Very strange issue with projector

michaelp

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The projector is a Panasonic PT-MZ670. Using 13" MacBook Pro Early 2015 on Monterey 12.4. Image opened in Preview app. Connection via HDMI.

Using Preview in full screen mode, the whites and highlights in the projected image are overblown and the image just looks terribly.

Curiously, when Preview is in normal view mode, the projected image is perfect.

Can anyone explain why this should occur and how we can work around it? The projector cannot be adjusted (ceiling mounted, belongs to a third party).

We usually project using a HP laptop which results in the same overblown effect.
 
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My experience with a Photo Club projector is that the projector may need a Profile created using a Calibration device that can calibrate projectors. (Spyder, ColorMunki, etc?).
In the HP laptop you would use the Profile created for the projector to achieve a possibly better result.
 

michaelp

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But can you explain why the projected image looks so very different when on the Mac it it is in Full Screen View, despite it looking exactly the same on the Mac (except slightly larger) than in Normal view?
This is really doing my head in!
 
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I understand your confusion with the differences between the views and have no immediate solutions.

I would start by ensuring your HP laptop is calibrated so you know which is the correct presentation.

Unless it is a high end projector, you will likely have issues matching the laptop. Check the gamut specs for the projector. One of my clubs were allowed to try and calibrate the ceiling mounted projector. Yes, it involved a ladder. We were not able to calibrate it’s colours properly. Likewise at another club where we had our own projector. At my current club we have our own calibrated projectors but they were expensive.

As to your question about the difference between the two viewing modes, it sounds like LrC uses as separate utility for full screen mode.
 

michaelp

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Just to be clear the images (jpg) were being viewed in Apple’s built-in Preview app on a MacBook Pro connected to the projector via HDMI. The projector was a Panasonic PT-MZ670.

Preview app has a full screen mode. It was only in that mode the projected images were overblown, although they looked perfectly ok on the Mac’s screen.

It is of course the full screen that is being sent to the projector in any case, so how the hell can the projected image quality change like this? I just can’t see how technically it would be
possingle?
 
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So for my confusion, but is this a LrC question of Apple Preview App question?
It is really a hardware/software question question and the Lounge is the right place here for that discussion.
I think the laptop needs an icc profile to use the projector as a second monitor. Get a calibration tool to create an icc profile tuned to the characteristics of the projector. Use this created icc profile in the Mac Display settings.
The ceiling mounted monitor should also have some controls to adjust the brightness, focus, keystone correction etc. Look online for the user manual for your projector.
 
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We usually project using a HP laptop which results in the same overblown effect.
Yes, it’s interesting that the same effect happens on both the MacBook Pro and the HP laptop. That would suggest it isn’t specific to the Preview app on the Mac, and it’s probably not specific to macOS or Windows.

And it might also mean it isn’t specific to calibration, if it does the same thing even though the Mac and the HP probably apply different default profiles for the projector. Although I do recommend calibration, I wouldn’t expect it to fix that big difference between normal and full screen mode. Because a profile should have the same effect on both.

What I am wondering if there is something about the projector that processes images differently for full screen mode (regardless of Mac or Windows), like some kind of automatic in-projector image quality “correction” or “enhancement” that gets applied in only one of the two modes. For example, suppose the projector assumes full levels (0–255) when showing a normal computer desktop, but assumes video levels (16-235) in full screen mode because it thinks you’re now watching a movie…maybe that could produce unwanted clipping?

But I don’t know very much about projectors, you’d have to look in the projector manual to see if that is even a thing. If the third party is unable to provide the manual, look at the model number and see if you can find a PDF version of the manual online.

If you do find the manual, another thing to check is whether the projector has different display modes. Maybe it’s on some kind of Auto mode that tries to “enhance” everything coming through, and maybe there is a button on the remote that can switch it to some kind of un-altered “native” or “passthrough” mode that would be more suitable for critical photography viewing.

If you did have the opportunity to calibrate it, I would certainly investigate which mode the projector is in during calibration. Just like TVs and computer displays, if it’s in a mode that does too much dynamic correction/enhancement all the time, it will change its behavior so frequently that a profile won’t have a fixed baseline to correct.
 

michaelp

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Thanks Conrad Chavez - that's given me a few leads to work on, and I've just located the very long manual. Nothing obvious as yet, but I'll delve further.

Meanwhile I've attached screenshots to show example source images.

The projected full screen version would have all the whites and highlights completely blown out; but in the non-full screen view, the projected image looks OK (which is of course the whole screen - Preview window, menu bar, desktop etc.)

Since the feed to the projector (Panasonic PT-MZ670) is just video via HDMI of the whole screen in either case I'm at a complete loss to understand how the difference occurs.
 

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RoyReed

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One thing you could try: turn off the Dynamic Contrast setting (under Picture menu)

"Light adjustment of the light source and signal compensation are performed automatically according to the image to make the contrast optimum for the image."
 
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