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by dbolt on Thu Mar 26, 2020 3:48 pm
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I want to use an X-rite i1Display to color calibrate a PC that controls a digital projector in a medium-sized auditorium. The images are washed out, and the colors are way off. To calibrate the PC, the colorimeter must be near the screen and connected via USB to the PC. The problem is the PC is in the control room, which is nearly 200 ft from the screen. Much longer than the specs for USB cables.  

An HDMI cable runs from the stage through a switch in the control room to the digital projector. The cable allows speakers to show images and videos using the HDMI output from their laptops. Color calibrated laptops project images with the expected luminosity and colors.  

My initial plan was to use an USB to HDMI adapter to connect the USB cable from the colorimeter to the HDMI cable. Then, in the control room, patch the HDMI cable into an HDMI port on the PC. Nope, PC does not have an HDMI port. 

The next plan was to use two USB to HDMI adapters, one to connect the USB output from the colorimeter to the HDMI cable. Then, with the second adapter, connect HDMI to a USB port on the PC. But, I learned that specs say the USB to HDMI adapter only converts USB to HDMI, not the other way. Management would not agree to test that spec.

The option on which I would appreciate your comments and suggestions is to use USB over Ethernet with Cat5 a cable. Specs on the solution I found on Amazon quotes 328 Ft ( Amazon solution  ). The price of the adapters seems fair, and Cat 5 cable is available.

doug bolt
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by Mark L on Thu Mar 26, 2020 5:18 pm
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I think that all you need to do is to calibrate the computer that is in the control room. You would then be in the same situation as you describe for the color calibrated laptops that connect to the projector? The projector apparently is capable of and calibrated correctly if connected to a calibrated source.
 

by dbolt on Thu Mar 26, 2020 7:43 pm
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Mark,

The first thing I did when management let me in the control room and after they switched the PC to Admin rights was to calibrate the PC for it's attached monitor. I was surprised that i1Display made very subtle adjustments. However, the OS will use a different ICC profile for the monitor and the digital projector, even without calibration. By calibrating, i1Display creates a new ICC profile containing adjustments in RGB values, etc. to make the display (monitor or projector) with correct colors.
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by Mark L on Thu Mar 26, 2020 7:53 pm
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dbolt wrote:Mark,

The first thing I did when management let me in the control room and after they switched the PC to Admin rights was to calibrate the PC for it's attached monitor.  I was surprised that i1Display made very subtle adjustments.  However, the OS will use a different ICC profile for the monitor and the digital projector, even without calibration. By calibrating, i1Display creates a new ICC profile containing adjustments in RGB values, etc. to make the display (monitor or projector) with correct colors.
In that case why do the laptops connected to the system work correctly?  Do the laptops only have a single ICC profile for all display modes?  I have never run into your situation and was just responding to the information you provided combined with my prior experience.
 

by dbolt on Thu Mar 26, 2020 8:18 pm
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The i1Display software creates a different ICC profile based on a LUT (lookup table) that the calibrated laptop uses to drive the projector. Most laptops (in my experience) do not display accurate colors on digital projectors unless the laptop is calibrated.
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by signgrap on Thu Mar 26, 2020 9:08 pm
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dbolt wrote:The i1Display software creates a different ICC profile based on a LUT (lookup table) that the calibrated laptop uses to drive the projector.  Most laptops (in my experience) do not display accurate colors on digital projectors unless the laptop is calibrated.
[font=Verdana, sans-serif]I would agree you should calibrate the laptop first and then calibrate the projector second.  Your degree of success will depend upon how good the GUI is in the laptop.  Many laptops do not calibrate well because the GUI is of poor quality as the vast majority are made to meet a lower price point and good GUI's are expensive.  The laptop market is very competitive.  It sounds like you are projecting in a large room.  I assume the screen is large as well.  This will make the projected image wash out because of the great magnification of the image and the distance the light has to travel to reach the screen.  [/font]In our camera club we’ve found that if we keep the image smaller and don’t try to fill the screen you get a more saturated image that has better contrast.  
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by dbolt on Fri Mar 27, 2020 10:30 am
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Dick,

I certainly agree with your assessment of the GPU in most laptops. However, I am not dissatisfied with the quality of images displayed after my MPA or a friend's Dell laptop have been calibrated with i1Display. Without calibration, the laptops also produce poor images on the big screen.

