New iMacs Screen Black Crush?

Tri-stan · Dec 21, 2012

First impressions seeing a 27 inch iMac in Apple store:

I managed to get on to a new 27 inch late 2012 iMac here in the Uk and was able to have a good play around on it to see how it performs. Overall it worked well, although adobe elements was laggy, slow to zoom on occasions even on a white screen "checker boarding" and to re-size its window was laggy. That machine was running a 675mx gfx and a standard 1TB HHD which was painfully slow to use. Other than that it was quite impressive apart from what I am reviewing below.

This is what I am most concerned about, it is the apparent black crush exhibited on the monitor. Now this may just may be software in OSX with its photo viewer but I did also notice that fonts in Safari were blotchy and had too much blue saturation which was strange.

So to quote my findings on this:

Below there are three images, The first a reference of the entire image "upon double clicking it can be downloaded at full size to test if need be" The second a close up of the most affected area "note it looks just like this in windows photo viewer as well" and the third a picture captured on my s3 of the iMac display using is own photo viewer as standard.

Analysis of affected area between "iMac osx photo viewer" and "u2711 win 7 os photo viewer":

The affected area on the iMac shows in the most black areas of the screen there is a loss of detail. Where there is more information on the u2711 the iMac seems to crush the blacks. So on the image showing the fan unit with the orange dot, "the lower portion of that unit which is darker" when displayed on the u2711 it shows fan supports and a radiator behind where the iMac's equivalent image shows just black.

Now I know using a camera to capture the information on the screen in the third photo will reduce the information held within the image but this is pretty much how it looked in the store. I have had problems like this before with srgb and rgb images on my wide gamut monitor but even using an srgb image held within the internet page it shows the information but just not on the iMac.

Questions:

I have got my computer set up so that srgb/rgb images all work across photoshop, downstream from chrome and windows photo viewer which all display the correct colors, is this even possible on the imac? I suppose you just can't use rgb images which is a shame.

I just don't understand this black crush problem if anybody can help?? Colour gamut can be really confusing at times!

Reference image

U2711 "same as what it looks like in windows photo viewer not a direct photo"

Late 2012 imac "what is seen in the mackintosh's photo viewer as a photo taken on my s3"

wessew · Dec 21, 2012

It appears as if the iMac screen needs to be calibrated. Not only do you see black crush but there is also faint white blooming. This would include the gray scale which needs to be set to ramp evenly from deepest black to whitest white. However, it appears resolution is equivalent.

bobright · Dec 21, 2012

maybe it's just me but I'll take a little black crush over a badly light bled panel any day

though I don't use Photoshop and have my work rely on perfect colors etc

Tri-stan · Dec 22, 2012

This is a total deal breaker if the monitor exhibits that about of black crush. I am buying this machine for mainly the screen being the number one selling point and number two being that it runs osx. I just can't believe that this is how it is ment to be out of the box, currently I have got less black crush on my Samsung S3 phone screen. Is it true that the iMac has become just a toy? I need to use this machine to actuary work on not for facebook etc.

I was not able to test the image on a decent version of photoshop. If Somebody was able to put the first image on cs6 and could tell me weather or not the same amount of black crush was apparent or not? This will be a true test because if photoshop's automatic colour settings means that it still can't display the dark grey's meaning black crush is still experienced and now, "well spotted white blooming as well" then good by iMac.

Please tell me I am wrong and this is just software?

digitalfailure · Dec 22, 2012

I've always found that iMacs have the default brightness cranked up way to high out of the box and its often adjusted even more to allow the screens to still pop under all the shop lighting. If colours are important to your workflow, you'll calibrate the screen before use in a decent environment anyway.

So get one home, calibrate it and if you don't like it then send it back under the return policy. You'll have lost nothing but a couple of days.

intz2nu · Dec 22, 2012

I am by far no photo expert or monitor expert, and I also don't really know what "Black Crush" is either. However I think I am almost positive in thinking that this is in relation to color differences from OSX and Win7. When I had first switched from a Win machine to a Mac (both a Macbook Air and a 2010 iMac 27") I immediately noticed color differences of both Operating Systems. I can't say if its the OS or the OS photo viewers but on a Mac OS a lot of things seemed a bit more on a yellow side when compared to a Win OS. I honestly thought things was completely south of being a new Mac user cause of how my everyday photos and frequently browsed sites would look on the Mac OS vs a Win OS.

