Image retouching, photo restoration, and image reproduction are all forms of delicate image manipulation. It is the art of improving the image without going too far. Although the definition of 'too far' is subjective and can vary widely, at some point there is common ground where everyone would say "That's just not right!"

So how do you define 'too far'?

When you go too far, you destroy useful image data and misrepresent the original. This can occur from smoothing so much that the texture doesn't match surrounding areas; it looks like bad plastic surgery. The retouched area has smudged pixels without the image noise and the surrounding areas have some level of grain or noise.

Misrepresentation of the original can also occur when you incorrectly reconstruct a portion of the image (ex. Correct an eye). Even subtle asymmetries can be registered by an observer; they may say that image just doesn't look right, but not be able to explain why. Reconstruction of a person's eyes is a good example. If the pupil is too big, misshapen, offset too far to the right or left, it has a high percentage of registering as out of place with the viewer.

Just like plastic surgery, if you over correct an older individual's image, it will also register as incorrect with your viewer, even if they don't know the subject personally. If you remove the wrinkles from a 70 year old face or eliminate the crow's feet, you have made a 70 year old look like a very fake 40 year old. This is because you are not modifying the facial structure to match and you shouldn't.

The job of the retouch artist is to improve the image while maintaining consistency throughout the image and subject. The image noise or texture is maintained, 'age appropriate' modifications are made, and distracting features are subdued.

Just This Side of Too Far is when you have minimized the distractions and let the important features of the image stand out. This is accomplished by:

- Correct the color balance, exposure, contrast, and black point before starting to retouch.

- Working on small sections of the image with no sweeping changes (ex. Size of a freckle).

- Cloning equivalent areas of the image to reconstruct which avoids the smudging (ex. A cheek).

- Apply only successive low opacity adjacent clones to subdue a feature (ex. A crease).

- Following up the micro changes with minor adjustments at normal magnification.

- Group related changes in a dedicated image layer, then reduce the opacity of the specific change to better blend the changes and bring an effect back from too far to just right.

- Progressively build up many layers at appropriate opacities to attain the final product.

There is specialized knowledge for different types of retouching. For example, with portrait retouching there are elements of a face that people are sensitive to:

- A clean, smooth chin

- Wrinkles, bags, shading under the eyes

- Crows feet on the edge of the eyes

- Whiteness of the eyes and teeth

- Shading and highlights on the ridge of the nose

- Imperfections on the nose

Today's graphical software tools allow someone to produce images with good retouching, but it takes time and experience to learn what is important to retouch and how far to go, as well as, being able to do the work efficiently.