Ed Applying luma curve to photos and footage

[JayUtah]

Come on orphia. Read my 6 replies to each photo.

We have, and we have further explained why your answers do not satisfy. First, the purpose of the exercise was to test the accuracy of your method of manipulating the luminance channel as a means of detecting forgery. You used it only in a couple of instances, and your interpretation of the results was problematic. Second, you equivocated on all six. If your ability to confidently detect tampering vanishes in a controlled, blinded test, this is a red flag. Your own validation protocol did not use images in which it was possible to know by other means whether tampering had occurred. Your reluctance to demonstrate your method and skill when someone else knows the right answers belies to skeptics that you aren't sincere.

 

[JayUtah]

Jay found halos in one of the pictures you looked at.

Two, actually. But then again, I only looked at two using @nt1's method.

This is the enlargement of the Cleveland mill scene as posted by @nt1. View attachment 61675 Notice how the figures acquire halos proportional to their distance from the viewer. Those in the far distance, at the top of the image, are fully obscured by their halos. This is consistent with the effect being the result of how much the edge of the feature is composed of the midtones that the luminance map has amplified. It's remarkable that @nt1 did not notice the halos in his own application of the method, and instead said he believed this image was unaltered.

Here is the one I produced using @nt1's method. He applied it to the entire image and failed to observe halos. I applied it to an (oversampled) enlargement of the tree detail and was able to obtain halos.

View attachment 61685

This is evidence in favor of the proposition that the effect correlates to the degree of oversampling. Many of @nt1's 9/11 images are oversampled because they are enlarged details from larger images.

 

[JayUtah]

What about this version?

Or mine?



It's obviously composited—badly. Now I apply @nt1's method using his preferred tool...


No halo around the obviously composited element. But you do see the white borders on certain features inside the composited element: the visor boundary, some elements of the bumper car. These are on the interior of the feature, parts that are not (and would not be) affected by the alpa channel during compositing. Those are all α=1 parts of the image. They are, however, edges that would be detected by a crude band-pass filter because they are the transition pixels between areas of high luminosity and areas of low luminosity, all unconnected to the composition boundary. They are predictably absent in the edges around the Stig's helmet because the transition between his white helmet and the white background employ transition pixels that fall outside the passed band. They are both high-luminosity areas, so the passed band is on the right side of the curve—the highly attenuated and highly differentiated part of the luminance map.

 

[Thermal]

View attachment 61766
I hope this doesn't trigger the group.
View attachment 61767
Idk. It might be real footage...

Has anyone downloaded a photo app and tried to apply a curve and examine it. That would be helpful.

Yes, JayUtah has done so and provided multiple examples.

I have not done so myself (as many others have not) because the Photo Curves app itself says it will not reveal masking lines, and we see it is your misunderstanding of what it is doing that creates your artifacts. There is no benefit to spending time recreating what we all know is an error.

Eta: JayUtah has done so because he puts in the above-and-beyond-the-call-of-duty time and effort to be exceptionally meticulous and thorough, leaving no room for doubt, and he shows his work.

Kudos to him, much appreciated.

 

[Thermal]

PSA for those following this ...ahem... lunacy: let us have a moment of silence (or snickering) for the no longer among us nt1. After lobbying to get this thread a more respectable title, he took his own membership via suicide by mod, and will not be missed.

 

[P.J. Denyer]

PSA for those following this ...ahem... lunacy: let us have a moment of silence (or snickering) for the no longer among us nt1. After lobbying to get this thread a more respectable title, he took his own membership via suicide by mod, and will not be missed.

I thought it was just a two day cool off? Which I thought was pretty lenient considering the posts in AAH.

 

[Thermal]

I thought it was just a two day cool off? Which I thought was pretty lenient considering the posts in AAH.

It was followed up a few hours later with "upon more sober reflection, why bother with formalities?"

 

[P.J. Denyer]

It was followed up a few hours later with "upon more sober reflection, why bother with formalities?"

You look away for two seconds...

Well, it ended as I expected, just a little sooner than usual. Doubtless the mods will be fending off several sock puppet attempts for a while.

 

[Thermal]

You look away for two seconds...

Well, it ended as I expected, just a little sooner than usual. Doubtless the mods will be fending off several sock puppet attempts for a while.

I like to think that he found himself so slick and brilliant that he already had a sock set up, and is watching us as we post. Presumably with a halo around his head. Or something.

 

[P.J. Denyer]

I like to think that he found himself so slick and brilliant that he already had a sock set up, and is watching us as we post. Presumably with a halo around his head. Or something.

Presumably, if you run the text of our responses through the right filters, squint, stand on one leg, tilt your head to one side and cover your right eye, you'll see a sguiggle that looks a bit like "nt1 is right about everything" After sixteen pints.

 

[Thermal]

Presumably, if you run the text of our responses through the right filters, squint, stand on one leg, tilt your head to one side and cover your right eye, you'll see a sguiggle that looks a bit like "nt1 is right about everything" After sixteen pints.

I'll drink to that, although after the cognitive assault in this thread I was quite preparing to anyway.

 

[sackett]

So that was the end n of Enty Wun D'Nooby.

But what's JAYWYOMING? I never voted for that!

 

[JayUtah]

So that was the end n of Enty Wun D'Nooby.

But what's JAYWYOMING? I never voted for that!

Give me 90 minutes and a clear highway and I can make it happen.

 

[P.J. Denyer]

Give me 90 minutes and a clear highway and I can make it happen.

How about 'JayIdaho'?

 

[Thermal]

Surely he'd prefer to photoshop himself into JayMaldives?

 

[JayUtah]

How about 'JayIdaho'?

Thank you, no. I’m not a fan of being in Idaho.

Surely he'd prefer to photoshop himself into JayMaldives?

Go on…

 

[P.J. Denyer]

Surely he'd prefer to photoshop himself into JayMaldives?

Yes but nt1 didn't "hilariously" call him that.

 

[JimOfAllTrades]

Give me 90 minutes and a clear highway and I can make it happen.

But then you're in Evanston and that's just... not right.

 

[JayUtah]

But then you're in Evanston and that's just... not right.

If you want to buy alcohol from something other than the limited state-run stores in Utah, from my house you have a choice between Evanston, Wyoming or Wendover, Nevada. Neither city has much else to recommend it.

 

[Dave Rogers]

If you want to buy alcohol from something other than the limited state-run stores in Utah, from my house you have a choice between Evanston, Wyoming or Wendover, Nevada. Neither city has much else to recommend it.

So if you ever go teetotal, will that be two posts for the "Places you'll never go back to" thread?

Dave