That being said I installed Win7 through Bootcamp on the 2010 27" iMac and once all the Bootcamp drivers were in place and Windows was successfully installed I was gratefully happy to see that things looked to me what I would call "normal" once again when I was using Windows on my iMac. The white looked white and everything looked as it would on any Win machine. I somewhat think its something to do with the Mac OS being Win OS through Bootcamp on a Mac previews photos and websites as they normally would display when on a Win machine. I am also no expert in this either with regard to it being either the OS or the computer but I do know that Windows installed using Bootcamp on all the Macs I had didn't display images or websites with color problems. They looked and appeared as they would when on a Win machine. This is why my conclusion and guess is that its a OS issue.

Tri-stan · Dec 22, 2012

Does anybody know where reviews can be found for the 27inch screen? I don't think tft central have done one yet. I am sure if the iMac has as bad black crush as I have seen it will be easily reported on any decent review site.

steve119 · Dec 22, 2012

I'm not having any lagging problems with elements 10, think I need to calibrate though because I don't feel the colours stand out as much as the keynote made on.

Zwhaler · Dec 22, 2012

Tri-stan said:
This is a total deal breaker if the monitor exhibits that about of black crush. I am buying this machine for mainly the screen being the number one selling point and number two being that it runs osx. I just can't believe that this is how it is ment to be out of the box, currently I have got less black crush on my Samsung S3 phone screen. Is it true that the iMac has become just a toy? I need to use this machine to actuary work on not for facebook etc.

Calibrate your screen.

thekev · Dec 22, 2012

wessew said:
It appears as if the iMac screen needs to be calibrated. Not only do you see black crush but there is also faint white blooming. This would include the gray scale which needs to be set to ramp evenly from deepest black to whitest white. However, it appears resolution is equivalent.

Well evenly is a strong word there. Gamma 2.2 isn't exactly even. It doesn't have that many values allocated to deep shadows in a range normalized 2**8, so this is a strong statement. I can't think of a single display on the market that's absolutely perfect on shadows. It's quite possible to see clipping at 0-2 or 0-3 in photoshop. Typically you shouldn't have problems past that. The biggest fallacy on here is the idea that a custom profile will absolutely fix this.

A custom profile or calibration updates the output response instructions, but most of the software/colorimeter combinations have trouble with extreme shadow values, and the factory is the only place that can truly calibrate these values at a hardware level. I mean there are things that the software can do to attempt for a better 0-255, but it's quite a bit more limited than this forum wishes to admit. It sets a target. It measures. It generates a small matrix for adjustments. You can then verify with further measurements how close it came to meeting the targets, and the measured behavior is included in another part of the profile so the system knows the capabilities of the display in its calibrated (sort of) state.

I just don't want people to think this will always resolve every problem. If they're trying to determine if a display should be returned, it's best not to rely on the idea that this will fix it all later. The OP would be best off doing this within the return period to ensure it will meet his needs. Even if you get a really good display, proper measurement is optimal.

bobright said:
maybe it's just me but I'll take a little black crush over a badly light bled panel any day

though I don't use Photoshop and have my work rely on perfect colors etc

They're independent of one another. Backlight bleed has been seen in some of these.

Tri-stan · Dec 22, 2012

thekev said:
The OP would be best off doing this within the return period to ensure it will meet his needs. Even if you get a really good display, proper measurement is optimal.

Luckily this was an iMac that I was testing in the Apple store for half an hour and not one I had to wait for. To be honest if this is a screen issue or if it is a poor factory calibration I am not coming to buy Apple to be hit with serious issues. I come here for the USP that Apple claims, which is a more trouble free computing experience. If I have to calibrate a monitor I expect to do so to finally tweak the colour performance. My u2711 comes with a great base calibration but the iMac seems way off in terms of black crush and white blooming which I don't even think can be fixed with a colour calibration right. That is just for tweaking the final colour settings not for major adjustments.

