Hello (again),
The Tint parameter for Arri Skypanels is a little wonky as defined in the current profiles, and could use a look. One of the issues appears to involve a fairly significant bug which could affect any parameter in any profile. I think I've gotten a pretty good handle on what is wrong, but there are a few parts to it, so please pardon the length of this post.
tl;dr:
For Skypanel profiles which include the Tint parameter: (these are values for the 16-bit modes; the values for 8-bit modes will be different)
1) Change the home value for Tint to 35268.
2) Change the range so Min is 5001, and Max is 65535 (those values are currently reversed).
3) A serious bug occurs when the home value is outside the range of the Min and Max values, as is the case in the current skypanel profiles for Tint (details below).
Here's a download link to the manufacturer's profile definitions: www.arri.com/
And now the long version:
I took all these notes working with the profile for Skypanel S60-C in mode 6. The profiles which have Tint are modes 1, 2, 3, 11, 12, and 13 (8-bit), and 6, 7, and 8 (16-bit). All the values mentioned here are 16-bit, but I checked a few of the other modes with Tint and they all had the same issue. I didn't check the profiles for the S30-C, but they are functionally identical to the S60 so the problem likely exists in those profiles as well.
Home value: given that the user range for Tint is from -100 to 100, with neutral or 0 in the middle, it makes a lot more sense to have the home value set to user value 0, or DMX 35268. As a partial consequence of the bug, the current effective home value is the Min value 65535, which is full green, and starting the light that way by default is almost never desirable.
Range min/max: Magenta correction is universally referred to as minus green, and green correction as plus green, so having these reversed is what my dad called bass ackwards. Min should be 5001 (full minus green/magenta) and Max should be 65535 (full plus green). This also corresponds to the manufacturer's terminology in the parameter definition.
Bug: This is the biggest issue by far--having a home value that is outside the range between the min and the max causes very undesirable and unexpected behavior where the DMX values do not change over the entire user value range.
To see this bug in action, do the following:
1) Patch channel 1 to address 1 as an Arri Skypanel S60 C M6.
2) Live, Channel 1 Enter. Tap the About key, and click on Current Values.
3) Note that Tint's DMX value defaults home to the defined Min value 65535, user value -100.
4) Run a slow fade on Tint up to the max value (100).
5) Observe the values for Tint as they change:
- At a little past user value -54, the DMX value passes through the midpoint of the actual range (35268), which indicates the light outputting neutral green/magenta correction, what should be user 0.
- At around user value -7.6, the DMX value hits the defined max of 5001, or full magenta correction.
- As the user value increases from -7.6 through zero and up to 100, the DMX value does not change, and stays at 5001.
As this behavior is deeply problematic, it would probably be a good idea for the software to never let the Home value be set outside the range of the Min and Max values.
Thanks for reading this, and I hope the correction to the Skypanel profiles can be made without too much trouble, and the bug isn't too difficult to squish.
Cheers,
Matthew Rohn
IATSE Local 52
