R E C A P   
Really Easy Color Adjustments for Photographers
The following demonstrations are intended as reference for AOS award photographers, individuals involved with scanning AOS award slides, and anyone else who wants to quickly & easily correct digital images for exposure-contrast-color balance. These demonstrations assume that the user A) has a basic understanding of computers B) appropriate image editing software [Adobe Elements,  Photoshop, Photoshop LE, Paint Shop Pro, PhotoImpact, etc.]  C) created the images being adjusted or have familiarity with the subject. Although most digital image editors have far more power and capabilities than will be shown here, we will only cover the most basic features that enable us to achieve good looking digital photos. Demonstrations are shown on a PC, for Mac substitute Cmd key for Ctrl.  You will need to evaluate results. If there was not some skill and judgment involved in the process, then a computer would automatically turn out perfect photos.

PC Keyboard shortcuts:     Ctrl+C = Copy   |    Ctrl+V = Paste    |    Ctrl+X = Cut    |    Ctrl+Z = Undo 

A good place to start image adjustments is Auto Levels.
Go Image
> Adjustments > Levels, then hit the Auto button. In Photoshop, you may also use the keyboard shortcut:
Shift+Ctrl+L

Often, this is all you need to correct an image for exposure-color-contrast.

If the image  looks good, hit OK. Otherwise close dialog box and go to the next step.

The three Sampling eyedroppers can often quickly set color balance and exposure.
Go
Image
> Adjustments > Levels,
In Photoshop, you may also use the keyboard shortcut:
Ctrl+L

If your image has true dense black some- where, use the black eye- dropper to sample it.

If the image  looks good, hit OK. Otherwise close dialog box and go to the next step.

 

 

 

 

 

If your image has neutral gray somewhere, use the gray eyedropper to sample it.

If the image  looks good, hit OK. Otherwise close dialog box and go to the next step.

If your image has pure white somewhere, use the white eyedropper to sample it.

The eyedrop- pers will adjust whatever color you sample to black, white or neutral gray.

If the image does not look good, go to the next step. You can also use the eyedroppers as a first step to quickly set color balance then fine tune with RGB Levels.

 

If the preceding steps do not produce a good looking image, or if you wish to fine tune other adjustments, Levels provides a quick and easy way to do this. You may also use Curves which can provide more control, but the adjustments can be hard to get used to. 
Go Image > Adjustments > Levels or Photoshop Ctrl+L.

The histogram, or curve, has 4 channels: (Red, Green, Blue) that make up the image, plus the RGB channel combining all 3. Ideally, the curve should begin at the ends, without any flat area. Moving the RGB sliders adjusts exposure & contrast.

Moving the left RGB slider in to the beginning of the curve makes it darker &  contrastier.
Moving the right RGB slider makes it lighter & contrastier. Moving the middle slider left or right makes it lighter or darker without adding contrast. You can do these adjustments on each color channel to correct color cast or fine tune color.
Auto Levels, our first demonstration, sets levels by moving the sliders in on each channel to eliminate the flat and have the histogram begin at the toe of the curve. For many images this works, for images with strong color cast, old or faded images, images shot under inappropriate lighting for the camera setting, etc. You will need to use human judgment and evaluate results as you adjust extreme images.
Highly saturated colors, especially reds, oranges & yellows, can look unnatural and be difficult to print. By slightly desaturating the image you can achieve a more natural and easier to print photo.

Go Image > Adjustments > Hue/Saturation In Photoshop, you may also use the keyboard shortcut:
Ctrl+U

 

 

Desaturate using the middle slider. Moving to somewhere between -5 and -15 usually creates a better looking photo.

To finish your image and give it a nice crisp look, use Unsharp Mask. Go Filter > Sharpen > Unsharp Mask.

Bigger images will need more sharpening.
DO NOT oversharpen!!! For a screen resolution image - Amount = 30 to 45 is enough. Set radius 1.5 to 2.5 and Threshold to 5.

 

 

 

 

Be sure to save the file using a meaningful name. Be careful not to overwrite any files that may be higher resolution with the same name.

These methods can be used to correct images without degrading image data as severely as other editing tools.  Avoid image processing using Color Balance or Auto Color, Brightness/Contrast or Auto Contrast, and the Sharpen or Sharpen More filters.