The washed out and wrong color I am attempting to correct concerns when the PC in the control room is the source.

If you are on a PC, search for Display Settings. The search will display the name of the ICC or ICM profile (the two are the same) your device is using. Pull down the list to see many profiles. The monitor or device these profiles support may be evident from the names. If your PC had happened to have been connected to a digital projector when you searched, the name of the ICC profile would be the one your computer was using to drive the projector. My goal is, with the help of the X-Rite software and colorimeter, to build an ICC profile that sends the projector modified RGB values that produce color values on the big screen that seem correct (or at least close enough). To do the calibrations process, I need to somehow connect the output of the i1Display colorimeter to the PC in the control room so the X-rite software can determine how to build a new ICC profile that will cause the projector to display colors on the big screen that look the correct.

In brief (and certainly beyond my expertise), the software sends to the projector, and thus the big screen, 118 different images with known color values (RGB). The colorimeter sends back the RGB values it detects. The software makes a lookup table to "fix" the problem. As an example, if the PC sent an image that was RGB: R255, G160, B122 values (light salmon) and the colorimeter detected 255, G150, B120, the software would determine how to modify the ICC profile so the ICC profile would send different RGB values to produce light salmon color on the big screen.

Because the screen and the PC in the control room are too far apart for a simple USB cable to connect the colorimeter to the PC, I need advice as to how to make that connection.
Douglas Bolt
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by signgrap on Fri Mar 27, 2020 1:13 pm
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Douglas is it possible to erect a temporary screen close enough to get a reading using the longest USB cable you have?  
Remember it is just the color you're interested in so things can be a bit askew in terms of distortion and the like.  I know the white balance may not be the same as the large screen but you'll be close and color accuracy will be greatly improved.  I have an Xrite color munki display and have used it to calibrate our club projector but we use it with my calibrated laptop which makes it easy to move things close enough to the screen that everything reaches easily.

You probably kown this but just in case make sure the room is a dark as possible when you calibrate so the only light falling on your puck, no matter how faint, is from the screen.  A lot of projection auditoriums have safety lighting and the such, if possible turn them off when you calibrate.
Dick Ludwig
 

by dbolt on Fri Mar 27, 2020 1:36 pm
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Dick,
The projector is mounted in the ceiling of the auditorium, so can’t get closer.

I I have debated with myself about calibration with dark room vs room lite like during a show. Seems to me to be better to calibrate under “real “ conditions. If I ever get a chance, I will do both and use the profile that delivers the best images.
Douglas Bolt
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by signgrap on Fri Mar 27, 2020 2:42 pm
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dbolt wrote:Dick,
The projector is mounted in the ceiling of the auditorium, so  can’t get closer.

I I have debated with myself about calibration with dark room vs room lite like during a show. Seems to me to be better to calibrate under “real “  conditions. If I ever get a chance, I will do both and use the profile that delivers the best images.
If you get the chance to do a test between the two let me know as it will be interesting to see which gives a more accurate color redition.
Dick Ludwig
 

by ChrisRoss on Sun Mar 29, 2020 1:07 am
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I don't see how having a laptop calibrated to it's display and the desktop computer calibrated to it's display is any different. If the desktop gives good images on its monitor then it should be no different to the laptop.

One test to try is to take a laptop that works in the auditorium out to the control room and plug it into the cable the desktop is using. If the colour is good from the laptop using the cable in the auditorium but is bad when trying to project using the control room PC cable then this would indicate a cable problem. You may have a bad cable or be exceeding the allowable length for whatever type of connection you are using.

