Category Archives: Photoshop Tips

Tips and techniques for editing photos using Photoshop.

Filter Forge Photoshop Plugin Review (And Giveaway)

Filter Forge - an advanced Photoshop plugin

[tweetmeme]The folks at Filter Forge contacted me about reviewing their advanced Photoshop plugin software. I’m always interested in checking out new things, so they provided me with a review license of the software and I started exploring it. I must admit that it’s an impressive piece of software.

Read on for my review and be sure to check the details at the bottom about the contest and prize giveaway. This review contains affiliate links.

WHAT IS FILTER FORGE?

Filter Forge is a Photoshop plugin with a huge variety of filter and texture options for photographers and designers. The plugin contains over 7500 textures and filters, most of which are user generated. And that’s another key feature of the software — you can generate your own filters and make them available to other users.

The real strong point of the Filter Forge software is the extensive library of user generated filters and textures. There is a seemingly endless supply of options out there, and the library is constantly growing. The folks at filter forge also offer an incentive to create and promote new filters, handing out reward points for the more popular filters created. Those reward points can earn you discounts and free software.

There are two sides of Filter Forge — textures and effects. If you’re into applied textures, this software will keep you occupied for quite a while. At the time of writing this review, there are nearly 4000 textures available. Filters, or creative effects, are also in abundance with over 3600 options. You can search and browse through the filters at the Filter Forge website.

WHAT CAN YOU DO WITH IT?

Applying filters is relatively simple. You start up Photoshop, pull in your image, and start Filter Forge from the Filters menu. Once inside Filter Forge, you can select the textures or effects you want to apply, check out a few presets, or modify the settings for that particular filter. After you apply the filter or texture, you’re back in Photoshop. That’s pretty much it.

Creating filters is a little more complicated, but the interface is still fairly simple. You can start from scratch or modify an existing filter by using the components available in the filter editor. These components include things you would find in Photoshop: brightness, gamma, hue, saturation, threshold, invert, levels, curves, gradients, blurs, blends, and a whole bunch of other tools you won’t find in Photoshop. The process is very similar to creating a Photoshop action, but more visual and self explanatory.

Enough talk, here are a few of my own photos with various applied filters. Click on the image to see the originals at Flickr.

MY FINAL THOUGHTS

This is certainly a handy piece of software for the folks that apply textures and filters on a regular basis. The sheer quantity of options is staggering. If you’re a “naturalist” with your photography, maybe this isn’t for you. But other photographers, and even graphic designers, should check it out if it sounds remotely interesting.

Filter Forge can be downloaded as a 30 day free trial with no other limitations (and check out the free plugin packs on the same page that don’t require the Filter Forge software). If you want to buy the software and continue to have access to the full library, you have three price options: basic, standard, and professional editions. The basic edition only allows you to use the filters, the standard edition allow you to create your own, and the professional edition has a bunch of other bells and whistles. Check the website for prices because they may change in the future.

WHO WANTS A FREE COPY?

Now for the fun part — I have three licenses for the basic edition of Filter Forge to give out! We’ll run this as a photo contest using the Filter Forge plugin (and if you don’t have Photoshop, you can use it as a standalone software). Here’s what you need to do to enter:

STEP 1. Download a free copy of Filter Forge and install it.

STEP 2. Choose any photo of your own and apply your favorite filter.

STEP 3. Email your photo to blog@epicedits.com. Size it to 1000px on the long edge, make sure to include your name, and tell me which filter(s) you used.

DEADLINE: October 10 13, 2010

One entry per person and the photo used must be your own. By entering the contest you only give Epic Edits the right to display your image as a contest entry no larger than 500px. You retain all rights to your photo.

After the deadline, I’ll size the images to 500px and post them here on the blog along with your name and the name of the filter used. I’ll choose the three winners myself (or I’ll have a couple of guest judges help me out).

A Simple Method for Creating Composite Photos

[tweetmeme]Composite photos are made up of two or more different images. There are several different types or styles of composites, but I’ll be focusing on just one in this tutorial.

