Overly saturated colors in Windows VM on Dell UP2715K

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MihaiE

Member
So, I went crazy and bought a Dell UP2715K - that's a 5K monitor. Colors in OSX are OK, however colors in Windows VMs (Windows 10) are overly saturated. When I say overly, I mean it's an unbearable 2x increase in staturation. The red "x" window close button (i.e. when you hover the mouse over the "x" close button) is super-bright red.

I initially had a 4K monitor i.e. Dell P2415Q, and everything looked as expected (i.e. as they look on my Macbook Pro Retina). On this monitor, colors in Windows VM (and only there) are completely crazy.

I would appreciate an insight on how to fix this...

Here's how it looks (a screenshot with Windows Explorer, pay attention to the red close button and to the blue "free space" bars):

UP2715K.png

And here's how it should look:

Normal.png
 
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What I have tried so far:
- increase the video memory: I normally use 512MB, so I tried 1GB, then even 2GB - no change
- reinstall Parallels Tools - no change
- even tried to force (in the Windows VM) a color profile from a driver for this monitor from Dell's website - no change
- tried to disable DirectX, acceleration - no change
- tried both retina & scaled, the same results
 
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Very odd: I have replaced UP2715K with the previous P2415Q and now, when looking at the above to images, I can hardy see a difference myself. As said, very odd, since on UP2715K the differences are huge.

I will return the UP2715K. I leave it up to Parallels staff as to whether to pursue this further or not. I will be no longer interested in this issue. Thank you.
 
I have studied the problem in more detail and, after careful consideration, I think Parallels should fix it though. Because it seems to be a bug (or something not implemented yet) in Parallels. Let me explain:

1. Dell UP2715K is a "wide gamut" monitor. I began to believe it may not be its fault when I noticed that the above two screenshots are almost identical (with a slight difference only in red color for the close button) when displayed on Dell P2415Q or on the MBPr - however, the same two images displayed on the UP2715K show *huge* differences i.e. in the first image the "close button" red is a very bright red, while the "space left" blue is more towards cyan (I suspect these huge differences can only be viewed on Dell UP2715K!). The second image looks like on P2415Q and MBPr. So, my conclusion is that the first image contains some color information which UP2715K reproduces in one way and the other two reproduce differently.

2. In OS X, colors are as expected (the monitor is set to the "CAL1" color profile, since the other profiles do not look right). The monitor was properly recognized and the color profile is automatically selected as "Dell UP2715K". Color translation I guess does the job of keeping everything in control.

3. In Windows VMs, colors are awfully oversaturated. I suspect Parallels does some under-the-hood color profile translation based on something, and in this case that translation is probably missing because of an "unknown" monitor. As a result, color translation goes crazy or does not happen at all. This is where Parallels should step in and fill the hole by using the same color profile / color translation table as OS X for UP2715K.

4. As a last piece of information, I usually do backups with Clonezilla. That's a Linux-based environment, booted from USB. So, when booted on UP2715K, the red color that's used is the same bright red. I suspect that the Clonzezill environment is also missing a color profile for UP2715K (or does us a generic color profile for everything, and UP2715K does not behave as standard monitors do i.e. a "generic" color profile does not serve it well). This detail is only thrown in to demonstrate that in the case of UP2715K, a correct color profile is mandatory.

Thank you!
 
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Hi MihaiE, the virtual machine is not able to draw anything using native pixels/coordinates, only in logical coordinates.
Mac OS logic will always scale the drawn pixels by Windows from logical to native coordinates (hence the bad resolution) and this can not be bypassed.

When you are using Retina on 5k-display Mac. In this case the logical resolution will be 3008x1692 in Windows. It will be almost 3/4 of native Mac resolution. And this issue is related to Mac infrastructure, not the virtualization part.
 
Paul - does this reply refer to my question? Because I didn't ask about resolutions (scaled or not) but about colors and color profile.
 
I know maybe this has already been answered, but on fullscreen there is a tick in configuration of the VM that says "allow windows to set gamma". The colors you show in the screenshots actually look like very overexposed gamma.
 
AlekseyM said:
I know maybe this has already been answered, but on fullscreen there is a tick in configuration of the VM that says "allow windows to set gamma". The colors you show in the screenshots actually look like very overexposed gamma.
Click to expand...

Thank you Aleksey for your reply. I have RMA'd the monitor and I am currently waiting for a new one (the same model) since it had a cosmetic issue as well. As a result, I cannot test this, but I will. However, the colors were the same even for VMs that were not in full screen mode. Would this apply to them as well, because as per the category, it seems it would not?
 
I've had the gamma change even in windowed mode. So I'd try it either way.
On a sidenote, do you have any color issues with the monitor in Mac as well? I've always had these weird artifacts with it (hard to explain, but dark colors dither in groups..)
 
AlekseyM said:
I've had the gamma change even in windowed mode. So I'd try it either way.
On a sidenote, do you have any color issues with the monitor in Mac as well? I've always had these weird artifacts with it (hard to explain, but dark colors dither in groups..)
Click to expand...

Alexey - so you have an UP2715K?

