Transparent blocks visually use the brighter light level that they are next to

Well there is a tiny difference in brightness on these images. Just open them in different tabs in your browser and switch between them and you should see it.

I could reproduce the same thing with redstone dust, stone pressure plates, and so on. Might be either because of some rendering glitch with transparent blocks or because they are slightly darker than the background and the game applies some contrast/hdr filter to the rendered image.

Again a contrast enhanced diff - in fact, there is a little difference around the flower pot.
If this little difference is emitted light of the pot or diffrences in rendering is unclear

After playing around with this a bit (turning smooth lighting off makes the problem more visible), it seems to me, that transparent blocks are picking their visual brightness from either the block above them or one of the 4 block beside them and they use the maximum brightness from these blocks.

I'm not really sure why they do that, but that's clearly the source of the problem. It could problaby fixed by just using the brightness of the block itself or if that's not possible for whatever reason, just substract 1 from the previously calculated maximum brightness to compensate for the added distance from the lighting source.

On a side note, this also explains why half slabs on the ceiling are often rendered too black. The algorithm doesn't take the brightness of the block below into account, so that should probably be fixed, too.

Daedalus Young, to confirm that it's not an eye trick, you can cover the pot with your fingers and alternate the tabs where the images are opened, just as Jonathan Haas suggested. If you don't see the pot but you see the small difference in the light, there's no eye trick caused by contrast.

Applies to all transparent blocks.

Now that it was renamed I see that MC-2729 is the same issue.

Note that the summary isn't completely correct. If the light source is below the transparent block , the brightness of the transparent block is usually one light level below the light level it's supposed to be.

I added some screenshots to make this problem more visible. They are made with smooth lighting off in an enclosed cube of iron blocks.

Is this still a concern in the current Minecraft version 1.6.4 / Launcher version 1.2.5 ? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Still in 13w39b.

The "fix" isn't any better - now they are one darker than the brightest neighboring block, even tall grass in direct sunlight!

That was reported in MC-45492

This bug happens AGAIN in 14w05b, after the "transparent blocks are much darker" bug was "fixed"...

Reopened (Probably MC-45492 was fixed by reverting the fix of this issue)

I think this bug is not explained correctly. The problem is that transparent blocks visually use the brighter light level that they are NEXT to.

Example pictures:

https://dl.dropboxusercontent.com/u/12694594/errror.png

https://dl.dropboxusercontent.com/u/12694594/error2.png

No issue found in 14w34b. Probably fixed when MC-92 was

The issue does exist in 14w34c, it was never fixed. The error occurs within gradients of light, never in total darkness, as Bad Time above mentioned. This should probably be in the description...

Attached @unknown's screenshots to this ticket and updated the description.

Ah yes. Difficult to reproduce but finally did see it. Just a visual bug though. Does not affect the lighting level.

Confirmed in 1.8.

Confirmed for 1.8.1-pre2.

Confirmed for 1.8.1-pre3, becomes extremely problematic as seen in attached screenshot (with tall grass).

Still in 1.8.1.

Confirmed all the way up to 1.8.2-pre6.