The type of composite we’ll look at is made up of multiple images with exactly the same framing, exposure, and lighting. Using this method, you can add or subtract objects from a scene. Obviously, this isn’t something you want to do in photojournalism, but it does have applications in other sectors of photography.

Here are seven basic steps for creating simple composite photos.

1. CAMERA SETUP

First off, you need to use a tripod so each frame doesn’t move. To make your post-processing easier, you’ll want to shoot in manual mode if you can. This will give you the ability to produce multiple images with the same exposure (assuming your lighting situation is constant).

2. CAPTURE MULTIPLE EXPOSURES

Once you have the camera ready to go, take as many images as you think you’ll need. Then take a bunch more. You can always throw out the extras, but you can’t go back and get one or two more after you’ve taken the camera off the tripod. I shot 29 different poses for my example composite.

3. OPEN IMAGES

If you shoot raw format, just be sure to process the images with the same settings. After raw processing, open them all in Photoshop, The Gimp, or any other software that allows you to use layers and layer masks.

4. CREATE LAYERS

Choose one photo to be the base image for the composite. Place all other images in layers above that base image. We’ll be grabbing bits and pieces from these layers to create the composite.

5. MASK LAYERS

On each layer above the base image, add a layer mask and hide all or fill with black. The black layer mask will block out the pixels from that layer, so you should only see the base image at this point.

6. PAINT THE COMPOSITE

Now you can go back to each layer mask and paint white over the areas that you want to show. This could be the addition of objects present in that layer, or the subtraction of objects present in the base layer. If you need to see what’s in your working layer, press “shift” and click on the layer mask. This will temporarily disable the mask and show just the image. Press “shift” and click the layer mask again to enable it again.

7. FINISH POST PROCESSING

After you get the composite image looking good, you can either save it out as a new image or continue working with it in Photoshop. Any adjustment layers that are applied above the composite layers will act on the composite as a whole.

And here’s the finished product.

I See Three of Me

That’s about it… there’s not a whole lot to it. If you get the initial shots identical in composition, exposure, and lighting, the rest is pretty easy. Here are some other examples of composite photos.

Mirrored self-misidentification
Creative Commons License photo credit: eqqman

paradox v2.0 (1 of 2)
Creative Commons License photo credit: pochacco20

Composite
Creative Commons License photo credit: j-william

Kestrel Composite
Creative Commons License photo credit: markkilner

04/50 - everyday is a mindless routine.
Creative Commons License photo credit: eleven days into april.

bmx stunt
Creative Commons License photo credit: katiew

Too many babies
Creative Commons License photo credit: PhotoBlackburn

Anthony Equals Three?
Creative Commons License photo credit: Ben Chau

366 • 65 • Shadow monster
Creative Commons License photo credit: Pragmagraphr

Fool-Proof Photoshop Airbrushing for Dummies

Guest post by Alexis Bonari… A quick and painless way to “airbrush” a picture in Photoshop. I showed a method for digital airbrushing using Photoshop in a past article, but this method takes a slightly different approach.

[tweetmeme]Hi dummy! So glad you could join us today. Just kidding, just kidding. With the advent of Myspace, then Facebook, and who knows what’s coming next, the whole world has become an endless source of perfect skin and magazine cover worthy supermodels. Now that Photoshop is a verb and household name, you might as well get in the know and make yourself (or your girlfriend/boyfriend) uncommonly perfect.

Here’s what you do.

We’ll be using this image, available through Wikimedia Commons:
http://commons.wikimedia.org/wiki/File:Bangalore,_India_Model.jpg

Save it to your computer.

1. Open your image in Photoshop. ( FILE -> OPEN )

2. Immediately duplicate your image’s layer. ( LAYER -> DUPLICATE LAYER )

3. Make sure your new layer is selected, and then Surface Blur that layer, so that your image looks like this one. Play with the Radius and Threshold to achieve this effect.

4. Now, create a layer mask with this newly blurred layer, and make it set to HIDE ALL.

5. Select your paintbrush, make it big, and reduce its “hardness” considerably. Then change your brush color to WHITE (#FFFFFF).

