialog as well. Near the bottom-right of the dialog are three eyedroppers, the left is for setting the image’s black point, the right is for setting the image’s white point, and the middle eyedropper is for setting the images neutral gray point. Click the middle eyedropper. Now move the eyedropper right over onto the actual image and precisely onto the center of the target you placed earlier. You should immediately see the effects of doing so and this should now have removed the color cast from your image. Click “Ok” if you are satisfied with the results. Please bear in mind that this technique doesn’t work in every case but is quite effective when it does and easy to tweak and or undo if need be.
Well, that’s it, just a few good layers techniques to get you going on your way. By no means are these the only tricks and I highly recommend doing some research and learn how to use the more advanced tools I mentioned since they offer way more control and much better results in the hands of a skilled user. Keep on Photoshop’n!