Color Correcting... the 'Correct' Way!

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Color Correcting... the 'Correct' Way!

Post  PeteJones.ca on Wed Mar 12, 2008 11:04 pm

Before we get into color correcting your images, there are a couple of things you should do first. they only consist of a couple of clicks, but don't underestimate their impact. These steps are essential to getting accurate color corrections in Photoshop... sorry - I only speak to those using Photoshop...

First things first... grab your Eyedropper tool. Now, under normal circumstances the default sample size setting for this tool, (point sample), would be fine to grab a color of a specific pixel, but it's not what we're looking for when it comes to color correction. You'll need to go to the options bar for the Eyedropper tool, under the Sample Size pop-up menu, and change it to a 3 by 3 average. This will give us a reading representative of the 'area' under the Eyedropper tool, as oppossed to a single pixel value.

The second part is configuring Photoshop, visually, for color correction. You don't want a colorful background when you're trying to color correct an image... a colorful background can change the way that you perceive colors, and well... I think you get the idea. So change the background of your working area to a neutral gray. You can do this by simply entering 'full screen mode' in Photoshop, by maximizing Photoshop (for PC users). If you're a Mac user... I think you can press 'F' once to enter full screen mode, and 'F' twice to exit.

Okay... so now you're ready to color correct!

Open your RGB photo, and select IMAGE > ADJUSTMENTS > CURVES. Now we need to set a few preferences in this dialog before we can continue. Let's start by defining a target color for our shadows. To set this... double-click on the black eyedropper tool (it's on the lower right hand of the dialog box - the first eyedropper of three - on the left). A color picker will appear asking you to select Target Shadow Color. Here we will enter values that, when applied, will help remove any color casts your camera introduced into the shadow areas of your photo. Enter the following values into the R, G, and B fields:

R: 20
G: 20
B: 20

Click OK. These figures are evenly balanced (neutral) and prevent your shadow area from having too much of one color (which is what casues a color cast). Additionally, these values I'm giving you, will help your photos maintain enough shadow & highlight detail for a printing press (incase you're going to use them in a brochure, magazine, cover, print ad etc.)

Now we'll set a preference to make our highlight areas neutral. Double-click on the white eyedropper tool (the third of the three eyedroppers in the lower right hand of the dialog box... where we found the black one). Enter the following values:

R: 244
G: 244
B: 244

Click OK to set these values as our highlight target. Now we can set our midtone preference the same way we did with the shadow & highlights. Enter the following values for the middle eyedropper tool:

R: 133
G: 133
B: 133

Click OK to define our target midtone values. Next we're going to let Photoshop tell us where the shadow, midtone, and highlight areas of your image are. Go to the layers palette and click on the half-white/half-black circle to bring up the Create New Adjustment Layer Pop-up menu (it's the fourth icon from the left at the bottom of the layer palette). Now choose threshold from the pop-up menu.

Drag the threshold slider all the way to the left until your image is completely white. Now slowly drag it to the right until you start to see some of your image reappear. That's photoshop showing you exaclty where the darkest part is. Click OK to close the threshold dialog - this adds an adjustment layer - no problem... we'll delete it later, your photo has not been altered (yet).

Now that you know where your shadow area is, you can mark it. Do this by clicking (and holding) on the eyedropper tool, the fly-out menu will appear. Select the Color Sampler Tool from the fly-out menu. Click this tool on the area of your photo that is darkest and a target cursor will appear, marking that spot. When you do this the info plalette will appear... you can close it - you don't need it.

Now, to find the white area in your image, you simply use the same technique to find the highlight areas. you can double-click on the adjustment layer thumbnail to bring up the threshold dialog again. (the thresholod slider will need to be moved to the right this time, instead of the left). Apply the adjustment layer, once you've found the highlight, by clicking OK. Now use the color sampler to mark the highlight area.

Now you're done with the Threshold Adjustment layer, so you can delete it by dragging the adjustment layer onto the trash icon in the layers palette. (click yes when warned about the deletion) Now your photo looks normal again, except that it has two target markers on it. Now bring up the Curves dialog: IMAGE > ADJUSTMENTS > CURVES.

First, select the shadow eyedropper (the one half filled with black) from the bottom right corner of the curves dialog. Now click once directly on the center of the No. 1 target and the shadows area will be corrected. If you click the No. 1 target and your picture looks like crap, either you've clicked in the wrong spot, or what you thought was the shadow area, wasn't. Undo the command by pressing Control-Z and try again. If that still doesn't work, chill... just keep clicking areas that look like the darkest until things look right (you can use this with the midtones and highlights too).

While still in the curves dialog, switch to the highlight eyedropper (the one filled with white). Move your cursor onto the photo and click once directly on the center of the No. 2 target to assign that as your highlight. Good - you've defined (and corrected) your shadows and highlights... now onto the midtones...

Grab the midtones eyedropper from the curves dialog and try to find an area in your image that looks medium gray. Doing this will correct the midtones and can be either a dramatic, or subtle difference. Unfortunately, not all images have an area that's gray, so you won't always be able to correct the midtones.

One more importnat thing before we finish and click OK.... in the curves grid, clcik on the center of the curve and drag it upward a bit to brighten the midtones. This is a visual adjustment, so you need to determine how much is enough. Kepp it subtle, just enough to brighten the midtone detail and 'bring it out' a bit. now click OK!

That's it, you're done (you can remove the two color sampler targets on your photo by going up to the options bar and clicking the Clear button.

From time to time I'll be posting valuable goodies like this on the Digiscope Diary Forum, so stay tuned and support the community that Rob has worked so hard to provide as all with!
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Re: Color Correcting... the 'Correct' Way!

Post  Admin on Thu Mar 13, 2008 4:20 pm

Thank you so much Pete for your input.
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