What has happened so far? You will notice now that you are back to your original image. What has happened behind the scenes is that that blurred image is still there, only that it is now hidden behind the layer mask. This mask will only show parts of the image that are painted in white. So, your next step is where the fun begins!

6. Making sure that your blurred layer’s Layer Mask is selected, you will now generously paint over the areas you want to “airbrush”. You will notice that as you paint, the blurred image will start appearing. Be cautious to not paint over eyes and lips, as you will want their defined textures. You will also find it useful to change your brush size to accommodate around the eyes and lips or any other nooks and crannies that might need you to get in there. It doesn’t have to look perfect at this point. We’ll fix that in a minute.

7. This is what my layer mask actually looks like.

8. Now, with that all done, we’re going to smooth this out even more. Select your GAUSSIAN BLUR filter and blur stuff even more. I like setting it to about 5.0 pixels for this image.

9. Finally, making sure that your blurred layer is selected, adjust that layers Opacity, to blend the blurred effect with the original. In this case, I settled on 72%

Once your image looks the way you want it to, it is ready for saving or exporting for web, or whatever you would like to do.

Less than 10 easy and quick steps, and you’ll have your images looking like the pros! I knew you could do it. Great job!

Bio: Alexis Bonari is a freelance writer and blog junkie. She is currently a resident blogger at onlinedegrees.org, researching areas of online degree programs. In her spare time, she enjoys square-foot gardening, swimming, and avoiding her laptop.

Photoshop Technique: Digital Airbrush

[tweetmeme]Airbrushing is (or was) a process typically used to remove minor imperfections in portrait, model, and fashion photography (among other uses in photography). I’ll be presenting a digital airbrush technique in Photoshop intended to slightly smooth out skin textures in close up portraits. Sharp lenses and good lighting can produce very detailed captures, including all the small wrinkles and pores. Sometimes you just want to smooth out all those little things.

I’ve also created a Photoshop action to speed up the process described below. All you have to do is open up the original image and run it. The action stops at the filter dialogs and allows you to adjust them before proceeding. At the end of the action, you’re all set up and ready to start airbrushing.

DOWNLOAD THE DIGITAL AIRBRUSH PHOTOSHOP ACTION

I should also mention that I learned this technique from at least one or two other sites out there (can’t find the source for the life of me right now). I’m definitely not the originator — I’m just passing along my own interpretation of the process.

So here’s the image I’ll be working with… a very close-up and well-lit portrait. What you see immediately below is the final image after applying this airbrush technique. I’d show you the before image, but you wouldn’t be able to see much of a difference at this size.

Amazing Portrait of Merunisha Peel

A couple of things to remember before I get into it: don’t go overboard with the processing, experiment with the numbers to suit your image, and what I’m showing here is not the only way to do it. So let’s get started.

1. ORIGINAL IMAGE

This is a crop of the original image after being processed in ACR for exposure, contrast, white balance, etc. The crop is a 50% zoom so we can see more of the image while retaining some of the important details. Take note of the small skin wrinkles and pores — these are the things we’re going to smooth out a bit.

2. DUPLICATE BACKGROUND

When you open it up into Photoshop, duplicate the background layer. We need to do this because we’re going to apply some destructive modifications to the top layer, and we’ll be applying a layer mask later on. Essentially, we’re going to make a “new skin” that can be airbrushed over the existing image.

3. SMOOTH IT OUT

Now it’s time to make that skin into plastic. Apply the “Dust & Scratches” filter (Filter >> Noise >> Dust & Scratches…). Start with a 5px radius and adjust until you get something almost cartoon-looking. You want to get rid of the small details while maintaining the bigger details.

4. ADD BLUR

After smoothing out the little things, we want to add some blur to soften up the bigger things. Apply a “Gaussian Blur” filter (Filter >> Blur >> Gaussian Blur…). Again, start with a 5px radius and adjust until you lose that cartoon look. You want to soften the hard edges while maintaining some amount of contrast in the larger details.