So either the Apple store has got a faulty 27inch iMac on display or they are all going to be all like that, either way I am this close to calling it a day on the iMac. Professionals are better off looking elsewhere.

thekev · Dec 23, 2012

Tri-stan said:
My u2711 comes with a great base calibration but the iMac seems way off in terms of black crush and white blooming which I don't even think can be fixed with a colour calibration right. That is just for tweaking the final colour settings not for major adjustments.

So either the Apple store has got a faulty 27inch iMac on display or they are all going to be all like that, either way I am this close to calling it a day on the iMac. Professionals are better off looking elsewhere.

You're right about all of that. Some displays offer a bit more flexibility than others in this regard. Internal LUT systems help with leverage, but color, range, and uniformity have to be addressed first at the factory. Calibration grants you an individual measurement to sort of even things out along the range and test the gamut at that time for color management purposes. It doesn't fix hardware though.

James_C · Dec 23, 2012

While many professionals do use iMacs, you do realise that the iMac is Apple's consumer desktop, not their professional line.

Any professional would also know that no matter how good the factory calibration is, you would need to use professional calibration hardware and software for the ambient lighting in the room that you use it. You appear to ignore all the previous suggestions for calibrating the screen.

While Apple's displays are better that a lot of displays, if colour accuracy is that important then you would not be using an Apple display anyway, you would be using something like an Eizo.

Tri-stan · Dec 23, 2012

James Craner said:
While many professionals do use iMacs, you do realise that the iMac is Apple's consumer desktop, not their professional line.

Any professional would also know that no matter how good the factory calibration is, you would need to use professional calibration hardware and software for the ambient lighting in the room that you use it. You appear to ignore all the previous suggestions for calibrating the screen.

While Apple's displays are better that a lot of displays, if colour accuracy is that important then you would not be using an Apple display anyway, you would be using something like an Eizo.

This isn't just a problem for professional's, if any person takes a photo with a decent camera they are not going to be able to see any of the details in the black area's. This just sounds like a poor peforming product, when it comes to the screen it has to at least be able to display the information given to it. In this case it can't.The only way to find out is to go and test the reference image on another iMac. Not something I am prepared to do any time soon. It would also be prudent to see how it performers on an mbp-r screen to see how it fairs.

Any photographer's are going to be very annoyed if they recieved a product that performers like that. It is just not supposed to be like that out of the box.

James_C · Dec 23, 2012

I did notice that you used a iMac in an Apple Store it is possible that someone messed with the calibration settings or perhaps someone in the store tried to compensate for the store lighting conditions, or perhaps it was just a bad sample.

The 27" iMac is still pretty new and is only just getting into people's hands. Here is a review extract I found on macnn :

Image quality is thankfully at least as good as before and, if anything, has become even better. Both sizes of iMac now use IPS (in-plane switching) LCDs instead of cheaper PVA (patterned vertical alignment) or TN (twisted nematic) panels found on most computer displays. Users of 24-inch iMacs will already know this experience well, but the end effect for the entire line is to get exceptionally rich colors and wide viewing angles. Brightness and absolute color accuracy does appear to drop off, but only at extreme perspectives that wouldn't be useful for work. In the right lighting environment, we'd seriously consider the iMac for color proofing in still image editing or a video production tool like Final Cut Studio's Color.

LED backlighting should make this even better, as it prevents the light from getting dim at the edges of the screen and ensures uniform color across the entire panel. To be honest, we'd never really noticed a vignetting effect on a 24-inch iMac, either. Even so, it does mean that the larger 27-inch panel won't risk that effect either. There's likewise the positive side-effect of lowered power consumption compared to a fluorescent display at the same size, not to mention fewer toxic chemicals to hurt the environment at the end of the computer's lifespan.

Maybe if you could post a link to the source image someone with a 27" iMac could download and test on their system and report back.

aznxscorpion517 · Dec 23, 2012

I have the new 27in iMac (late 2012) and I have this issue. It is quite annoying considering the work I do. I just jumped from an older MacBookPro, which had a matte screen and I enjoyed its amount of contrast very much as I was able to see all the detail in the shadows that I needed. I did Apple's built in calibration on the new iMac and it did not help much. I KNOW the detail is there but for some reason even doing the expert mode ColorSync cali does not help it along. I know the detail is there because if I used the Adobe RGB display profile that came with the iMac then it displays the exact amount of dynamic range or contrast I want. It's not all good though as it has a slight color cast. What I want is to be able to keep the dynamic range of the Adobe RGB profile but with the accurate colors of the custom profile I set up with ColorSync. That doesn't seem to be possible unless I'm missing something here. I've already gone to Accessibility and turned contrast enhance all the way down.

