Digital Darkroom Tips

[Mark]

Barrie made a request for Photoshop How-To tips. This isn't exactly that, but it's something along those lines that I think will be useful.

I'm going to make this a collection of tips on how I work through the "darkroom" process of a typical image. It won't show you how to remove your ex-spouse from a picture. It won't show you how to shrink your waist, or change the color of your eyes. It's just a set of tips on how I typically develop an image from the camera.

Here is the image that I started with:
http://barbieri.smugmug.com/photos/145542465-M.jpg

[Mark]

The first thing that I do is set my white balance. Light comes in all different colors. The light from a regular lightbulb is sort of orange compared to the sun. The light in the shade is sort of blue, because so much of it comes from the blue sky. The source of the light and the color of the things that light bounces off of all change the way the light looks.

I usually just shoot in Auto White Balance mode and it's good enough most of the time. If you want the most accurate white balance, you should use a custom white balance setting on your camera based on a shot of an Expodisc or a grey card. The next best thing is to find something that you are sure is neutral colored (white, grey, or black with no color at all) and use it as a reference point. Most software packages have a way for you to pick a neutral spot and it will adjust the white balance for you.

If you didn't use a custom white balance setting and you don't have a neutral colored spot (like a white T-shirt or sock), you've got to guess. In this case, because I was shooting under normal sunlight, I'm going to switch from Auto white balance to "Daylight".

http://barbieri.smugmug.com/photos/145542462-M.jpg

One word of caution about playing with white balance settings. When you are working with a group of pictures shot with the same lighting, use the same settings for all of your pictures. If you tweak it on a picture by picture basis, people will notice that the colors shift between pictures. It's a lot worse to do that than it is to have your colors consistently wrong.

[Mark]

The next step that I like to take is to crop the picture. I often decide to cut off parts that don't add to the picture. Doing it early in the process allows you to focus on only the part that you are going to keep. If you crop towards the end, you might adjust your settings based on stuff that you later throw away.

In this case, I made a severe crop. My original concept was a picture of a flower that had a spider on it. I decided that looked boring and switched to a picture of a spider on part of a flower. I usually don't crop this much, but sometimes it makes for a more interesting picture.

There are downsides to making large crops. First, you lose a lot of resolution. Before I cropped, my picture was 3504 x 2236 pixels. After I cropped, it was only 1203 x 802. I went from an 8 megapixel image to a 1 megapixel image. That will really hurt if I decide to make a large print of this. For a 4x6 or displaying on a computer, it isn't that big of a loss.

One downside to making large crops is that you are magnifying the remaining part of the picture. Small errors like being slightly out of focus or having your subject moving during the photo might not be visible in the original shot, but when you magnify those errors, they may ruin the picture.

http://barbieri.smugmug.com/photos/145544404-M-0.jpg

[Mark]

My next step is to adjust my exposure. My goal is to not have any under or exposure but to maximize the available dynamic range of the image. To do this, you need to understand how to read a histogram.

http://barbieri.smugmug.com/photos/145545274-O.jpg

The histogram is a graph of brightness levels of pixels in your picture. The left side of the graph represents the darkest pixels and the right side represents the lightest pixels. If your histogram is mostly on the left side, that shows that you have a dark picture. If it is mostly on the right side, you have a bright picture.

There are no "good" histogram shapes. It all depends on what you are shooting. If you shoot a pale woman in a white wedding dress standing in the snow, you'll end up with a histogram with lots of stuff on the right side. If you shoot a dark skinned man in a dark tux standing in front of a dark night sky, you'll have lots of stuff on the left side. Put the pale woman and the dark skinned man together in a photo and you'll have a bunch of pixels on the left (representing the dark stuff) and a bunch on the right (representing the light stuff).

There are "bad" histograms. The worst histogram is one where there is a tall line right on the very rightmost edge. The rightmost edge are pixels that are as bright as they can possibly be. The "tallness" of the line indicates that there are a lot of those pixels. That probably means that you overexposed part of your picture and you have a big white area with no detail in it.

The next worst histogram is where you have the opposite problem - a tall line on the very leftmost edge. This represents a part of the picture where you have underexposed and you have a dark area that has no detail.

My histogram is comfortably in between the edges, so my exposure lose any information. What I want to do now is to stretch the light levels in the picture so that my photo ranges from totally black to totally white. That works for many, but not all subjects.

To do that, I'm going to play with a couple of adjustments. First, I'll increase the exposure until the right part of my histogram hits the right edge. Then I'll increase the black level until the left part of my histogram hits the left edge.

With Photoshop and Lightroom, you can hold down the Alt key while you make these adjustments. They will make your picture disappear and will only show you the parts of your picture that are too bright or too dark.

Now my histogram looks like this:
http://barbieri.smugmug.com/photos/145547765-L.jpg

My picture looks like this:
http://barbieri.smugmug.com/photos/145547762-M.jpg

Now you're probably thinking that I screwed up because my picture looks too bright. I'll fix that soon.

[Mark]

My next step is to use Curves to make more subtle adjustments to my exposure. Curves allows you increase or decrease the brightness of different brightness ranges in the picture. For example, you can use it to lighten up the shadows a bit while simultaneously dimming the highlights.