5. ADD NOISE

This one is nearly impossible to see even at a 50% zoom — it’s very subtle. Apply a small amount of the “Noise” filter (Filter >> Noise >> Add Noise…). Start around 0.7px with a uniform monochromatic noise and adjust until you can barely see it at 100% zoom. You want to break up the plastic look just a tiny bit with some texture.

6. MASK IT

Now that you’ve completely destroyed the working layer, mask it all out. Add a layer mask and fill it in black (Layer >> Layer Mask >> Hide All). Now your image should look like the original because we’ve masked out the modified layer.

7. AIRBRUSH TIME!

Grab your brush tool, soften up the edges, set the color to white, put the opacity to around 10 or 20%, and select the layer mask we just created. Adjust your brush size to suit your needs and start painting in some of the fake skin. The key here is to do a little bit at a time while varying your brush size and edge hardness. Paint over the areas where you want to remove small details. You want to brush in a little more fake skin than you need — we’ll fix it in just a second.

The image above shows the mask applied to the image. You can see that we’ve removed most of the skin texture while keeping the details in the eye.

The image above shows the mask for the entire image. You can see that I focused mostly on the areas… in focus. I also made it a point to avoid the eyes, mouth, and hair. We don’t want to soften up these areas.

8. BACK TO REALITY

At this point, you probably have something slightly resembling a plastic doll. No biggie — we can fix it. Simply adjust the opacity of the modified layer until you bring back some of the original skin texture. I ended up with an opacity of 70%, but you’ll need to judge and adjust your own image based on how heavy you modified the skin during the airbrushing.

9. BEFORE & AFTER

As you can see from this split image, the final adjustment is not very harsh. The intent was to smooth out the very small wrinkles and skin pores visible in on the face.

And for those of you viewing this on the site, you can mouse over the image below to see an after and before effect. RSS and email readers will need to visit the site to see it (there’s a JavaScript mouseover making it all happen).

I don’t use this technique very often, but it’s a good one to know. Useful for close up portraits, but that’s about it. And don’t abuse it — soft and subtle is the key here. A bit of skin texture is actually a good thing!

Tone Curves: Final Tips, Tricks, and Things to Avoid

[tweetmeme]We’ve had quite a journey with this whole histogram and curves ordeal:

And now I’d like to wrap things up with a few tips, tricks, and things to avoid when using curves. It’s a fairly simple tool once you begin to work with it and understand it, but there are a few non-obvious items worth pointing out.

what lies within?
Creative Commons License photo credit: Fifi LePew

TIPS

We’ll start off with a few generic tips for working with curves, then we’ll move on to the some of the more detailed stuff.

TRICKS

Here are a few tricks for the ACR/Lightroom interface under the “Point” curve.

  • Hold Ctrl and mouse over the image to see where the tones lay on the curve/histogram.
  • Ctrl+click over the image to set an adjustment point on the curve.
  • Ctrl+select adjustment points on the curve to delete them.
  • Ctrl+Tab to move between adjustment points without using the mouse.
  • Shift+select multiple existing adjustment points if you want to grab more than one at a time.
  • Shift+click over the image to set your neutral point for white balance (this works outside of the curves dialog too).
  • Shift+arrow keys to move selected adjustment points by 10 rather than 1.

And then we have a few general tricks:

Danger of Death By Failing
Creative Commons License photo credit: AlmazUK

THINGS TO AVOID

  • Watch for vertical sections in your curve — that produces an extremely high contrast and you lose all midtone data in that area.
  • Watch for horizontal sections in your curve — that produces zero contrast and you lose all midtone data in that area.
  • Too many adjustment points will be difficult to manage, just use what you need.
  • Avoid inverted slopes, they invert the tones. Can you roll a ball from the upper right point of the curve to the lower left (without relying on momentum)? If not, you’ve inverted a section of your curve.
  • Don’t clip your shadows and highlights (unless that’s what you really want to do). Keep an eye on your histogram for this one.

I’m sure there are a few hundred other tips and tricks out there for using curves, but I don’t know them all and I couldn’t cover them in one article even if I did. These tips, combined with the previous articles linked at the top, should keep most of you busy for a while. And if you’re looking for more, here’s my final tip on the subject:

Experiment. Try things out, push buttons, make mistakes, and keep learning.

