There is a video by adobe that mentions contrast change via curves. Mike's adding more grey isn't a good way of appreciating that. Say a curve has one point on it and you add another at a darker tone level and drag it down. It will darken that tone and all tones above it up to the next point where ever it is. What has happened is that the brightness range between the 2 points has been expanded. This is an increase in contrast. Another way of looking at it is that the slope between the 2 points is steeper = a contrast increase. If you push the point up the opposite happens, the slope is less steep, the brightness range between the 2 points has decreased so contrast has been reduced.
The video. As usual it doesn't cover different situations and you are probably aware of the options but just in case. The CinC tutorial is better.
https://helpx.adobe.com/creative-clo...h=fundamentals
As always it's just an S curve. Usually based on 3 points that quarter the 45 degree line things start with. Often another point splitting the dark region into 2 is useful. The 3 points can be moved around if needed.
As the swan is a good simple example the 1st thing to do is adjust the exposure so that the darker tones in this case black are correct while the curve is still a corner to corner straight line. You'll probably find that when you look at the histogram there will be space at the dark end. Ok for now. Then look at the highlight end. It might stop short, the image might look great apart from titivating. No need to do anything else here. Ideally if the image needs local contrast, clarity or what ever titivating adjustments some space is needed at both ends of the histogram anyway.
Life often isn't this simple so the first thing to do is to use highlight recovery sliders to see what they can do. Again space is likely to be needed at the end of the histogram for titivation. Rendering such as film like and other similar bits and pieces will make a difference as well if they are there. Then there is often a shadow/;low light recovery slider. That along with exposure changes can be used to bring more high lights in,
Many shots need no more than this and the curve is still a straight line, It's a good idea to use clipping indicators as this work is being done especially if the result turns out perfect so final adjustments need to be made. Generally black tones need elevating by a few bits due to the way PC screens work otherwise they will just give a flat black. All depends on the shot. I suspect Adobe show all channels clipping from some one else's work a while ago. Some times one or two channels clipping has no visual effect on colour at other times it does. Depends on the degree. When that happens the tone levels have to raised some how until colouring is restored. Lightroom had been used to process the shot. I looked at it with a package that allows any channel clipping or all channels clipping to be seen so could see the problem. The problem with adjusting for any channel clipping is that it can make images flatter than they need be. On this shot allowing some channels to clip left grass looking like mush.
Still no good - this is the time to play with curves bearing in mind the contrast effects. A typical S curve will always have a point at the centre and be an even S shape too start off with. The idea at both ends is to avoid clipping. At the dark end that means not allowing black to reach zero. Your viewing sRGB but the software is working at a greater colour depth so providing that it retains the numbers they can always be brightened up latter so that the look right in sRGB. A fill light might do that or a shadow recovery slider or brushing a higher contrast dark end curve over it. In some case an inverted S curve can be used. This reduces mid tone contrast but some of the titivating adjustments mainly work in this area.
Moving the exposure to take out a background is just making life more difficult. If it works then it should be possible to produce a mask of sorts by duplication the results from above in PS, Not that it will always work so some hand painting is likely to be needed. Masks can be inverted so it's a case of isolating the easier one.
To be honest though Christina with respect you would probably progress a lot quicker if you just used adobe raw for a while and learned to make full use of all of the bits and pieces it can offer and save layers for when they are needed. Adobe have done a few dumb video's about some of what it can do. There are plenty of tutorials on specifics about on the web including it's curve but none of those are likely to explain the effects, just show what the controls do. One video explains how to make an adobe raw processed image into some sort of smart object that links directly to PS and saves settings etc as well so that it's possible to go back and change them. Not that this is a good idea because the idea coming out of raw is to get a good image that contains as much information on tone levels as it can and then doing further processing. Sometimes there is just too much tone range to handle sensibly. That means sacrificing high or low tone levels completely or over compressing them with S curves or what I might do 2 exposures from raw blended with Enfuse and maybe needing a little more work on the result. This saves a lot of local work.
Reflections - easy with the right tools. Select the object, cut it, flip it vertically some how and paste it onto a transparent layer in the right place and mode so that ripples in the water are still visible. This may mean work on both layers locally to make the ripples look correct. Mentioned because I some time see shots where the ripples stop where the reflection is. Or just treat what you have locally, often easier.
All this may be a bit jumbled. I've been a bit occupied elsewhere today so have added to it several times over the day.
Me well if the camera jpg does a decent job of the tone curve I don't bother with raw and just do the titivations on it. Adobe raw will do that too. I only use layers when I need to or when basically trying methods out. My way of putting it is that I am in no way a raw snob. I have even used layer techniques on jpg's. I've never had the slightest problem with posterisation only colour shifts if things get pushed to far.I have had posterisation problems at times adjusting other peoples shots. In my view that means that the processing that produced them is NVG. Probably by doing things in the wrong order / using the wrong method to get there. Curiously my cameras don't do that. I don't seem to have any problems doing further work on my own jpgs' either. Handy as after I have finished a shot I need to get away from it for a while and then take another look. I also do a series of adjustment fairly quickly look a the results and see if it's worth starting again and doing it differently or more carefully or just chucking it away.
John
-