Is it better to use the burn tool to tone down bright area than selecting the area of interest and then decreasing the brightness or exposure ? If better, why? I am not refering to blown highlights.
It depends on what you want to achieve. If it is a small spot, the burn tool is fine, but for larger areas, it can be difficult to make it uniform. Also, I don't like the effect in some cases.
I usually find it better to do a feathered selection or refine edge selection, then use the shadow/highlight tool in PS, or simply use the curves tool. The curves tool is a great tool and one can do a lot of things with it, once you learn the details of how it affects images.
Sometimes to avoid a color shift in these applications, I switch to LAB mode and do the application of the tool on the luminance channel.
For a couple other options I find the adjustment brush in ACR works well for making adjustments to a bright area or to bring out a bit of detail in darker areas.
You can also sometimes bring a bright area down a bit with S/H adjustments.
I'm in agreement with Dave, at least partly. The ACR curves adjustment is most useful, the Lights and Highlights sliders specifically. Although the adjustment brush is indeed useful, especially for small spots, with larger areas it leaves unblended edges. The spot removal tool can be useful as well, as long as you are careful to pick an appropriate source.
In any case you will have a distinct disadvantage when you open in PS and try to do adjustments as opposed to in ACR itself. For example use of the Shadow/Highlight tool is much more likey to produce artifacts like halos, and for some reason the simple coversion from RAW to PSD seems to partly reduce some artifacts as well.
Bottom line; do as much adjustment as possible in the RAW converter.
regards~Bill
Following on from Chas' suggestion, here's another one which works particularly well for human faces. Say you have a portrait with side lighting and there are patches of highlights (some could be blown) on the light side. Pick up some face colour with the eye dropper tool and with a soft paint brush set to Color blending mode, brush over the highlights. With the this blending mode you lay color down but it does not affect detail. You can of course set the bush parameters of opacity and flow to <100 which will decrease the effect as you brush away. This is also an excellent way of hand colouring b/w images, almost like the old days!
The Brush with Color blend mode can be used to go over an area after burning or darkening the highlight areas, as frequently these areas can start to gray out. Adding a bit of color back in helps to make these altered areas appear more natural.