color correction

Remember to work non-destructively... Use Layers

1) Open an image
2) Adobe RGB (1998) color space
3) Clean up dust, scratches, dead pixels, etc.

4) Have info box available
go to the menu: Choose -Window - Info

Settings for the Highlight and Shadow Eyedroppers in Levels:

Your white eye dropper should be set R245, G245, B245
Your midtone eye dropper should be set R133, G133, B133
Your black eye dropper should be set R7, G7, B7

(I used to recommend Highlight 244 and Shadow 8, still works I just am getting in sync with the Kelby book for future students, these numbers still work)

to set - bring up a levels adjustment panel
-double click on the white eye dropper type in settings from above in the RGB spot
-double click on the black eye dropper - follow above instruction
When you say OK, Photoshop will ask if you want to save these settings. Click ok. You will not need to set these again until you upgrade the program, etc.

LEVELS ADJUSTMENT LAYER
1) Open a Levels Adjustment Layer

click on the levels icon in the adjustments panel or go to the bottom of the layer panel and choose the adjustment layer icon and choose levels.

2) Click the white eye dropper (on the left, bottom eyedropper)
hold down the option key and slide the highlight input slider. Everything will turn black. Look for the first place you see white. Enlarge that area to 100%. Set a white point on the area that measures closest to 255, 255, 255 (look to your info panel for the RGB numbers)
3) Repeat using the black eye dropper. This time everything will turn white. Look for black, and set point.
4) Use the middle slider to adjust the midtones.
5) Are there any color shifts? if shot with a digital camera, blue or magenta may tint the image. Use the color channels in levels to tweak.
look at the neutral colors. Do they have a color cast? Use the middle slider in the color channel with the cast.

This was a global correction (we corrected the entire image)

To refine your color correction you may need to go into the individual Red, Green or Blue channel to remove a very strong color cast.

Ocassionally the eyedroppers do not work, if there are no true highlight or shadow area. At that point you can slide the input shadow and highlight arrows to the first point of black on the histogram. Then use the middle slider to adjust the midtones.

Advanced tip: With no true highlight or shadow area to be set, you can go into each channel (RGB) and slide the arrows to the black point in each channel within the histogram. This will give you a more accurate adjustment.

Red Channel:
toward “0” = red
toward “255” = cyan

Green Channel
toward “0” = Green
toward “255” = Magenta

Blue Channel
toward “0” =Blue
toward “255” = Yellow

After making a levels layer adjustment you may want to fine tune the image with a curves adjustment layer.
1) Open a curves adjustment layer
2) Make adjustment

Info about curves:
if you pull the curve down from the center point, the image will get darker.
if you pull the curve up from the center point, the image will get lighter and brighter.

s-curve: makes midtones more contrasty by making the curve steeper and the shadows and highlights less contrasty where the curve is flatter

inverted s-curve: makes the midtones less contrasty and increases the contrast in the shadows and highlights

The angle of the curve controls contrast. If you steepen it, you can increase the contrast in your image; if you flatten it, you can decrease contrast.

In Photoshop CS4, Curves got a lot easier to use because the new on-image adjustment tool this lets you add and move adjustment points by dragging in your image. Just click the button that looks like a pointing hand (top left of the curves adj.panel) to activate this tool and then hover your cursor over the area you want to change (your cursor turns into an eyedropper). A white preview circle appears on the curve (circled, right) that corresponds to the tonal value of the pixels you're hovering above. When you're ready to add a point to the curve, click once.

The curves dialog shows a straight line imposed over the image histogram. The histogram maps out the tones in an image, showing the number of pixels in the image at each tonality from black (on the far left) to white (on the far right.) To adjust the curve, you just click on a point on the line and drag it up or down.

Tip: use the arrow keys to move the points in the curve. Click on a point; it turns black when active; use the arrow keys to move in one point increments.

S-Curve adds contrast

Inverted S-Curve lowers contrast

Correcting images is not an exact science. Many interpretations will work. What feel do you want the viewer to experience from your image? There are no set numbers to pull from everytime; there are guidelines that will help you fine tune your image like using an s-curve to pop the image contrast, but it is up to you to set the points and fine tune the s-curve to that one image.

APPLYING A LAYER ADJUSTMENT TO A PORTION OF THE IMAGE

Use that Layer Mask, one is created with each Adjustment Layer you create.

EXAMPLE of when to do a localized correction: Overall things are looking good but the sky needs more color
1) Open a layer adjustment, a curve for example. While only concentrating on the sky, correct to the desired look -deep blue. The rest of the image will look horrible.

2) Click on the layer mask in the layer. it will have a highlight box around the mask portion of the layer, it is white now revealing the correction to the entire image.

3) Command I (inverts the layer mask) if needed, turns the mask to black hiding the correction.
the image returns to the way it appeared before the adjustment layer. Inverting the layer mask hides the adjustment

5) Click on the paint brush, in the options bar. You may want to lower the brush opacity to paint a partial correction back into the image, building up the correction, more in some areas, less in others. Your layer mask will have gray tones now.

When painting on a Layer Mask remember:
Black conceals
White reveals

Bonus Tip:

Blend Modes of Multiply and Screen

1) open an image that is under exposed or over exposed

2) duplicate the background (command J)

3) use a layer blend mode
     dark image use a blend mode of screen (this lightens the image by approximately 1 stop)
     light image use a blend mode of multiply (this darkens the image by approximately 1 stop)

you can duplicate the blend mode layer to add to the result. You can then use the layer opacity slider to fine tune the result.