First off, why process digital photos? Long story. I figure it's important to understand why one bothers doing so. If you pick up a magazine with photos, you can rest assured post-processing was done to the images in some form or another. It's not evil, though some sure want to believe it is. Digital post-processing is a bit like developing was to film in the past. Not all film developing was equal. Some knew all sorts of ways to help their images. Same can be said now with digital. All digital cameras take the photo and have raw data stored, which then gets some sort of manipulation done to it via software settings within the camera, like contrast, sharpness, saturation, etc. Some allow you to change those settings first, though it's usually not that fine tuneable. So it gets the data, then it "develops" the file you see as a picture. Most of the time it saves these as JPG files, maybe others like TIFF files. JPG is a compressed format. So if it saves it as a JPG, it not only decided all the developing settings(software in the camera), but it also then compresses that available data into a smaller file. For a lot of scenes and images, this will work fine. If one wants the most from the camera and what is available out there, they'll chose a format called RAW. RAW is like the others when the images is taken, but the camera saves that RAW data without applying any of the camera's available settings(contrast, sharpness, saturation, white balance, etc). So the "developing" step is left out for the moment. You get what is equivalent to a film negative. You then save that to your computer, and open it with RAW conversion software. In this software you can now apply the saturation, the contrast, sharpness, white balance, and many other things(depending on the program you buy). Other things may include noise reduction, lens distortion corrections, purple fringing fixes, among others. Then, rather than having that compressed JPG file to work further with in regular photoshop, you can save those applied settings to the image you've created, as a TIFF file. A TIFF file is not compressed. One thing you don't want to do in photoshop, or any other photo editing software, is to resave JPG files. It's a real bad idea to keep compressing a compressed file. This is not an issue with TIFF, especially if you saved as a 16 bit TIFF file instead of an 8 bit one. More on that later. But anyway, this is a really simple concept. If you want the most control and the most you can get from an image, you simply chose RAW. If you don't need that and are happy with JPG, fire away. I'd much rather have that RAW file as my original though, compared to having a compressed file format like JPG. Also, before doing much of this, you'll want to calibrate your monitor. This doesn't have to be confusing either. The best calibrated monitor will show a greyscale from white to black with white whites, black blacks, and still be able to see the steps between the shades in the greyscale(the more shades in the grayscale and the more steps you can see, the better). My monitor is calibrated and I can see a difference between all those shades. The first couple black ones are pretty tough, but I can see the change between the first and second. This is set using the brightness control on your monitor, along with the contrast control. You don't just want to see the steps, you also want black black and white white. If the contrast is too high, you often have your black black and white white, but probably won't be able to see the steps between all the shades. Some monitors may not be able to show this. Generally CRT monitors are better for photo work than LCD ones. LCD ones can be pretty contrasty, and they also tend to change lightness depending on the angle you are looking at it. Getting this right will try to put everyone on the same page when looking at images online. If yours is way off, you'll be seeing images made on a calibrated monitor a bit off. I never did this early on and I had some funky images online. If my monitor was too dark when I processed the images, then everyone else would be seeing too light images. If I had it too bright, then others would see my images as too dark. If I remember right, the goal with the black and white shades was to have it set at the lowest amount to where you can just start to see the next shade. So with the black side you'd want to just barely be able to see that second shade. Same with the white, you want the last block to be as white as possible, but you also want to just barely be able to see that shade right before it. You also don't want color casts in your grayscale. So, a monitor needs the lightness and contrast set right, as well as the color balance. For the color balance part I'd buy a Spyder. It sticks on your monitor, then the software that comes with it runs color shades. It reads those and then at the end sets your monitors color settings into a profile. Then when you turn your computer on, that profile is loaded into your graphics card to change how things look on your monitor. With mine I still had to do this grayscale lightness/contrast setting myself, so if color doesn't matter much and you just want lightness/contrast right, I'd just use one of the many online grayscale calibration images. If you really want a great online site to see how well your monitor is calibrated, and to calibrate it(as well as maybe see how poor of a monitor you may have).... go to this link: http://www.drycreekphoto.com/Learn/Calibration/monitor_black.htm I can see the 3rd black block on that page, but boy on the next page on there, things don't seem so hot.

Histograms. I guess this is a good next step here. Learn what a histogram is and how it displays the image information. It'll help you understand the image itself. The above black peaks thing is a histogram for the image above it. The far left side of the histogram represents complete black and is given a number of 0. The right side represents complete white and is given a number of 255. You can't have anything darker than complete black or brighter than complete white. So in an image you have lightness levels from that black/0 to that white/255. All that black stuff on there making up those peaks from left to right, those are the pixels making up your image. The taller they are in a given location, that shows you have more pixels fiting that lightness level. So if you have pixels stacked up against the left side on there, those are all black in your image. If you have some stacked on the right side, those are all white. As you move to the right, away from the left side, they are given lighter shades. So you can see that big stack on the left side of this histogram. In the image above you can see just how much area is in those dark shadows. A good chunk of that picture is near black, so that's why that peak is there on the left side of the histogram. What are the other two areas taking up a lot of the picture? The sky and the snow. Obviously those two lightness levels are those two middle peaks seen on the histogram. That tiny peak on the right side of the histogram, the highlight/white side, would be the sun where it's blown out to complete white. As another way to think of this, the text you are reading has a lightness level of 127. The tricky part with the photo comes when you realize it's made up of red, green and blue combinations(RGB). With red you have 0-255 levels of lightness, from dark red to bright red. Same with the blue and green channels. To get a grey shade they all simply have to be equal. Red = 0, Green = 0, and Blue = 0....and you are left with black. Red = 127, Green = 127, and Blue = 127 and you get this shade of grey that I'm typing with. Red = 255, Green = 255, and Blue = 255 and you get white. Red = 255, Green = 0, and Blue = 0 and you get bright red. Red = 255, Green = 255, and Blue = 0 and you get bright yellow. Anyway, that's how one gets colors with RGB. Each color gets its shade via the three color channels of red, green and blue, and the amounts or lack of from each of those.

