| Author | Message | ||
     Wilbur C. Andrews New member Username: Captnwill Post Number: 1 Registered: 03-2003 |
Jonathan, 1. When editing 48 bit files, do the transformations work on all the 16 bits per channel? I ask this question because Photoshop has some strange algorithm with these files that map all 2^16 values for a pixel into 256 discrete steps (0..255). Their responses to questions about this have been less than satisfactory. Since PWP's values are displayed as percentages, I assume that you just apply that percentage to all 2^16 values. That is, if the original pixel had a value of 65,535 and an editing function of 51% was applied to it, the resulting value of that pixel would be 33,423. If this is correct, there is a major difference between the way PWP and Photoshop handles 48 bit files, and maybe you should talk about as a reason for using PWP. 2. Are all these calculations done in integer arithmetic? 3. How does PWP know how to do the math on 16 bit TIFF files that have only 10, 12, or 14 bits per channel? Thanks, Wil | ||
| Jonathan Sachs Board Administrator Username: Admin Post Number: 515 Registered: 08-2002 |
>> When editing 48 bit files, do the transformations work on all the 16 bits per channel? Yes >> Since PWP's values are displayed as percentages, I assume that you just apply that percentage to all 2^16 values. Yes >> Are all these calculations done in integer arithmetic? Yes >> How does PWP know how to do the math on 16 bit TIFF files that have only 10, 12, or 14 bits per channel? If there are less than 16 bits per channel, the data are always stored in the most significant bits. Jonathan Sachs Digital Light & Color |
