1. Please Note These definition power points may not cover every artistic term or Photoshop term discussed in class. These are just the terms we really did see within a Power Point slide show. There are too many PS terms to list definitions of. You can easily hover over a tool in PS and it will tell you what the tool does. There are also many resources on the internet to help you learn PS. This is just an aide meant to help, but students are responsible for taking their own notes in class. And for copyright reasons, I cannot post artworks, but you can look them up online with the title and artist I refer to.

2. The Levels Command in Photoshop

3. Levels. Levels is one Photoshop image adjustment
Levels Levels is one Photoshop image adjustment command tool that allows you to modify contrast and value qualities of an image. The Levels command is found within Adjustment folder of the Image drop-down menu.
Histogram a graph of contrast found within Levels command
Gamma The grey slider in the middle of the X-axis in a Histogram. It represents the mid-tones. In a black and white image, it is used to adjust values of grey that lie between absolute black and white. It changes the overall value of a black and white image. For a color image, it is values of color.
Mid-Tones The values of grey (in a black & white image) or values of color (in a color image) that fall between absolute black and white.

4. Levels
Levels is just one tool that allows you to adjust the contrast of an image or the value of its colors. The Curves command can also do this.
We use a black and white image to initiate an explanation. The following slide shows a low contrast black and white image. Notice the data graph (called a Histogram) on the upper right.
The black triangle represents absolute black, the white triangle represents absolute white, and the grey triangle represents different values of grey in between them. Thus the X-axis represents values of grey measured from 0 to The Y-axis represents how many pixels are have any one of those particular values of grey. Thus, this Histogram reveals that this photograph has not absolute black or white pixels, but rather a lot of mid-level greys. The image supports this, we visually confirm that this image has low contrast.

6. Levels
Levels allows us to make adjustments to the Histogram if we desire to change the contrast or value of the photograph.
If we desire to improve the photograph’s contrast, we can slide the black triangle (that represents absolute black) to the right till it just touches the base of the slope of the data on the left side.
We can also slide the white triangle (that represents absolute white) to the left till it just touches the base of the slope of the data on its right side.
Thus, we have remapped the image data so there will be absolute black and absolute white, and greys are distributed between them. The result is we have good contrast in the photograph.

7. After making the Levels adjustment we just discussed we get the following result in the photograph and its Histogram.

9. Levels
Finally, once again, the grey slider (often referred to as Gamma) in the middle represents values of grey between absolute black and absolute white (these grey values are often referred to as the Mid-Tones).
You move Gamma (grey-tone) slider left or right if you want to make the overall photograph darker or lighter.

10. Levels for use with Color Images

11. Levels
The same principle applies to using Levels for a color image.
The following slide shows a low contrast color image. Notice the data graph (called a Histogram) on the upper right.
The black triangle still represents absolute black and the white triangle still represents absolute white because if you push a color to the extreme of its value, one direction or another, the color increases in value and ultimately approaches black or if you push its value the other way it decreases in value and approaches white. The Gamma (grey slider) represents all values of a color between black and white.
Thus, this Histogram reveals that this photograph has not absolute black or white pixels, but rather a lot of mid-level colors. The image supports this, we visually confirm that this image has low contrast.

13. Levels command with Color Images
Levels allows us to make adjustments to the Histogram if we desire to change the contrast or value of the photograph.
If we desire to improve the photograph’s contrast, we can slide the black triangle (that represents absolute black) to the right till it just touches the base of the slope of the data on the left side.
We can also slide the white triangle (that represents absolute white) to the left till it just touches the base of the slope of the data on its right side.
Thus, we have remapped the image data so there will be absolute black and absolute white, and mid-tone colors are distributed between them. The result is we have good contrast in the photograph.

15. Levels command with Color images
Finally, once again, the grey slider (often referred to as Gamma) in the middle represents values of colors (R,G and B) between absolute black and absolute white (these values are often referred to as the Mid-Tones).
You move Gamma (grey-tone) slider within the RGB folder left or right if you want to make the overall photograph darker or lighter.

16. Levels command with Color Images continued…
A thing that makes a Histogram different for a color image is that you can adjust the contrast of the entire image with R,G and B combined, or you can just adjust one of those three colors.
Remember, that all the colors in a color Photoshop file are made by mixing the colors R,G and B in some ratio. That may be hard to believe, but it is true.
You can go directly to the R, G or B specific folder to make an image more red, more green or more blue, or less of one of those colors.
There is more to discuss about adjusting color photographs. You have to understand the relationship between the colors RGB and CYM (cyan, yellow, and magenta). But, that is the topic of another lecture.

17. End of this slide show