Seeing a difference that isn't there?

Continued from here: https://photography-on-the.net …p?p=10579011#po​st10579011

Very strange. I opened both images into Photoshop using the embedded profiles and there is still a slight difference, visible if I switch them left to right, top to bottom. Its similar to the difference I get between DPP and Photoshop, although possibly even more subtle.

I checked one skin colour in the same location (x/y coordinates) and get exactly the same RGB values from both. So why me and not others. Any ideas anyone?

Maybe this needs to be in a different thread Rene? It may not be fair to the OP to take this in a different direction.

Split off

If I read your post correct, you see the difference when you view the images side by side or above each othr?

Isn't that simply caused by (the viewing angle) of your screen?
Or it might be that your screens illumination isn't even.

In both cases, the difference in brightness would not be related to what image, but to what position on your screen. Easy to test.

If you want to really compare them, layer them in Photoshop, then switch on/off the top layer.

Rene,

First, thanks for splitting it away.

I've tried Elies two images every which way, and looked at them from left and right (from up and down are more difficult!) and the difference is constant.

Strange it certainly is.

You're not alone. I see a difference too even though there is none. I noticed my inability to see two identical things because of my job, which in part involves reproducing artwork digitally that was originally produced manually and having the result be identical.

I often have to ask colleagues for a second opinion because I see slight difference where there is none. If things are ever so slightly different then that stands out a mile to me, whereas others miss it but I can draw two identical black squares, print them out and hang them in the controlled light box and see one as slightly grey or slightly taller.

I went to an optician because I thought it was my eyes and they said it was normal, it's just the way your brain processes information from two eyes. Some people see it, some people don't, some people see it but ignore it without knowing.

A more accurate/easy way to tell if there are any differences is to layer them in Photoshop, but instead of switching visibility on/off, simply change the blend mode of the top layer to Difference.
If there is no difference (which there isn't) the result will be solid black.

Stevekin,

I've just done exactly as you suggested and you are right, its just a solid black. Yet when I go back to normal blending and turn the top layer on and off I can still tell, so something is carrying across. It's not random, I can tell precisely which one is which with 100% accuracy.

Hank, I've never noticed this before. I layer up and hand match my panoramas, so am fairly comfortable getting close colour matches although I use the RGB numbers to get precise.

Stevekin wrote in post #10584143
A more accurate/easy way to tell if there are any differences is to layer them in Photoshop, but instead of switching visibility on/off, simply change the blend mode of the top layer to Difference.
If there is no difference (which there isn't) the result will be solid black.

Yep. And if there's a very small difference, it will be *almost* solid black: Very, very dark gray

Rene,

Close enough to black I'd not be able to tell?

As you know, I have a DPP versus Photoshop difference that we have aired several times here, hence my digging into this in the hope it just might help me with that.

Lowner wrote in post #10589229
Close enough to black I'd not be able to tell?

Yeah.

To illustrate:

Downloaded one of the images, added a subtle curves adjustment (128 > 130). You can just see a difference.
Duplicated background layer. Top layer set to blend mode difference.
Looks "black"
Added another curves adjustment layer on top, to make the difference visible: (10 > 255)