Length of custom gamma table. 0x0568-0x056D ∙ 1384-1389
For scanners that support downloadable gamma correction curves, IG_ISIS_TAG_GAMMA_TABLEn specifies the data for each element of the downloadable gamma table.
IG_ISIS_TAG_TYPE_LONG
Drivers for scanners that support at least one downloadable gamma table.
A list of value, each with valid choices in the range of 0 - 255, that specifies the data for a downloadable gamma correction curve. Each tag in this group has a number of elements equal to the length value in its corresponding IG_ISIS_TAG_GAMMA_LENTHn tag.
Inverted linear gamma curve
256
255
254
253
<... values continue to descend...>
2
1
0
The first line in the file is the description of the gamma curve. The other lines are the actual gamma table data.
There are currently six tags in this group: IG_ISIS_TAG_GAMMA_TABLE1 through IG_ISIS_TAG_GAMMA_TABLE6. To create a downloadable gamma table, establish a length for the table, then fill in the values for each element of the table by calling IG_ISIS_tag_set_long. You can also let the user select an existing gamma file by calling IG_ISIS_drv_read_gamma_file. For more information on downloadable gamma tables, consult the documentation supplied with scanners that support downloadable gamma tables.