These are all the possible values for the IG_ISIS_TAG_GAMMA tag.
Values:
| IG_ISIS_GAMMA_AUTO | Scanner's gamma correction is set to automatic. |
| IG_ISIS_GAMMA_DOWNLOAD1 | Scanner's gamma correction is set to the first downloaded correction table. |
| IG_ISIS_GAMMA_DOWNLOAD2 | Scanner's gamma correction is set to the second downloaded correction table. |
| IG_ISIS_GAMMA_DOWNLOAD3 | Scanner's gamma correction is set to the third downloaded correction table. |
| IG_ISIS_GAMMA_DOWNLOAD4 | Scanner's gamma correction is set to the fourth downloaded correction table. |
| IG_ISIS_GAMMA_DOWNLOAD5 | Scanner's gamma correction is set to the fifth downloaded correction table. |
| IG_ISIS_GAMMA_DOWNLOAD6 | Scanner's gamma correction is set to the sixth downloaded correction table. |