More Dicking Around In The Darkroom

I know that several of you are expert in Photoshop (indeed one of you has achieved the rank of Jedi Master), but some of you seem to like this sort of post so I'll keep doing them from time to time.

One of the most popular (and simplest) things people use Photoshop for (at least at home) is correcting the colour on photographs and repairing and retouching old photos that have been scanned in. I'll be dealing with the old photo thang a little later but for now (as I am too busy to do a big post) let's just explore a few ways of

tweaking the colour in photos that have somehow gone astray in the tone department.

The commonest cause of this is pictures taken without flash under fluorescent lights. Fluorescent light tends to give a green cast on daylight film and even modern digital cameras pick up on it.

However, when we visited the magnificently monickered "Le Palais du Fruits" opposite Katie's favourite breakfast café on Rue Montorgueil in Paris, we discovered they use a weird pinkish red fluorescent lighting, presumably to keep the fruit fresh though I have no idea why really.

Anyhoo … looking at this just makes my eyes angry so let's make it a little more visually acceptable.

To correct aberrant colour, most people head for the simplest solution and use the "Auto Colour" tool shown here.

The result is usually pretty good though as tools go it is a little like fixing your TV by banging on the top of it.

Sometimes it works, but there are other, more subtle methods which will give a much better result.

Immediately below the "Auto Colour" tool in the drop down menu is an amazingly good tool called "Curves."

This is the little pop-up screen that you get when you launch it. As well as lots of preset options in the top menu you can play with each individual colour using the "Channels" drop down. We're working in RGB here, so we just get the three colours to play with, but that's quite enough.

First up: let's get rid of some of that red. Simply select "Red" from the drop down channels menu and drag the line off to one side. To the left increases the redness and to the right decreases it.

Of course you can add multiple points on your line and make really swirly lines to finely adjust each colour but we don't need that here.

The result is a whole lot better but the greens need a little tweaking, too, so we grab the green line and move it

up a little.

Yay! Much better than the original and more finely tuned than the "Auto Colour" tool.

Another option (before we get into the really complex world of adjustment channels in a later post) is the method I probably use most, at least for quick-fix colour tweaking for blog posts.

Below the "Curves" tool is "Colour Balance." This does exactly what it says. Open it up and you get three sliders (if you're in RGB mode) and three buttons for shadows, midtones and highlights.

You can see where I'm going with this one, can't you?"

A few quick tweaks and you've got the photo almost right. Yay!

Fine tuning any of the above methods can be done using the "Hue/Saturation" tool (again, we'll get on to far

more powerful contrast, colour and saturation tools another day).

With this, you can mess with the colour saturation (see Katie's posts on classic John Hinde postcards for some awesomely oversaturated colours) over the entire range or - as we're doing here - choose to change the saturation of one or more of a whole range of colours.

Those pesky tomatoes in the foreground still need desaturating so a quick tweak of the slider puts that right. Later we'll be playing with the sponge tool which I could have used to desaturate individual tomatoes, but that's enough for today. I've got work to do.

Enjoy your tweaking!