Today, I'd like to start talking about reference. How I take it and how I use it. Though I can't tell you how to use photographic reference in your own work, it's entirely possible that you'll pick something up from how I do things, all the same. Or, you may find humor at how naive and stupid I am. Either way, I'll begin by talking about equipment.
First, the camera.
In the dark ages, before the enlightened time of digital photography, there was this stuff called film. While it was pretty awesome, it had a very limiting factor in that there were only so many shots per role and you had to be sure you got what you needed before taking your photographs in for developing. Oh yeah — developing. You actually had to go some place to have your pictures developed which took at least an hour of your life away. No instant gratification with film, no sir! If by chance you failed to get exactly what you wanted with the film, you had to rinse and repeat as necessary. It wasn't cheap and was very irritating at times. All the same, I liked having those pictures in hand, and kind of miss using my trusty Pentax K1000.
If that option didn't suit you, the next best thing was a Polaroid camera. I had one of these, too. As there was no negative, each photograph was it's own little original. They were terrible looking, but if you needed your reference quick and dirty, this was the way to go. Of course, this cost a fair bit of money, too. Each shot cost you at least a dollar and you could blow through shots pretty quickly. The upside, however, was that you didn't have to go somewhere to have the images developed. It only took a few minutes for each shot to appear out of the gloom.
Then there's the issue of storing everything which I won't even get into. Suffice it to say that I have boxes of reference that I hope to some day digitize and throw out. Won't that be fun?
In short, digital photography might be the best thing that's ever happened to photographic reference. You can see the image immediately after pushing the button, you are limited only by how much storage space you have, and there are no developing costs. If, like many out there, you work off of a computer screen rather than printing your photos out, you save even more. Kind of crazy, really.
Oh yeah...so my cameras. I have a Nikon Coolpix point and shoot camera that I sometimes use. Alternately, I will use my Nikon D200 SLR. Why I use one over the other varies. If I need more control over the settings and more detail, I grab the D200. If it's quick and dirty, the Coolpix will suffice. Otherwise, it might be because one is charged and the other is not. Real professional, I know.
Anyway, if you're just starting out and don't have a lot of money, look online, do a little research, read some reviews, and find a cheap, reliable point and shoot for the job. The point and shoots being made today have superior resolution to my SLR and take some pretty amazing pictures. Eventually, though, you might want to consider saving up for an SLR or at least a camera that can give you raw files.
What's so important about raw files? Well, raw files are about the closest thing you'll ever get to having a negative in digital photography. Just as you could in film photography, you can pull a lot of data from and manipulate the raw image's colors and values before having it compressed into a jpeg or tiff or some other format. While you can certainly manipulate compressed images quite effectively in Photoshop, manipulating the raw files can give you much better results.
Now, note that I said that you should "consider" a camera that can give you raw files. This is because not everyone uses reference the same way. Some people paint exactly what they have in their reference photos. Others do not. Raw files can help you get more out of your photographs if you fall into that first category. I, myself, fall more into the latter category. While I shoot reference to get certain things right, repainting what I already have a photo of really doesn't interest me. Even so, I still will manipulate the raw files from time to time. It all depends on the demands of the project.
No matter what kind of camera you have or end up with, it is worthless if you don't know how to use it. Even "simple" point and shoot cameras have hundreds of settings nowadays and can be tweaked ad nauseam. Try everything. You don't have to print it out, just see what each option does. The more you understand what your camera is capable of, the better your results will be.
So, there you go. Not everything you need to know, but all I'm qualified to give you.