I recently had a student at BetterPhoto.com ask some questions that really asked more than they seemed on the surface. They bring up some important ways of looking at photography and image processing today, so I decided to include them and my answers here. There are no simple yes or no answers to any of these questions.
"When I adjust the basic controls in Lightroom and it affects the entire picture, should I be concerned that if I go into a local control, that the combined effect will be too much?"
Very often we will be using the same control for overall adjustments as well as for local adjustments. Sometimes we only want a small amount of adjustment overall but need to intensify that adjustment in a specific place so we use the local adjustment for that. On the other hand, sometimes an overall adjustment does nice things for the whole picture, but it's too much for specific parts of the image and so we need to make the local adjustment reduce the overall adjustment there.
This is traditional darkroom work. Anything that you do to a picture can be too much or too little. It all depends on what the picture needs. That said, one of the nice things about Lightroom is that you can experiment and try all sorts of things without any effect on the original image. Lightroom applies nothing until the image is exported out of Lightroom. You can change and re-change adjustments to see what they look like as much as you want and nothing is harmed.
One thing that can be very helpful is to use a Virtual Copy. If you right-click on an image, you will see the Create Virtual Image command about midway in the menu that appears. This creates a new reference to your picture, not a duplicate of the original file. You can now do adjustments to this virtual copy that are different than your adjustments that you did to the original copy. You can do as many Virtual Copies as you want and they are all there for you to make comparisons to see what you like best and to see if you have done some things that have gone too far.
What is important is what happens to your photograph not how you use specific controls. That is a mindset, not simply a matter of working with Lightroom. This is actually not just about Lightroom.
This goes back to classic darkroom work. I think you might find some of Ansel Adams books about photography very useful to help you as you think about this. His book, The Print, for example is still in print and has some excellent ideas about how we approach an image to process it and make it look its best. It is about getting the most out of your photograph, not about how much or how little you use any specific control.
As you work more and more with Lightroom, you will find that you will actually change how you make your adjustment. When you first start working with Lightroom, there is a tendency to over adjust an image because it just looks so cool. After a while, that over adjustment will not look right and you will start to make some changes. You need to look at your picture, at any individual picture, as a unique image that needs your attention, not some arbitrary thoughts about what can or cannot be done to it, and you need to pay attention to what it has to tell you about what it needs.
"For example, if I adjust the clarity globally and then again locally, is it a combined effect and will this be a problem with print quality?"
Yes, this would be a combined effect, but it's not really about print quality as much as it is about what the picture looks like. Clarity is not about sharpening. While it looks like sharpening, it's not. It's about how Lightroom is affecting the details of midtone contrast. Because of that, the problem with Clarity is often that it will make your picture look too harsh if used too much. That's not a quality issue, but an aesthetic issue.
"Also, how far can I go without considering it to be cheating?"
This question sounds very much like you have been listening too much to baby boomers who are still a little afraid of the computer and the digital world. I am of that generation and I know how much this group has really fought dealing with computers and their fear of the computer often is reflected in things such as, "That's cheating!"
The crazy thing about this is that they think nothing about other things that have an equal effect on images and they don't consider those things cheating. If a person has enough money to travel to Tahiti and take underwater pictures there, is that cheating compared to the person who can only afford to photograph underwater in a local lake when both are entering the same contest? If a person has enough money to afford a $10,000 600mm lens and can go to Africa and enter pictures in the contest from that, is that cheating compared to the photographer who struggles to afford a $1000 lens and can only visit a local nature center? Personally, I think those things give people a greater "unfair" advantage in a competition than anything somebody would do in Lightroom as far as contests go.
Adjusting an image to get the most out of it is not the same as distorting or lying with a photograph about what you are seeing. It is important to keep in mind that we see the world very differently than the camera does. The camera sees "a" reality, but it is not "the" reality. We see subjects and we can see a huge range of tonalities from dark to light as well as see pure color from dark areas to bright areas. The camera can't do any of that. The camera only sees light and dark and is limited as to how big a range of tonality it can deal with.
