App appears dark on LCD projector

[Ian.W]

Hi all,

I have a weird problem report, and I'm fishing for ideas on troubleshooting.

My colleague frequent connects to client's LCD projectors and some of the time our CVI-built apps appear much darker than normal on the screen.  The darkness occurs for all colors ranging from (normally) light grey to deep blues.  When he returns to PowerPoint or other non-CVI apps, there is no darkening of the projected image.

My first thought is that it might be a color bit-depth issue, but that can't explain why other apps are not affected - unless we are using peculiar colors that are badly affected when bit depth is dropped to 16 bits.

One unusual aspect of this is that he is using a DisplayPort to VGA dongle, since his Dell Adamo XPS does not have a VGA port. (It is Windows 7, 64-bit).

Any ideas on what could be happening?

Thanks,

Ian

[srdfrn]

Hi Ian,

Just a couple of questions for you --

How often does this phenomenon occur?  Are certain controls appearing much darker than normal, or is the entire application panel displaying this behavior?  Does the application look the same on the computer screen, but darker when displayed from the projector?  Do all CVI applications exhibit this phenomenon?

One thing that might be useful for us to see would be a picture of this behavior (or a screen shot if applicable). 

Thanks!

Regards,

Stephanie R.

National Instruments

[Ian.W]

Hi Stephanie,

It is happening about 75% of client visits when he uses their LCD projector. The image is only darker on the projector, but when cloned on the PC it is okay. Screenshots are okay, so it seems to be related to the projector.  I have asked him to try out several different CVI applications and report back.  I'll let you know what I learn.

Thanks,

Ian

[Ian.W]

This issue continues to crop up occasionally for all the CVI-developed apps that my colleague uses (~4).

The interesting thing is that I saw something like it for the first time today. I launched our app within a Windows Virtual PC (XP) and initally the inactive tabs of the app were near-black. Image attached.  When I clicked on the app the darkness disappeared. It was repeatable for a while with each launch of the app only at 16 bit color depth, but then was no longer repeatable.

Perhaps this is a clue for someone more knowledgeable in how CVI renders the screens. I'm still using CVI 9.1.1(450)

--Ian

[Kyle_M]

Ian,

Does this only happen when he runs it from that computer? If so, have you tried updating the video card drivers? It could be something very weird about the video card driver that makes it handle it poorly. I have not heard of this issue happening on other machines before. 

Regards,

Kyle Mozdzyn

Applications Engineering

National Instruments