You say the control room desktop does not have a HDMI port - possibly an old PC? What operating system? Earlier operating systems will only allow a single LUT for calibration is I recall correctly.

If the control room PC has no HDMI port, then what sort of cable is used to convey the images to the projector? you say you have a HDMI cable and a switch in the auditorium for audience laptops. Is this switching between laptop and control room PC - are you using any adapters there?

You could try moving the control room PC temporarily into the auditorium and running the calibration there using whatever adapters are needed to plug it into the switch. Then move it back. This will test the whole loop from control to projector compared to the loop from the HDMI cable the laptops are using.

You say the control room is over 200 ft from the auditorium - most cables have limitations on the length of cable you can use. Here is a guide:

https://www.cablechick.com.au/blog/cable-length-guide/
Chris Ross
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by dbolt on Sun Mar 29, 2020 10:31 am
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Chris,

The reason I started this thread was to get feedback on whether USB over Ethernet was the solution I should recommend to management for calibrating the PC that is frequently used to display images on the screen in our auditorium. A different solution may be better, but I do not want to recommend an approach that fails or required a lot of tinkering to complete. So far, most of the discussion has been on the mechanics of color calibration, with the notable exception of the cableclick.com link you provided above. Thanks for that link.

===========


ChrisRoss:I don't see how having a laptop calibrated to it's display and the desktop computer calibrated to it's display is any different. If the desktop gives good images on its monitor then it should be no different to the laptop.

============

The laptop and the PC function independently. Never at the same time. The HDMI cable from a laptop connects to a black box that connects to the projector. The PC connects to the same black box. The laptop never connects to the PC. Images displayed by a calibrated laptop are good enough. The uncalibrated PC is the issue.

========


ChrisRoss:One test to try is to take a laptop that works in the auditorium out to the control room and plug it into the cable the desktop is using. If the colour is good from the laptop using the cable in the auditorium but is bad when trying to project using the control room PC cable then this would indicate a cable problem. You may have a bad cable or be exceeding the allowable length for whatever type of connection you are using.

You say the control room desktop does not have a HDMI port - possibly an old PC? What operating system? Earlier operating systems will only allow a single LUT for calibration is I recall correctly.

=========

I don't recall the OS, but the X-rite software successfully calibrated the ICC/icm profile in the PC when the PC is connected to the its monitor. The issue is how to connect PC to the colorimeter, considering the long distance between colorimeter and PC.

In effect, the big screen and the colorimeter will be the PCs monitor when calibrating the PC for projection. I'm looking for a cable system to reliably connect the PC and the colorimeter. Remember, computers use a different ICC profile for each different monitor or display device. For example, calibrating the ICC profile that a computer uses to drive its attached monitor will not correct the colors displayed by the projector because the computer uses a different ICC profile for the projector. If the ICC profile for the projector is not correct, the image on the big screen will not be correct.

=========

ChrisRoss:If the control room PC has no HDMI port, then what sort of cable is used to convey the images to the projector? you say you have a HDMI cable and a switch in the auditorium for audience laptops. Is this switching between laptop and control room PC - are you using any adapters there?

=========

One end of the HDMI cable is near the big screen. The other is a black box in the control room that connects to the digital projector. I think it may be possible to patch into the black box, but the PC does not have an HDMI port. Specs on the USB to HDMI adapters say they will not convert HDMI to USB.

ChrisRoss:You could try moving the control room PC temporarily into the auditorium and running the calibration there using whatever adapters are needed to plug it into the switch. Then move it back. This will test the whole loop from control to projector compared to the loop from the HDMI cable the laptops are using.

-==========

The control room is an actual brick and mortar room.