This means that very often we have to make adjustments in Lightroom in order to bring the truth out of the scene. Andreas Feininger was a LIFE magazine photographer who also wrote a lot of books about photography in the 60s and 70s, way before computers were important to our work. He said that the uncontrolled, unadjusted image is a lie because it does not reflect the way that we see the world. It is only through adjusting and controlling the image that we actually bring the truth out of this. We can actually adjust something and distort and lie about the world, as well.
A lot of folks who use the word "cheating" when referring to image processing have a misunderstanding of what the camera actually can and cannot do. We cannot put the world inside a camera. The only thing we can do is interpret that world. The world literally does not fit! I have had people tell me that they don't worry about image processing because "nature is perfect." Well, nature may or may not be perfect, but cameras and sensors certainly aren't.
Pointing a camera at a scene does not guarantee an accurate or truthful rendition of that scene, no matter how expensive the camera is. Yet there are people that seem to think it does. Even a RAW photo is an interpretation based on the limitations of the sensor as well as design parameters of the camera engineers and specifications desired by marketing. Yes, marketing.
So I believe our goal in working on an image in Lightroom is to bring out the best in that photograph so as to express something about how we felt about and understood that subject and scene. How you do that will be influenced by the ultimate use of a photograph, i.e., a picture done for a newspaper is going to be different than one that is designed for a fine art gallery.
Still, we have to look at the picture and ask ourselves what does it really need? What is it telling us that is important to it as a photograph – and I know that sounds a little odd, but that's really what you're doing is not trying to impose something on a picture, but trying to find out what is inherent qualities and truthfulness are and using your processing to bring that out.
Given your thoughtful questions, I would highly recommend that you read a little bit of Ansel Adams, especially his book The Print, and some of Andreas Feininger. While you can get Adams books almost anywhere, Feininger's books are long out of print. You can actually get them quite cheaply from places like AbeBooks.com where it will cost you more for postage then for the book.
"Lightroom makes pictures look so much better, but if I am entering a contest,is it fair to use it?"
Contests will really vary as to what is seen as appropriate for the contest and you have to pay attention to that. However, I find that very often it is the smaller camera club contests that are controlled by baby boomers that are more likely to have rather arbitrary rules as to what is fair or not. You're not going to change that, but you can be aware of those restrictions – see them simply as rules that are appropriate for that particular contest.
There are many times that pictures should look better after it's been in Lightroom then when it came from the camera. An image from the camera simply doesn't reflect what the world looks like to our eyes at times. I have judged contests literally around the world and the biggest problem I see is not from adjustments being "unfair" but from adjustments being garish and unattractive because the photographs are over adjusted. This is something that is consistently a problem for judges. In almost all contests, judges will reject those photos because the pictures then become more about the processing than about the photograph and what the photographer is trying to say with that image.
That said, there are still going to be folks running contests that will consider any Lightroom work "unfair", etc. The only thing that's going to change that is time.
To give you an idea of how crazy this can be, I had a friend that was doing some work for a publication a few years ago and the art director (an older baby boomer type) questioned the darkening of the sky of one of his pictures. This was simply traditional darkroom type of darkening and could've been done with a graduated neutral density filter. However, my friend had done this in the computer and the art director said that that was wrong and they couldn't accept the picture. My friend asked what the difference was between a picture darkened that way in the darkroom or using a graduated filter and the director said that those things were okay, but adjusting in the computer was not. That's just odd and luckily most people are not that extreme or so fearful of the computer.
All of the photos here have had some adjustment in Lightroom, all basically "darkroom work" to help the image work at its best. The first and second photos are from the Santa Monica Mountains (California), the third is by Morro Bay (California) and the last is from near Boulder (Colorado).
My Lightroom course at BetterPhoto.com is all about "darkroom work", and like all BetterPhoto.com courses, includes assignments and critiques. I also have videos available on organizing images with Lightroom Library and success with image processing in Lightroom Develop at Skillfeed.com.