In the critique forum GB1 suggested I post something to show how I achieved the results for Orchid art. It was actually a lot of hit and miss experimentation and I didn't save the file before merging the layers so I'm not sure of the exact settings used. Instead, I've picked another photo and documented the steps all the way through, so the process is maybe a little more concise and understandable for others. All the same principles apply to both photos, but the adjustments (and therefore results) are nearly infinite. This is not meant to be an EXACT how-to tutorial, but more of a starting point to get your imagination going in it's own direction.
Applying texture overlays to get a more dramatic effect
Start by selecting the images you think you want to use.
In this case, kind of a ho-hum arched walkway in downtown Ft Lauderdale, a large rock I happened to see in my travels, and the concrete they are getting ready to refinish outside the building I live in.
1) Rotate and level the background image
2) Copy the rock image and paste as new layer, then set blend mode to screen and reduce the opacity (in this case 71%).
3) Blur this layer out (Gaussian - radius 5+/- or whatever) [note: see step 7!]
4) To counteract the sceen layer lightening the image too much, duplicate the screen layer, and set blend mode to Burn, further reduce opacity to suit (in this case 43%) and blur it further.
5) Copy the third image and paste as a new layer. set blend mode to overlay and reduce opacity until you can still see it, but it's not overly obtrusive (in this case 79%)
6) Take the eraser, set to large with a hardness of 0 and randomly remove portions of the layer containing the third layer to taste.
7) I've decidded that the image is way too orange, and want to get it back to something more believable, so I returned to layer one (the orange rock and applied sepia toning set to age 60 yrs. This keeps the warmth but loses the orange cast.
8) Use the paint brush at different sizes/densities/opacities to add highlights, keeping in mind that each layer will produce a different result with the same brush (screen/burn/overlay)
9) At this point it's time to adjust contrast overall color, highlight/midtone/shadow, saturation, etc. Not sure about photoshop, but in PSP X2 there is a "smart photofix" that works suprisingly well at allowing you to adjust most of these paramiters all at the same time. You can do this layer by layer or all at once, so for the sake of brevity, merge all layers (flatten)
10) Make the bulk of the adjustments (manually or automatically)
11) The image may still look a little more muddy than you'd like, so try bumping the contrast to define the "grunge"
12) Crop, resize, sharpen, done... :thumbsup: