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As part of a scene I have a white diffuse surface with some black icons on it. Right below it I have the same icons in white on a black surface.

I use the same texture for both surfaces, with a node set up like this:
Node netup

As a minimal example I have a texture containing the letter A. I have it applied to two surfaces like this:
Large render

However, when the camera is further away (or it is rendered at a super low resolution) The white A looks significantly thicker than the black one:
Low res render

When rendered at a higher resolution and scaled down the results are as expected:
Scaled large render

The difference between the white and the black A's becomes even greater the smaller it is on the rendered image. Top is rensered at a higher resolution and scaled down, bottom is rendered at low resolution:
Super low res comparison

Currently the only way I can think of working around this issue is rendering at a higher resolution and scaling down the final image. This is fine for this example, but for the scene I'm working on render times are already high and I really don't want to increase the resolution.

Is there any way I can fix this and have both render at an equal thickness? Is it just a product of how the Cycles works? Is there a setting that can compensate for it? Or am I doing something completely wrong? The only possibly related question I found was this unanswered one here.

Here is the .blend file for this example:

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I'm probably going to get laughed into next week for this one.......but I think it's an optical illusion. Not only that but I think it also has to do with 3d world as opposed to 2d screen. A white A on a black background is always going to look bigger than a black A on a white background. Take the Olympic rings for example ......there is an actual formula for how thick each ring should be so that they all look the same thickness. The greatest example of this that I have ever seen is as you look up towards the alter in St. Peter's in the Vatican where Bernini makes the letters at the top of the columns larger than the ones at the bottom of each pillar as you look up the nave so that they all look the same hight from ground level. Anyway put a cube or a plane in the scene and measure it.

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  • $\begingroup$ This could certainly account for part of the difference, but there is still a difference in cycles. See the following image. Top is rendered at a higher resolution scaled down, bottom is rendered at a lower resolution. image $\endgroup$ – user123456 Apr 22 '18 at 17:19
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    $\begingroup$ @user123456 All you have to do is get photoshop and over lay the two images and use difference mode and see if they images really does have any difference in their placement by the pixel. It's an optical illusion by my graphics knowledge of how images can trick the eye. $\endgroup$ – hawkenfox Apr 22 '18 at 17:53
  • $\begingroup$ You can compare them in blender. Use the compositor feed both images on a color mix node and use difference mode. $\endgroup$ – cegaton Apr 22 '18 at 18:05

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