When one is faced with a task such as this, it is important to start by carefully analyzing the problem. I'll often try to state the problem to myself in as simple, accurate, and actionable terms as possible. In this case, I described (to myself) the major problem as "brighten and add yellow to the bottom half and (viewer's) LHS of the dress, especially the darker areas".
A statement like this is almost a direct roadmap of the tasks ahead. For example, from it, it is clear that one will have to make separate selections (equivalent to layer masks) of the areas mentioned. So, developing these was the very first thing I did. Here are the layer masks I used:
a) The entire dress - needed to build the other masks, as well as on its own to prevent unintended changes to the white background :
b) Emphasizing the bottom half with a smooth transition to no efx applied to the upper half of the dress:
c) Selecting just the bottom edge of the dress and underlying material for separate, extra brightening and color treatment:
d) Selecting just the lower left hand edge (ie, towards the rear of the dress) for separate, extra treatment:
e) To emphasize the shadow areas in the various adjustments that need to be made, rather than making a luminance mask (which I would have done had the selection problem been more difficult), I simply used the Blend-IF sliders in the layer properties of almost all of the adjustment layers that I used:
The next step is to decide on which will be the best methods to use "to lighten" and "to add yellow" in the various areas. As usual, in PS, there are many, many different ways to accomplish these tasks. To be honest, the only real way to select the best approach for a particular situation is to have extensive experience with the various options, and chose from among them on the basis of "best intended effect", "fewest unwanted / unintended side effects", "ease/speed of use", "general availability", etc.
As an example, to accomplish brightening, I could have used any of the following types of adjustment layers: "Curves", "Levels", the brightness slider in a "Brightness / Contrast" layer, or many other approaches. I didn't need the exquisite control that "Curves" offers, and I hate the brightness slider in "Brightness / Contrast", so I used several "Levels" adjustment layers (ie, one for each of the above areas listed).
To accomplish "adding yellow", again there are dozens of different ways to do this using only Photoshop's native tools, and hundreds of different ways if you include third party add-ins. I decided to use a "Color Balance" adjustment layer primarily because it's fast, simple, and I know that it allows one to easily target only the shadow areas.
So, my approach was to simply go through the various areas (listed above), and add separate, appropriately masked "Levels" and a "Color Bal" adjustment layers for each area.
BTW, don't let the above description intimidate you. This approach sounds much more difficult and time consuming than it really is. In actuality, it probably took me only 5 minutes to do the work and 30 minutes to write up this description of my general approach. Writing up a full tutorial would take even longer, and, unfortunately, I just don't have the time to do it.
Besides, IMHO, learning a general approach like this will likely be more useful in the long term than having to plod through a detailed step-by-step tutorial and then figure out for yourself why the instructor did what he did.
HTH,
Tom M
