Multiplying image value by -1 in node editor not working in 2.74a

Unless I am missing something here, I don’t think multiplying by -1 with the math node is working for me in blender 2.74a. I expect the pixels’ value to be the same except for the sign if I multiply by -1. However, this is not what I get. For example, when I sampled the color of a pixel close to a value of 1 and then multiply by -1 I get -14. However, when I do the exact same thing in blender 2.63 I get the expected result.

multiply_prob.blend (508 KB)

Can anyone try this out for me on your computer?

Here is my rig:

CPU: Intel® Core™ i7-4770K @ 3.50GHz
RAM: 8gb
GFX: nVidia Geforce GTX 780 Ti
OS: Windows 8 64 bit
Drivers: 347.25
Blender: 2.74a

Works fine here. Are you sure you are: a) sampling the same pixel, and b) looking at the linear output values, not the color-managed ones?

2.63 was before OCIO, back when linear workflow only sorta-barely worked properly. Judging from that and the -14 value, I’m going to guess you’re looking at a display-space value when you wanted linear?

Yes, you are exactly right. It’s a color management problem. When I change Scene>Color Management>View to Raw it behaves as expected. Thank you so much for the help. I would have been banging my head against the wall for some time before figuring that one out (if I ever did) haha