Setting UP2715K to one of the pre-calibrated settings (CAL1 or CAL2) made everything look right. Colors were a little more vivid than the P2415Q, but I wasn't sure whether or not those were the real colors actually. Plus it wasn't such a night-and-day difference as it was in Windows VMs, but more of something like "is this a little more intense, or is it just me" - so, not very obvious. It might be also something related to the very aggressive anti-glare coating that P2415Q (and matte monitors in general) do have, plus I could not find a reasonable gray (on P2415Q I mean) until dialing down R and G channels by 3% in monitor OSD menu. Now, when I'm back on P2415Q, I have the impression (in OSX) that colors are a little on the dull side.
 
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I did, but stopped working with it on my mac pro. It didn't work really well, I had the weird color issues like I described. Even at 60hz it felt delayed and the iMac still felt faster. I suspect it's something to do with color profiling and the speed with mac's custom timing controller. I think the Dell was definitely designed for Windows and a gtx 980 I had drove it really nicely (now that I think about it, no speed issues). In the long run, I returned it anyway within my 14 days. I am not a video editor, or photo editor and primarily a developer across all platforms (thus my need for parallels). I wanted/needed something that would make fonts look incredible nice since the iMac is still way too glossy and something that high enough of a rez so that I could see an iPad w/o scaling.

All in all, kick butt monitor, but mac has some weird issues with coloring. Do try the gamma thing though. I've had other color issues with other monitors that the gamma thing fixed (mostly saturation being too high or too low). If you use default profile in mac, you won't notice a difference. If you don't, the checkbox will make a difference.
 
Yesterday I have tested Philips' 5K display, i.e. the 275P4. While I had trouble having it recognized as MST (i.e. could not make it work as a 5K monitor, only 4K), the same color issues were noticeable in Windows running under Parallels Desktop. What's more interesting, the same PNG image (comprising some orange color in that case) displayed differently (and when I say that, with a HUGE margin) while in Windows versus in the host (OSX).
So, my conclusion is that Parallels must have an issue with the color profile for their simulated graphics adapter when running on systems with displays capable of reproducing a high color gamut (both the UP2715K and 275P4 are of that kind). I would be curious to hear an iMac 5K Retina (latest model) owner's impressions on this issue.
 
Mihai,
Normally Parallels does no color correction and doesn't install color profile in Windows. Virtual display in Windows does not reflect host display identity. This should explain why VM looks different on different displays.
Contrast that to OS X with its ColorSync always on. If you take a screenshot in Windows then open it in Preview and drag from display to display it will likely look the same.
For the sake of experiment try disabling 3D acceleration for your VM. This will force Parallels to use CoreGraphics, which should be color corrected. Drag the VM between displays, is it better?
As Alexey pointed out, a full screen Windows VM in Parallels can control display gamma. This doesn't automatically solve color correction problem, but can be used to tune colors in Windows without re-calibrating display itself.
 
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Thank you for your reply! Unfortunately I have already returned the display, so I cannot test any further. However, please take into account that I was able to observe the same (identical) behavior on two 5K displays from two different manufacturers (Dell UP2715K and Philips 275P4), both displays being of the new high color gamut type.

I strongly advise you order one (you may return it after testing) and run a batch of tests. It is very strange this issue only appears on these kinds of monitors and not on regular ones. I expect 5K to be more and more of an option so at some point you will have to address this issue nonetheless.

I am a developer myself and according to what I have seen it looks like an issue with Parallels - if not something you do, then something you don't do (i.e. even if you don't provide color correction for regular situations, these new monitors may require it).
 
Well, on a second thought, I have called the courier and canceled the return. I may be able to get back to you with details within the next 48h.
 
Please see below how the same image looks like in a windowed Windows guest and, side-by-side, in OSX (the correct colors are those displayed in OSX):20160708-4S6A0005.jpg

The behavior is identical for Dell UP2715K and Philips Brilliance 275P4V
 
I can see that Windows Photo Viewer image is more vivid than in OS X Preview.
- Does that PNG have an embedded color profile? What if you strip it off?
- Do you have custom ICC profiles installed in Windows or in OS X?
- What if you disable 3D acceleration for Windows VM?
- If you take a screen shot in Windows how will it look in OS X Preview?

It may be better to start with an image made specifically for color calibration, like this one http://www.lagom.nl/lcd-test/gamma_calibration.php.
 
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This is *not* an issue with image viewer apps etc such that we could discuss embedded color profiles. The same aggresive color shift happens with standard Windows UI elements - the "hovered upon" version of the red top-right X button i.e. "close" for any window, then, application icons, progress bars, literally anything that has red or green above certain values.

Custom ICC profiles - I haven't installed/customized anything like that, all is OS-provided.

A screenshot taken of a Windows VM looks exactly the same when previewed in OSX - that is, with shifted colors.

The monitor is packed for return, it's at the office, unfortunately I have no more access to it. However, you have enough (and conclusive) evidence that it's a real issue. Please set up the corresponding testing environment, you will be able to reproduce it!

Thank you for your help so far and, if possible, please be so kind and post progress here.
 
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