ChrisRoss:You say the control room is over 200 ft from the auditorium - most cables have limitations on the length of cable you can use. Here is a guide:

https://www.cablechick.com.au/blog/cable-length-guide/
============

Yes, that fact is what I'm trying to work around. And, thanks again for the link.

doug bolt
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by Mark L on Sun Mar 29, 2020 12:08 pm
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dbolt wrote:Chris,

The reason I started this thread was to get feedback on whether USB over Ethernet was the solution I should recommend to management for calibrating the PC that is frequently used to display images on the screen in our auditorium. A different solution may be better, but I do not want to recommend an approach that fails or required a lot of tinkering to complete. So far, most of the discussion has been on the mechanics of color calibration, with the notable exception of the cableclick.com link you provided above. Thanks for that link.

===========


ChrisRoss:I don't see how having a laptop calibrated to it's display and the desktop computer calibrated to it's display is any different. If the desktop gives good images on its monitor then it should be no different to the laptop.

============

The laptop and the PC function independently. Never at the same time. The HDMI cable from a laptop connects to a black box that connects to the projector. The PC connects to the same black box. The laptop never connects to the PC. Images displayed by a calibrated laptop are good enough. The uncalibrated PC is the issue.

========


ChrisRoss:One test to try is to take a laptop that works in the auditorium out to the control room and plug it into the cable the desktop is using. If the colour is good from the laptop using the cable in the auditorium but is bad when trying to project using the control room PC cable then this would indicate a cable problem. You may have a bad cable or be exceeding the allowable length for whatever type of connection you are using.

You say the control room desktop does not have a HDMI port - possibly an old PC? What operating system? Earlier operating systems will only allow a single LUT for calibration is I recall correctly.

=========

I don't recall the OS, but the X-rite software successfully calibrated the ICC/icm profile in the PC when the PC is connected to the its monitor. The issue is how to connect PC to the colorimeter, considering the long distance between colorimeter and PC.

In effect, the big screen and the colorimeter will be the PCs monitor when calibrating the PC for projection. I'm looking for a cable system to reliably connect the PC and the colorimeter. Remember, computers use a different ICC profile for each different monitor or display device. For example, calibrating the ICC profile that a computer uses to drive its attached monitor will not correct the colors displayed by the projector because the computer uses a different ICC profile for the projector.  If the ICC profile for the projector is not correct, the image on the big screen will not be correct.

=========

ChrisRoss:If the control room PC has no HDMI port, then what sort of cable is used to convey the images to the projector? you say you have a HDMI cable and a switch in the auditorium for audience laptops. Is this switching between laptop and control room PC - are you using any adapters there?

=========

One end of the HDMI cable is near the big screen. The other is a black box in the control room that connects to the digital projector. I think it may be possible to patch into the black box, but the PC does not have an HDMI port.  Specs on the USB to HDMI adapters say they will not convert HDMI to USB.

ChrisRoss:You could try moving the control room PC temporarily into the auditorium and running the calibration there using whatever adapters are needed to plug it into the switch. Then move it back. This will test the whole loop from control to projector compared to the loop from the HDMI cable the laptops are using.

-==========

The control room is an actual brick and mortar room.

ChrisRoss:You say the control room is over 200 ft from the auditorium - most cables have limitations on the length of cable you can use. Here is a guide:

https://www.cablechick.com.au/blog/cable-length-guide/
============

Yes, that fact is what I'm trying to work around.  And, thanks again for the link.

doug bolt
I think that numerous posters are trying to understand what the root of the problem is and to help you resolve it.  The questions raised by the additional posters demonstrate that perhaps your original focused question is not addressing the root of the issue?

It seems to me that we do not understand what is going on with the PC in the control room.  If you dig into the control room PC to understand the operating system perhaps it will help you to dig into a way to be sure that the calibration of the attached monitor is/can be used for the projector.  It is also possible, as suggested above that there is an issue with the cable from the control room PC to the projector.