Now note how the foreground in that image is so black. Was it that way in person? Of course not. The snow lightness was close to that, but the shadow stuff was not completely black like that. This is a problem with cameras, not just digital, but even film. Camera's cannot capture the dynamic range of light that our eyes can. They can get a lot of them, but many scenes the dynamic range is too great. Any sunset scene is like that, or a scene in a building which has windows on a sunny day. One can use a split neutral density filter to help with this, on a scene like above. All that filter is is a piece of glass which is tinted/shaded darker on one side. So the tinted/shaded part would be for the sky, to hold it back from being so bright, allowing the exposure to be greater to get the shadows right. That would work well enough for anything with a straight horizon like that. It however won't work well with other scenes, especially a storm with strong under lighting. Those scenes you have the dim foreground and dim storm, with the very bright sky...leading to a dynamic range too large for the camera.

Now in post-processing it is possible to open up areas made too dark, only to a certain degree though. I opened up(lightened) that area of the trees, and only that area. See where that chunk of the histogram moved? It moved right, since it isn't so close to black now. Now here's an important thing to understand about this. If you shoot anything and there are pixels ramped up against the left or right side of the histogram, it is called clipping(as in all the way on the side, not just near the edge but the actual edge of the histogram). You've clipped off info, like tree detail in a shadow area. In the first example and histo on here you can see much of it was near the left side, but not all of it all the way against it. So there was some data in there, even if it was very near pure black. That is the data that could still be opened up some. But I do think a section was completely clipped black, and that is the treeline area just below the horizon. See how in this opened up image above, there is tree data in there, but there doesn't appear to be any in that area right below the horizon. If I clipped that area to pure black in the original, there's no data/info there to recover. If it was close, but just a smidge lighter shade from black, there'd be data in there to see. As it is, there doesn't look to be. All you can do with solid black is lighten it to an evenly equal shade of grey. You can see that is what happened here when I tried to open it. That area right below the horizon is lighter than before, but there's really no detail in there, just the same shade throughout. So, it's possible I can brighten that all the way to almost pure white, and you'd still not see any tree separation/detail/info there...because it was clipped to start with. So it's important to not clip things. Once you do, you can't get that info back. It's also a bad sign to see that tooth comb appearance to the histogram. That can be seen to the area I lightened on the left side. That's surely attributed to opening the shadows of the 8 bit JPG file. That's another thing. Most cameras shoot and capture the raw data at 12 or 14 bits. If you chose the JPG file, the camera applies the in-camera settings for saturation, contrast, sharpening, etc and saves it as a compressed 8 bit JPG file. An 8 bit JPG has 256 lightness levels to work with for each pixel. This is that 0-255 grey scale like has been discussed about the histogram. Black to white with 256 levels of lightness(255 + you would count 0/black too, so you get 256). 12 bit gives you 4,096 lightness levels to work with, and 14 bit gives you 16,384 lightness levels. So if you save it as a JPG, wave bye bye to all that available data. In most RAW converters you can convert that data to an 8 bit TIFF or a 16 bit TIFF. A 16 bit file gives you 65,536 lightness levels to work with. Even the 256 levels, 8 bit TIFF option will be better than JPG. But if you shoot in RAW you can do one or the other(convert to 8 or 16 bit TIFF) anytime you like. 256 levels may not seem like much after hearing about 65,536, but it's still a good number of levels from black to white. The above grayscale goes from black to white, obviously. You can count the shades yourself if you want, but there are 33 of them, or 33 levels. This is just an example, a person can make a grayscale however they wish. What I'm trying to show is just how much 256 levels would be. To make a grayscale from black to white like this, with 256 levels, you'd have to have 7 more steps between each of these shades. It gets pretty hard to see a difference between shades at that amount. So for most all applications, 8 bits(or 256 levels) would be plenty. I'm not even sure if printers print anything much greater than that. So why bother with 16 bit TIFF files and 65,536 available levels? Having that kind of data can come in handy when processing images. I've had some sharp contrast images, from my old piece of crap kit lens, that when processed via 8 bit, would show banding in that area of contrast. The kind of contrast I'm talking about is like a brightly back-lit storm, where the image goes from dark on the storm, to bright on the sunlight shining around. I would apply very little contrast to the file and get this funky alternating banding through that zone of the image. Instead of a nice gradient from dark to light, all I would get is that striped garbage. This went completely away once I started processing in 16 bit. I've never gone back. So, I make sure to work with RAW and get that 16 bit TIFF file in conversion. If you are shooting a scene full of detail like a street photo or something, this may not be important. Detail loves to hide any possible flaws or artifacts. Sky and clouds, well they don't. The other thing about clouds, or storms, is that the dynamic range is often huge. In those cases it really is best to have the most available data one can.