Here is the tone curve before I started any adjustments:
http://barbieri.smugmug.com/photos/145549213-L.jpg

A straight line from the lower left to the top right of the curve control represents the picture as it is before you start adjusting. Like the historgram control, the left side represents the dark parts of the picture and the right side represents the light parts of the picture. If I drag part of the curve line up, it makes that part of the picture brighter. If I drag it down, it makes that part of the picture darker.

In my case, I want to dim the highlights a little so that the details in the flower show up. I do this by dragging the right (bright) part down (darker) just a little bit.

In this case, I'm going to dim the highlights a little. The flower is very bright and after the exposure adjustment I can no longer see the details.

Here is the tone curve after I made my adjustments:
http://barbieri.smugmug.com/photos/145549214-L.jpg

Here is my picture after the curves adjustment:
http://barbieri.smugmug.com/photos/145549216-M.jpg

[Mark]

My next step is to adjust the overall color saturation of the photo. My camera is set up to shoot with fairly muted colors. That means the pictures look less stunning right out of the camera, but it gives you more control over how you want to adjust the saturation.

In the case of this photo, I'm going to make a small increase in the saturation. In Lightroom, I'm using the new Vibrance control. It works almost the same as saturation.

My adjustment in this case was very subtle. Heck, it might not even have been worth bothering with. It brings out the creamy color of the flower just a bit.

http://barbieri.smugmug.com/photos/145550678-M.jpg

[Mark]

My next step is to make fine adjustments to invidual colors in the picture.

In this photo, I'd like to adjust the green of the spider a little so that it stands out better. I'm going to increase it's saturation while also decreasing it's brightness. Both settings have the effect of increasing the visual contrast between the spider and the background.

http://barbieri.smugmug.com/photos/145552352-M.jpg

[MissBianca]

I'm hanging on your every word here :yes:

[Mark]

The next step is to get rid of "noise" or unwanted colored dots in the picture. The higher your ISO, the more likely you'll have unwanted noise in a picture. I use software called Neat Image for noise reduction, but there are many other really good packages that do the same thing.

One thing to be aware of with noise reduciton is that it is also detail reduction. It's impossible to tell for sure what is noise and what is fine detail. The more aggressive you are about getting rid of noise, the more you will lose detail.

In this case, I've got it pretty easy. I have a very clear and easily selectable part of the image that is out-of-focus. Because it is out-of-focus, it shouldn't have any detail. I'm going to select that area and then apply some very aggressive noise reduction to it. You should be able to see that the background looks a bit smoother now.

http://barbieri.smugmug.com/photos/145554070-M.jpg

[Mark]

My next step is to resize the picture for my intended display device. In this case, I'm going to show it to you on my Smugmug account at it's "Large" resolution. That happens to be 800 pixels wide, so I'm going to resize my image to 800 pixels wide by 533 pixels tall.

I could have just uploaded it in whatever size I wanted and then let Smugmug resize it (which I usually do), but if I want it to look its best, I'll do all of the work myself rather than trust the website to do a good job.

It just occurred to me that this is probably confusing because I just shrunk the picture (from 1203 x 802 to 800 x 533) but you see it as larger. For the prior pictures, I was downsizing them before uploading them so that they wouldn't take so long to download. I was still working with the picture at 1203 x 802. Sorry for the confusion.

http://barbieri.smugmug.com/photos/145555766-L.jpg

[Mark]

The last editing step that I do is sharpening. In the reverse of the noise reduction part, I am only sharpening my subject. Sharpening out-of-focus areas is a bad idea because it creates a sense of detail that you generally don't want in your out-of-focus areas.

I'm usually too lazy to do anything special and just sharpen the whole darn picture anyway. When it's a really high ISO picture there is often too much noise and sharpening makes the noise even worse. Even when noise isn't an issue, if I'm trying to be good, I'll create a layer with just my subject on it and then sharpen it. That helps draw your eye even more to the subject.

In this case, I just sharpened the part that wasn't the background area. I used Photoshop's Unsharp Mask. I usually just play around with the settings until I get a look that I want. If you do that, make sure that you are looking at the picture fully zoomed in. Also, I find it useful to oversharpen before printing because printers really seem to soften up an image.


http://barbieri.smugmug.com/photos/145558400-L.jpg

[Mark]

Not a particularly stunning image and not any amazing techniques. It's just my usual routine for taking a picture from the camera to posting it on the web.

I use Adobe Lightroom for most of my work because I find it more efficient than Photoshop. I still fall back on Photoshop for some tasks like noise reduction and sharpening. You can do just about everything I talked about with just about any good photo editing tool (Paint Shop Pro, Gimp, etc.).

I hope that was helpful. Maybe someone else will start a thread on cool tricks like making frames, cutting out ex-spouses, etc.

[MissBianca]

Wow! What an awesome difference from your starting point. Could you say more about how to use the Unsharp mask? I've not figured that one out.

[Ursulinda]

WOW! I'm speechless with awe. . . that petal looks so REAL and who knew that spiders have hairy legs?

[Mark]

who knew that spiders have hairy legs?
That's how you know it's a European spider. American spiders shave their legs.

[MissBianca]

That's how you know it's a European spider. American spiders shave their legs.

:lmbo:

Linda, have you ever seen a tarantula? They're REALLY European, apparently.