01-20-2011, 08:56 AM

I am in the Audio Visual business and we have problems with images with Apple laptops in projector presentations. I have tried mini DVI to DVI, Mini DVI to VGA without success. We have tried new cables/adapters to no avail.
Images that look great on the laptop screen are too dark through the projector.
The screen brighten feature has no effect on the images being projected. The laptops detect the projectors and the resolution is correct. brightness/contrast/gamma/ white settings are correct. When I immediately plug into a PC the image is perfect!

Have found little info on this issue in forums, and I am sure Apple must be aware of this issue. It is an Apple issue not a projector, adapter or cable.
Would like to resolve as I tell customers their presentations will look better with a PC to their dismay.

Advice appreciated!

Randy
RAAV, LLC.
Audio Visual Orlando

01-20-2011, 01:48 PM

Welcome to the Mac Forums.

Attaching a projector to your Mac for all practical purposes is the same as attaching an external monitor. You didn't mention which Mac notebook computer you're using, but generally they all operate pretty much the same with the exception of available resolution and output port type.

When you attach the projector, does the Mac detect it correctly? You mentioned you were using the correct native resolution - most projectors I've used are designed for 1028 x 768 or 800 x 600, with varying refresh rates. Do you have the projector setup as "mirror" mode on your Mac?

In my experience using both PC and Mac notebooks for presenting a PowerPoint display, there is no difference in brightness or contrast. Usually, the Mac does a better job. Of course it all depends on the type of projector you're using.

01-20-2011, 04:13 PM

I finally discovered the solution. You would think it being Apple they would have an intuitive solution. I mean all PCs work with with very minor adjustments.

A couple of issues.
1St. be sure to update the OS to the most current, newest as of 1/20/11 10.6.6. There appeared to be an issue with 10.4.4.

Next follow the following instructions exactly: this is RE POST


I don't have the same problem (i.e. videos too dark) but I'll bet it's the same solution. My problem was that the Keynote presentation on the LCD were way too dark. Funny thing was that if I opened up the systems preferences dialog box, they looked fine. Hummm.

Turns out that it was an issue with a change in the latest OS and how apple now handles the gamma setting in external displays. I don't recall all the details but Snow Leopard seems to use the new standard gamma of 2.2, making output too dark. The output gamma should be closer to 1.8.

To fix this, you need to adjust the color profile for the LCD projector that you are using.

To fix a projector, the projector must be plugged in and turned on to do this.

If you go to System Preferences, Displays and the Color option. You'll see a list of Display Profiles. There will be a dialog box on both the computer screen and the projector screen. To get them both on the computer screen to make editing a little easier you can click Gather Windows at the bottom of the dialog box on the computer.

I found it easier to just Calibrate the monitor and same a new profile - you can also uncheck the Show profiles for this display only and pick another profile like one of the sRGB profiles. To calibrate, click the Calibrate button (be sure you do it on the dialog for the LCD projector) I'd click Expert Mode - this will give you more options when adjusting the Gamma. Run through the Calibration routine making sure that you select a Gamma that is closer to 1.8 instead of the 2.2.

At the end, same the profile and then everything on the external display should look much better.

When researching my issue, there seemed to be consensus that using a digital interface the projector was better than the normal VGA cable. Didn't have a cable to try that.

Once you do this, the machine should always recognize the projector and behave properly. Seems a pain to have to do this but I didn't find any other alternative. The good thing is that I have not had to do this on every projector that I use. I have my own projector that has always worked properly.

I teach at a university where the rooms have mounted projectors - some work with no change, others I have to calibrate...

Try it out, hope it helps...

01-20-2011, 08:16 PM

Thanks for posting back. Glad you found the solution.