Nonlinear Curve Adjustments and Histograms

The last article on curves looked at linear adjustments and how those adjustments affect the image and the histogram. So now we’ll take a look at some nonlinear adjustments within the curves adjustment tool found in many photo editing software packages.

We’re basically building on our basic understanding of the histogram and our knowledge of linear curve adjustments to take the next step into nonlinear adjustments (the curvy curves).

NONLINEAR MANIPULATIONS

What I’m going to show here are some very basic curves at each extreme. The single bend and double bend curves are most commonly used during post-processing, but these are not the only options. Curves can have a large number of set points, bends, and inflections — it’s just not feasible to cover every possibility in an article like this.

SINGLE BEND CURVES

The simplest form of a nonlinear curve is accomplished by moving a mid-tone location toward the upper left or lower right corner, forming a basic arc with a single bend. Essentially, your black and white points remain fixed while your mid-tones become lighter or darker (aka: brightness). Also note that one end of your tones will take on more contrast while the other end will lose contrast due to the change in slope of the curve (remember: vertical = high contrast, horizontal = low contrast).

This can be used to brighten or darken the overall image if you want to maintain your highlights and shadows at their current values.

DOUBLE BEND CURVES

Also known as the “S-Curve”, this curve manipulation pushes one section of tones brighter and another section of tones darker (aka: contrast). Again, you can maintain your black and white points, but you also maintain some middle tone where the curve crosses the diagonal. On the note of contrast again, be aware that you will sacrifice contrast in one area to gain it in another.

This can be used to raise or lower the contrast of the overall image with a focus on the mid-tone areas. The bright/dark tone changes of the highlights/shadows are amplified by the mid-tone slope change — so it doesn’t take much to really change the contrast.

APPLYING NONLINEAR CURVES

The beauty of the curve adjustment is that you have such a wide range of possibilities — much more dynamic than a single slider adjustment. To apply curve adjustments, you simply click a location on the curve and drag it to the desired location. The curve will bend on its own based only on your set points. You can continue to add set points until you have the desired result.

Using the example image above (middle of series), here’s one possible curve that combines linear, single bend, and double bend curves. Keep in mind that I haven’t applied any basic adjustments and what you’re seeing is pure curves from an unprocessed raw file (except for the b/w conversion).

Notice that I used a double bend curve to increase contrast. Combine that with a single bend curve to increase brightness. And combine that with a linear adjustment to set my black and white points. I’ve also placed several extra points on the curve in order to bend it into the shape I wanted while maintaining a smooth transition.

As you work with curves, you’ll noticed that they sometimes have a mind of their own. Extra points will help shape the curve and provide you with the ability to make the adjustments you want. On that same note, too many set points can lead to choppy and lumpy curves. Non-smooth transitions generally begin to produce strange contrast artifacts that are easily seen in the image.

For you curves experts out there, what other tips and advice would you add to this discussion? How are you guys using curves to enhance your images?

Linear Curve Adjustments and Histograms

In the previous article on the topic of Photo Editing with Histograms, I discussed the six basic adjustments found in Adobe’s raw processing engine and how those settings affect the image and the image histogram. Then I posted a poll asking your experience level with curves, which also offered up some basic concepts and links for further reading. I also posted a few videos having to do with curves adjustments. So if you’ve been following along, you should have a decent grasp of how the tool works.

In this article, I’ll be discussing how various curve adjustments affect the image and the image histogram — but only in the realm of linear curves. So… linear… curves? Yup, you can do straight lines in the curves adjustment and they have their applications. So let’s look at a few extremes, then I’ll show you how to apply the linear adjustment to an image in need. After this, we’ll dive into the curvy stuff. And after that… I’m sure I’ll have something else to ramble on about.

LINEAR MANIPULATIONS

Let’s just start with some basic straight-line adjustments. Wait… isn’t this supposed to be about curves? Have no fear, we’ll get there — but these basic concepts are essential for the advanced concepts. Keep in mind throughout these examples that the input scale is along the bottom of the curve dialog and the output scale is along the left side of the dialog.

