Leo's Favourite Flower for February 2013

Started Feb 1, 2013 | Discussions thread
Gerry Winterbourne
Veteran MemberPosts: 7,524
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Intro to PP
In reply to ilikespam, Feb 23, 2013

PP is something you can spend a lot of time learning for some really sophisticated effects or something you can keep to an absolute minimum, just for a few basic tweaks.  I'll stick to just a few basics.

There are lots of different image editing packages: makers always provide one with the camera, and for DSLR cameras the package includes a raw converter.  All these packages differ in many ways but the principles are more or less the same, although the user interfaces vary a lot.

I use ACR (Adobe Camera Raw), which is the raw converter in LR4 and CS6 - there's a slimmed down version in PSE10.

Modern cameras are good at white balance and AWB will usually get you an accurate result but it's worth understanding how to adjust WB.  There are two sliders: one controls how cool or warm the image looks - cool is bluish, warm is yellowish.  The sliders alter colour temperature and the steps are quite big - 500K doesn't usually show that much change.

In this example the middle view is WB as shot; left has temperature down by 1000K - see how the greens look quite blue - and right is up by 1500K and they look distinctly yellow.

The other slider is tint, from green to magenta, and goes in much smaller steps.  Here the middle is again as shot, left is down by 20 and right up by 20.

Once WB is OKyou need to set white and black points.  Essentially, you are getting all the data in the raw file into the 256 steps of an 8-bit device (your screen or printer).

Here's a shot that I deliberately underexposed -1.5EV to preserve detail in the overcast sky.  The left view shows it as shot (after a small tweak to WB).  Then I increased the exposure slider 0.75EV until the right hand end of the histogram almost reached the edge [some PP can increase luminance slightly so although you want to go all the way out in the final version it's best to leave a small safety margin at this stage]; then I increased the black slider to try to avoid black clipping (which I couldn't quite manage).

That's got the ends of the histogram OK but the image looks dull.  The real art of PP is managing the contrast between the ends of the histogram.  The easiest way is with the contrast slider but, paradoxically, that isn't the best way to adjust contrast.

Using a tone curve takes more practice but is more flexible.  Here's how I handled this one; the top right I kept as before to preserve the sky.

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Gerry
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First camera 1953, first Pentax 1985, first DSLR 2006
http://www.pbase.com/gerrywinterbourne

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