Is this what you mean by laser speckle

[Martin McCaffery]

Was on vacation in the DC area and saw A Complete Unknown at the Regal Springfield Town Center. Opening day, 69 seat theatre, last minute decision, so ended up sitting in the second row (I never sit that close).
There was a stupendous hot spot in the lower audience right section of the screen. Whenever the hot spot included a bright white or high contrast Image, that area looked like the picture was breaking up. Rest of the screen looked ok.
From what I could see, the screen must have had micro-prefs, on none at all.
Don't know what the picture looked like from the back of the house.
Do not know if they use laser projection, but I have never seen this effect anywhere else, and I've not seen laser projection anywhere, either.

Whatever it was, it should not be on the screen. And if it is an inescapable by product of lasers, looks like laser presentations should be skipped.

[Steve Guttag]

Speckle is going to show itself as either green or red and possibly both...it is up to you. Within the solid color, it will appear "noisy." I will not be located to a part of the screen unless the screen is damaged in some manner to enhance the conditions that results in observed speckle (like it might be glossy/directional). Generally, higher gain screens have observed speckle more than matte screens. If you Google "speckle (interference), you'll get a picture of what it can look like in an extreme sense.

[Carsten Kurz]

Speckle looks like sparkle or glitter, not like what you described. You will notice it over the full screen, usually in bright primary colors or white.

[Martin McCaffery]

OK, did not see it all over the screen and not in a single color. The best I can describe it, a week later, is that it looked like that section of screen was made of etched glass.
I've seen similar effects while having a migraine headache, but was not having one at the time.
Anyone else seen anything like this?

[Ryan Gallagher]

Just curious, were you center row or off to one side?

[Martin McCaffery]

2nd row, third seat from the right.

[Ryan Gallagher]

2nd row, third seat from the right.

Haha, maybe it was a silly question... in a 69 seat theatre the rows had to be what, 7 to 10 seats each? 3rd from the right is almost center. LOL

I would have been curious if your observed defects moved with your viewing position or not... basically part of a high-gain source hotspotting or something more mysterious.

[Martin McCaffery]

Alas, I didn't get to move around the theatre. And I didn't watch the movie in the fully reclined position that the rest of the row seemed to enjoy.

[Ryan Gallagher]

The youtube algorithm gods plopped this in my feed today, nice. Perhaps best primer I've seen on laser speckle (the physics of it). A lot of his other content looks technically just as interesting.

[Ryan Gallagher]

Hands down the best explainer (with visuals) I've seen for laser speckle. Huygen Optics has some really fascinating YT videos, and this was simply uploaded as YT Short. LOL.

It doesn't "quite" get to how a screen itself can also contribute to speckle, but the basic optical concepts are there. Being a diffuse reflection surface, presumably the same concepts apply in building up the interference patterns on it's way to your eye.

https://www.youtube.com/shorts/y5yk4JWY1Zw

[Leo Enticknap]

A humongous hot spot is usually caused either by poor triaxial alignment of a xenon lamp in relation to its mirror (X/Y/Z - up/down, left/right, and backwards/forwards) or, more rarely, damage to one of the optical components of a lamp-based optical path. I can't recall ever having seen one produced by a laser-illuminated projector.

[Ryan Gallagher]

Bumping.

I was at Regal Westgate in Austin Texas today (Auditorium 10) for one of their "standard" 4K laser shows (2026 Spider-man).

I have not been in a theatre other than my own in eons, and not around many laser 4K screens. Overall it was a decent presentation... but boy howdy am I one of those people susceptible to really noticing laser speckle, and they had it pretty bad... if you get sucked into the movie you can mostly ignore it... but if you are actively analyzing picture it jumps out and says "here I am". Like it's so pronounced that it overules textures of things you should be seeing in 4K like wood grains that are slightly distant from the camera etc. It is definitely best described as full field color "noise/grain/static"... and if you are sensitive to it you can see it even in skin tones and colors way below those bright solid color fields.

Screen gain was presumably above well 1.0, because I was off to one side and there was a definite off axis general hotspotting due to the incident angle.

Otherwise pretty good.

The other things I would ding them for is volume, definitely played below well below 7.0 to my ear. Did not have that big action movie sound. But it was also a 2:30 weekday screening, so they may be in the habit of turning those down a touch.

About 20 min of trailers/ads after advertised start time, and there were some aspect ratio shenanigans within those... I saw at least one scope film trailer played as the flat DCP version despite the masking being pre-set for the scope feature, maybe that was the only version they had. No masking moves between preshow and feature, but some of the preshow filled the constant height scope screen so I'll give that a pass.

In pre-roll/trailers, everything other than the actual scope ones revealed a slight keystone that was un-compensated and un-cropped.d

Edit: I can also understand the OP's comment about looking like "etched glass". I used to work in lithography with etched and diffusion glass products... it is a reasonable alternative way to describe it. Not so much that the image is being viewed "through" etched glass, but that the surface of the screen feels like it could be made of such diffusion glass when speckle is pronounced.