Each of the following examples shows the curve dialog overlaid with the base histogram, the adjusted histogram, and the base image from bottom to top. The original image is shown in example 3.

What I’m showing above is a spectrum of linear manipulations within the curves dialog. We start at full contrast and work our way to zero contrast, followed by negative contrast. Let’s go through them one by one…

The first image shows what would happen if your curve was pushed vertical. What I’m doing is taking all the pixels with tones to the left of the line and forcing them to be black. I’m also forcing all pixels with a tonal value to the right of the line and forcing them to be white. Everything between the set black and white points is scaled according to the diagonal line, thus we see a higher contrast (remember what I said about slope a few days ago?).

The second image shows a high contrast linear curve. This is very similar to the previous example, but I’m allowing midtones to remain somewhere between black and white. I’m still forcing black and white pixels, but not to the extreme as with the vertical line adjustment.

This third image shows absolutely nothing — it’s what we started with. A perfect diagonal line from the upper right to the lower left corner represents a perfectly untouched input/output relationship.

The fourth image shows the opposite of the second image. Here, I’ve moved the black and white points along the edge of the box, but in the other direction. This tells the software to convert all perfect black pixels to some level of dark gray, and all perfect white pixels to some level of light gray. Everything between black and white is scaled accordingly, thus we see a lower contrast.

The fifth image shows a perfectly horizontal line — exactly opposite from the first image of absolute contrast. What I’ve done is mapped every single input tone to output a single tone value. All blacks, grays, and whites are now a single tone value.

And our final image shows the opposite of image three. I’ve turned the curve upside down, inverting all the tones. Blacks map to whites, whites map to blacks.

APPLYING LINEAR CURVE ADJUSTMENTS

Those of you acquainted with curves and levels will say “linear curves can be accomplished with levels!” True. I’m not disputing that fact, I’m just showing how to use curves in a linear fashion. For those using Lightroom or ACR, they don’t have access to levels within the raw processor interface.

At any rate, here’s how I would apply a curve adjustment to the base image/histogram.

So what did I do here? If you look close, you’ll see that I basically did a version of #2 shown above. I set my black and white points so that my histogram spans the entire tonal range. This gives me a true black and white tonal value in the image. Of course, it’s not perfect at this point, but it’s a hell of a lot better than it was!

This is the most used real-world application of the linear curve adjustment — setting your black and white points. There are other uses depending on your artistic vision, but you’ll have to explore those yourself.

So now that we’ve covered the linear adjustments, let’s move on to the non-linear stuff! Any questions on the linear adjustments?

Photoshop Curves Video Tutorials

I’m still working on putting together my article on using curves and histograms to edit photos, so in the meantime here are some good video tutorials on the subject. These tutorials are easier to understand because they show how the curve adjustments affect the image in a more dynamic fashion.

This first tutorial is fairly comprehensive for the grayscale and combined RGB channels, covering the basics of contrast and brightness adjustments while also hitting on a lot of little tips and tricks. The creator of this video also jumps into some of the things you should not be doing with curves so that you can avoid these situations.

This second video is a little more basic than the first, but it presents some of the material in a slightly different manner. If you watched the first and you don’t have a good grasp on the curves dialog, watch this one and see if it helps.

And if you have already watched the first two videos and you still don’t have a handle on things, this last one from our friend Donnie might help. He also gets into color channel curve adjustments, so this is helpful for the more advanced users.

Tone Up Your Curves Skills

Yesterday, I posted a poll asking “How Well Do You Know Your Curves?” and I’m seeing a slightly skewed response toward the “less experienced” side of things. That’s totally cool, and I’m glad so many of you chimed in to let me know!

As I gear up to post my next article on “processing via histograms” I’m coming to the conclusion that I should put up a bit of background info on the curve adjustment tool. This tool is deserving of a book just because of the flexibility and complexity that it encompasses… but I’m not going to write a book on this stuff. Instead, I’ve put together a few thoughts and screenshots followed by links to articles far more comprehensive than my own.

So let’s get started with curve adjustments, tones, ranges, slopes, color channels, and all the other associated fun stuff.

Keep in mind that this post is somewhat of a teaser intended to get you thinking about the topic at hand. Read it through, check out the images, and follow the links at the end. I’m hoping that you’ll have a better grasp of the curves tool by the time you’re finished.

WAIT… WHAT’S A CURVE?

If you’ve worked in Photoshop, The Gimp, Lightroom, Adobe Camera Raw, and many other pieces of photo editing software, you may have already used curves or at least seen them. It’s that box with a diagonal line through it, and you can usually manipulate that straight line into a curve through various methods.

A curve adjustment is a simple input-output tool that changes the tonal value of pixels by stretching or compressing portions of the histogram. So let’s say that you want all pixels with the tonal value of 190 to change to 200 (making the light tones lighter). The curve tool does this for you, but it also moves nearby tonal values to maintain a smooth appearance in the image.

Essentially, you need to know that as you move the curve down and to the right, tones will darken from their current values. Move the curve up and to the left, tones will lighten from their current values. A curve can have many bends and inflection points, so it is possible to apply different adjustments to different sections of the histogram.

THE INPUT/OUTPUT RELATIONSHIP

As I mentioned above, you can use the curve adjustment to designate tone transformations across the entire tonal range. If you want one section of tones to become brighter, you move the curve in one direction for that local area. If you want one section of tones to become darker, you move the curve in the other direction for that local area.

A side effect of curve adjustments is the increase and decrease of contrast for different tonal ranges in the image. The slope (or how steep the curve looks from left to right) determines how much contrast adjustment will be applied to that local area. A steep slope (closer to vertical than horizontal) will give you a higher contrast. A shallow slope (closer to horizontal than vertical) will give you a lower contrast. The interesting thing about the curve adjustment is that slopes changes will alway negate each other. So if you increase the slope in the midtones (thus increasing the contrast) with a traditional s-curve, you also decrease the slope in the highlights and shadows (thus decreasing the contrast).

Simple curve adjustments are applied to a combined rgb channel. Advanced curve adjustments can be applied to individual channels in any color space such as RGB, LAB, or CMYK. This type of thing gives you ultimate control of the tones for each color representation in your image across multiple color channels, but it can be difficult to visualize and control unless you have experience with the tool.

PRACTICE, PRACTICE, PRACTICE

To best understand curves, I would suggest starting out with grayscale images rather than color. Working with a single channel will be about three times more clear than working with three channels. This scenario will allow you to explore the relationship between input and output tones without having to worry about color effects.

If you have a good handle on how the curve tool works, try messing with the color channels in the RGB space to get a feel for how they work. It’s the same concept as with grayscale, but applied to each color (red, blue, green). You can also convert your image to LAB or CMYK color space and experiment with the curve adjustment.

FURTHER READING

This topic is huge just from a technical standpoint. So rather than regurgitate a bunch of stuff that’s already been said, be sure to check out these following articles. I’ve narrowed my choices down to four articles that I feel cover the main ideas.

Tonal Range and the Curves Tool
This link from Chromasia is actually an entire series of articles on the topic of curves adjustments and everything associated with them. If you have time to read through it, I would highly suggest doing so.

Using the Photoshop Curves Tool
While not as comprehensive as the first link, this article from Cambridge in Colour covers many of the basic lessons in curves adjustments. I like this one because of how concise it is with each topic.

Photoshop Curves: Stepping Up From Levels
This article from Earthbound Light is similar to the previous article, but it hits a few different points and presents the material in a slightly different manner. Both are worth reading.

Color Correction in Photoshop with the Curves Adjustment Tool
And finally, for those of you wanting to dive into color curves, this article from PSDtuts+ gives a good introduction. It doesn’t get terribly technical, but it should give you a good idea on how the color channels are affected by curves adjustments.

As I said, this article is just a precursor to my next article on the curve adjustment and how it affects the image and its histogram from a practical standpoint. So if you’re unfamiliar with curves, read these links and practice on some of your own photos to get familiar with the tool.

