I guess there's one other thing to point out, something I thought about mentioning back when we were talking about color control in UF. While it's true that UF does not have the same kinds of color control you have in Photoshop, there are still things you can do with "color adjustment layers" that allow you to globally tweak the colors of all the layers underneath them. I often use these to brighten, darken, saturate, hue-shift, or color cast entire images all at once. I had a nice write-up of it somewhere but it's not right in front of me. The basic technique is pretty simple, you just slap a layer of solid color onto an image, and choose the merge mode to obtain the desired effect. Then you adjust opacity to taste.

white + overlay = boost contrast

black + normal = darken

white + normal = wash out

(HSL: 0/128/128) + HSL Add = no change, but from here you can tweak the color to do lots of things. Change the hue = hue shift, change saturation = saturate/desaturate whole image, change the lightness = add/subtract lightness to whole image

white + difference = invert image, this also flips the hues to their opposites; combine with an HSL add layer above set to HSL 180/128/128 and you restore the hues while inverting the lightness.

solid color + hue = force entire image to one hue (reduce opacity to allow limited range of hues centered on layer's color)

solid color + color = force entire image to one hue and saturation (similar to above)

There are more combinations but these are the most important. And because it's a layer, these effects are "on top of" whatever changes are made to individual layers and gradients. It's not as versatile or precise as Photoshop's color controls, but when postwork isn't practical or desirable, it's a nice option to have.

--Damien