colour shifts with multimachine rendering

[Lars Bunch]

Hi,

Is it possible it is the lossy nature of the jpeg files that may be causing the problem? If you render as an uncompressed Tiff sequence do you get the same color shifts? (If you need jpeg, I suppose you could convert to jpeg on a single machine after the main render is complete)

Lars

[Darby Edelen]

Are you using color management in these projects? CS3 allows you to not only set the Working Space of the project, but also embed a color profile into the output (provided it supports color profiles, most still image formats do, JPEG included).

This should maintain the look of the image across machines. Just make sure that the project is using the same working space & output profile. Also make sure that all of the footage items in the project are interpreted the same (assigning a working space allows you to assign color profiles to footage items, the default is to use an embedded profile).

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Nel Johnson]

Hi Darby, I figured it was prolly something to do with working spaces or colour profiles. I’m a little confused as to where I adjust the colour spaces though, the project is being read from a watch folder, hence I’m not able to adjust the colour settings of a project on an individual machine. Do I embed a colour profile on the machine that initiates the multi-machine render? If so how.

Many thanks, nel.

[Nel Johnson]

Hey Lars, I’m not sure what exactly the problem is. Sure, JPG seems to be the issue. Images from one particular machine in the multi-machine setup are darker across the board. TIF sequences seem just fine – we’ll probably go with TIF and batch convert back to JPG I guess.

[Darby Edelen]

I’m not very familiar with the watch folder workflow, but if there is only one project file that is loaded onto multiple computers then that should be the only place you need to change your working space. The working space is defined in the Project Settings of the project.

The output color profile is defined in the Output Module’s Color Management tab after an item is added to the render queue, so I would guess that this will need to be done by the computer that initiates the render.

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Nel Johnson]

Hey Darby, thanks for this – I’ve found the settings you mentioned, of course they’ve been there all along but I’ve never given them a second look.

This sounds like the key to fixing this, especially given that the machine that gives the dark output is also used for print-work. My guess is that there’s a funny JPG profile in effect somewhere.

Thanks again Darby, ‘you learn something everyday’

nel.

[Darby Edelen]

[nel johnson] “This sounds like the key to fixing this, especially given that the machine that gives the dark output is also used for print-work”

Definitely could be the culprit. If a color profile isn’t defined for the working space then AE uses the system’s display color profile as the working space.

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Dean Sensui]

I’m not sure how AE does its rendering, but if it depends on the graphics card then that might be contributing to the problem.

With Apple’s Color, for example, the user manual specifically states that rendering with different Macs could alter the color since the process is dependent on the graphics card. Different machines with different graphics cards will yield different results.

Thus they recommend that if multiple machines are used in rendering, that one machine be used for a specific shot, and not split up a shot among a variety of machines.

Or use several identical machines.

Dean Sensui — Imagination Media Hawaii