It is always good to "hear" what others are saying in their attempts to help out.  People are not hijacking your thread/question but rather trying to understand and help you to reach a solution.
 

by signgrap on Sun Mar 29, 2020 2:32 pm
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Doug the thread has gotten long and hard to follow so a couple of questions:
Have you been able to calibrate the monitor which is attached to the PC in the projection booth of the auditorium?  
If yes, is the calibration good enough to meet your needs?
If the first two questions are affirmative the only question that remains is how to profile the projector.  
Is this correct?
The problem then is you need to connect the i1 Display puck to the PC computer located in the projection booth which is 200ft from the screen via a USB cable.  But USB cables have a maximum reach of 25-30ft.  The problem is the i1 Display puck needs to be about 10ft from the screen in order to work properly.  So you need a way to get the projection room PC connected to a puck some 190ft away and the only available connection is a USB cable that is connected to the i1 Display puck.  
We know that a 200ft USB cable won't work as they don't exist, so what other options are there?
Dick Ludwig
 

by dbolt on Sun Mar 29, 2020 5:22 pm
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signgrap wrote:Doug the thread has gotten long and hard to follow so a couple of questions:
Have you been able to calibrate the monitor which is attached to the PC in the projection booth of the auditorium?  
If yes, is the calibration good enough to meet your needs?
If the first two questions are affirmative the only question that remains is how to profile the projector.  
Is this correct?
The problem then is you need to connect the i1 Display puck to the PC computer located in the projection booth which is 200ft from the screen via a USB cable.  But USB cables have a maximum reach of 25-30ft.  The problem is the i1 Display puck needs to be about 10ft from the screen in order to work properly.  So you need a way to get the projection room PC connected to a puck some 190ft away and the only available connection is a USB cable that is connected to the i1 Display puck.  
We know that a 200ft USB cable won't work as they don't exist, so what other options are there?
I have demonstrated that the projector is capable of displaying calibrated colors from the laptops.  And, the PC is capable of profiling its own monitor.  What I need is a reliable way to pass USB signal from the puck to the PC over a distance of about 200 ft.

 The USB output from the i1Display puck in front of the big screen must be connected to the USB port on the PC while the PC is projecting color calibration images on the big screen. 

As I have discussed, the only promising solution I've found is to use a Cat5 cable and USB over Ethernet adapters, such as the ones listed here Amazon link. Specs quote 328 ft. I'm hoping to learn from someone with experience if this method has a reasonable chance of success. If not, are there other options?
Douglas Bolt
Maryland, USA
http://dougboltphotography.com
 

by signgrap on Sun Mar 29, 2020 7:15 pm
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I have no idea if the Cat5 cable will work. If I understand the limitations of USB cable it's the distance (wire resistance, I guessing here) that's causing the problem when the USB wire gets longer than 10m. Someone with more knowledge than me about what happens when you combine Cat5 and USB needs to answer your question. Sorry I can't be of more help.
Dick Ludwig
 

by ChrisRoss on Sun Mar 29, 2020 8:19 pm
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The point I was trying to make is that I suspect the problem you are having with the projector is due to the length of the cable taking the signal from the desktop PC to the projector. You say it is 200 ft from control room to the projector and that is beyond the limit of any cables listed.

I suggested you physically remove the PC from it's location and carry it to where the laptops plug in to test if indeed it is a cable problem. That's why I'm asking about the type of cable running from control room to the projector, you say the PC has no HDMI port so you will need some sort of adapter to plug it into the switch perhaps? What is the distance limit for the type of cable in use?

Equally taking the laptop that works in the auditorium out the control room and trying to project through the same cable that the desktop PC is using is a reverse test. If the laptop works in auditorium but not in the control room it tends to indicate you are not having a calibration issue and that it is a cable issue.

My response was a bit rambling as I read back and forth and changed bits and pieces hope the above is clearer. Doing what I suggest may stop you heading off down a blind alley on the calibration front.
Chris Ross
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