When to use gray gamma 1.8 or 2.2 for digital negatives

Regardless of the workflow you use to make digital negatives, consistency in the negative is the key to achieving repeatable results in your photographs. It’s worth questioning whether or not the original step wedge was made in gray gamma 1.8 or gray gamma 2.2.

Writer and photography / Scott Barnes

Regardless of the workflow you use to make digital negatives, consistency is the key to achieving repeatable results. Much has been written about color management, but most of it focuses on printing. Since much of the process of making digital negatives involves using some sort of gray scale step wedge, it’s worth questioning whether or not the original step wedge was made in gray gamma 1.8 or gray gamma 2.2. If you download a step wedge from the Internet, or buy one that comes with someone’s digital negative system, you may not know if that step wedge was made in gray gamma 1.8 or gray gamma 2.2. Even if the step wedge was made in an RGB color mode, the gray gamma still makes a difference. The person who made the step wedge had a specific gray gamma set in Photoshop. Hopefully, the creator of the step wedge will share both the RGB color setting and the gray gamma setting. But, if they did not, then you can use the info panel to figure out which gray gamma they used.

1 Launch Photoshop.

2Click Edit → Color Settings.

3Pay attention to RGB and Gray Gamma settings. Gray Gamma is the most important one for gray scale step wedges. Make a note of the RGB used, so your workflow can be consistent.

4Open the step wedge.

5Click Window → Info (F8) to open the Info Panel. When the Info Panel appears, pay attention to the K value.

6Mouse over the various rectangles in the step wedge.Each value in the step wedge should match the value that appears after K in the Info Panel. For example: if you mouse over 50% in the step wedge, then in the Info Panel you should see 50%.

7Right numbers? If the numbers don’t match, then either the step wedge was not built accurately, or (more likely) the Color Settings that you are using in Photoshop do not match the color settings that were used to create the step wedge. For example: if you mouse over 50% in the step wedge, and the Info Panel reads 57%. The color settings need to be corrected so both numbers are the same.

8No match? If the numbers don’t match, then go to Edit → Color Settings and change the Gray Gamma setting. Go back to step 6 to see if the value for K is the same as what it is supposed to be in the step wedge. If you have gone through all gray gamma settings and the numbers still do not match, then consider building your own step wedge with the color settings that you normally use in Photoshop.

Good luck!

The author Scott Barnes is currently teach Printmaking, Photography, and Life Drawing at Fairleigh Dickinson University in New Jersey. During the summer (and between semesters in the winter) he alternate between teaching leadership skills to young adults and giving various art workshops. Most of his own art is about engaging the natural world, with the aim of promoting higher respect for it.