More to come later this week…

Photo Editing With Histograms: 6 Basic Settings

The image histogram is often viewed as a thing of “extra information” and treated as a “good way to check for clipping”. While it’s true that the histogram provides a good check for highlight and shadow clipping, it also serves a greater purpose in post processing. Our mortal eyes are no match for the mighty histogram when it comes to tricky photos. Understanding the histogram and how your image editing software interacts with it can greatly improve your productivity and quality output.

In a recent article, I went over “How to Read Image Histograms” while providing some visual examples in the realm of brightness and contrast — two very basic concepts when it comes to photography. Now, we explore how the histogram and image are affected by other basic post-processing adjustments. For the purpose of this article, we’ll be looking at the tools available in the “Basic” panel of Adobe Lightroom and Adobe Camera Raw (other packages should have similar tools available).

These tools have unique and specific effects on the image and the image histogram. With the basic tools presented here, you should be able to manipulate your image within 90% of its final stage — further adjustments will come from more advanced tools (which we’ll look at in the next article).

In all of the examples below, I’ve added +50 to the base contrast setting so the effects of the adjustments can be visualized more clearly.

1. EXPOSURE

This adjustment acts much in the same way camera exposure does, by basically shifting the entire histogram to the left or right. This has the effect of brightening or darkening your overall image. The shadows tend to be more anchored than the highlights, and you’ll notice some distortion of the histogram as you move the adjustment to either extreme.

Notice that as you increase the exposure, the contrast tends to increase slightly due to the anchoring of the shadows. And as you lower the exposure, the contrast tends to decrease. This can be seen by the change in the width of the histogram.

For “normal” exposures, you’ll just want to make sure the histogram is somewhere between the edges. If you’re going for a low-key or high-key image, you’ll want to push the exposure accordingly. If you have a well exposed capture, you shouldn’t need to adjust this setting very much.

2. RECOVERY

This adjustment is intended to recover highlights by pulling them back down a bit. Here, the shadows are completely anchored and the increased recovery lowers the tone value of the highlights and upper midtones.

In this example series, I’ve started with an intentionally overexposed image to show the effect. In practice, I rarely need to adjust above a value of 25 or 50. Go much further than that, and you end up pulling your highlights into a gray area, making the image look flat due to lower contrast.

3. FILL LIGHT

This adjustment is the exact opposite of the recovery tool. Here, we pin down the highlights and increase the tonal value of the blacks and lower midtones.

In this example series, I’ve started with an intentionally underexposed image to show the effect. In practice, I rarely need to adjust above 25 or 50. Go much further than that, and you start pushing your blacks into a gray area and losing contrast and tonal depth.

4. BLACKS

This adjustment is sort of an anti-fill light… it brings your shadows down further into the dark region while having less effect on the highlights. This is good to use when you have less than perfect blacks and you need to tug that histogram just a little to the left.

In this example series, I’ve started with an image of slightly higher brightness to better show the effects of this adjustment.

5. BRIGHTNESS

We went over the brightness adjustment in the last article, but I’ll add a few notes here. You’ll notice that it acts very much like the exposure adjustment, pushing the image brighter or darker (and moving the histogram to the right or left). But it does this in a slightly different manner. The exposure control is more directed toward the extremes of the histogram, while the brightness control is more directed toward the center of the histogram (midtones). It still moves your highlights and shadows, but it moves more of your midtones than exposure does.

In this example series, I’ve started with the default image of +50 on the contrast and no further adjustments.

6. CONTRAST

We also went over contrast in the previous article, noting that the wider histogram equates to more contrast. This is a handy adjustment tool to use when your histogram doesn’t quite reach the edges at the blacks and whites, or if your image looks flat due to a heavy midtone concentration.

And again, you can see that the brightness and contrast adjustments are tied together and not completely independent.

HOW IS THIS USEFUL?

Understanding your histogram allows you to process the photo on a technical front rather than on pure aesthetics. Understanding how these basic adjustments affect the image and the histogram will allow you to manipulate it with more confidence.

But don’t get too caught up in watching your histogram — in the end, the only thing that matters is a photo that appeals to your eyes.