Anybody with any ideas? I'd rather not have to go hardware for something that seems silly and should be possible already since the Adobe RGB profile already does half of what I want.

Tri-stan · Dec 23, 2012

Can anybody report not having black crush on their new iMac's? Could you state weather or not it is a 27 inch. A photo of the screen would be useful showing the additional black detail.

You can download my reference image below thanks. "This is a RGB image color profile"
http://s133.beta.photobucket.com/user/tristanphoto_bucket/media/eBay/_DSC0103_zps727d3c42.jpg.html

aznxscorpion517 · Dec 23, 2012

Tri-stan said:
You can download my reference image below thanks.
http://s133.beta.photobucket.com/user/tristanphoto_bucket/media/eBay/_DSC0103_zps727d3c42.jpg.html

I downloaded your image and switching from the default "iMac" display profile with the "Adobe RGB" one I can see a difference in detail in the shadows. With "Adobe RGB" it looks as one expects and with "iMac" or whatever custom ones I made with ColorSync the shadows are a bit crushed. They don't seem as bad as your examples but it's still not very acceptable.

Do you experience better shadow detail when switching to "Adobe RGB" as well?

johto · Dec 23, 2012

I have imac 24" from 2008, and using my own calibrated display profile(hardware calibrated), your reference image showed up just fine without black crush inside preview and in photoshop (CS 5.1). Here is a screenshot with both photoshop & preview showing same image (preview is the smaller one). I made a screenshot and then saved it to RGB(converted to sRGB profile) for web so its should be close to what i see with my profile.

I think your problem is just that your imac default(wrong) profile is not good enough. Get an hardware calibrator and calibrate your monitor !

edit: i noticed that my posted image is "just a little" darker(in normal limits) than the reference image when viewing it inside the browser. I think this little "screw" is just normal because this image went through the following: your reference image, opened inside PS + preview -> screenshot -> opened again in PS and exported to web.

aznxscorpion517 · Dec 23, 2012

johto said:
I have imac 24" from 2008, and using my own calibrated display profile(hardware calibrated), your reference image showed up just fine without black crush inside preview and in photoshop (CS 5.1). Here is a screenshot with both photoshop & preview showing same image (preview is the smaller one). I made a screenshot and then saved it to RGB(converted to sRGB profile) for web so its should be close to what i see with my profile.

I think your problem is just that your imac default(wrong) profile is not good enough. Get an hardware calibrator and calibrate your monitor !

edit: i noticed that my posted image is "just" a little darker than the reference image when viewing it inside the browser. I think this little "screw" is just normal because this image went trough the following: your reference image, opened inside PS + preview -> screenshot -> opened again in PS and exported to web.

The OP's original reference image looks great with lots of shadow details. Your image that you posted from your monitor has crushed blacks if you ask what I see.

EDIT: Just read your edit though I don't know if it would really make that big a difference. Did it look like his ref image BEFORE you took a snapshot, etc?

johto · Dec 23, 2012

aznxscorpion517 said:
The OP's original reference image looks great with lots of shadow details. Your image that you posted from your monitor has crushed blacks if you ask what I see.

Ok good to know, so my black crush might be to do with the profile conversions inside the image path i just described..hmm

Anyhow, i DO see the the images just fine with great shadow details BEFORE i save the image to the web(see it inside browser) so my final web export might have something made wrong on my end...

edit: yeah, just checked it also on my PC, its the final save on my end that crushed it, on my end the screenshot shows good shadow details hmm..

I reuploaded the screenshot, hope i did not screwed again with the sRGB profiles too much:

Tri-stan · Dec 23, 2012

Right I think I have figured it out now, I have been using a RGB image on a sRGB imac

aznxscorpion517 said:
I downloaded your image and switching from the default "iMac" display profile with the "Adobe RGB" one I can see a difference in detail in the shadows. With "Adobe RGB" it looks as one expects and with "iMac" or whatever custom ones I made with ColorSync the shadows are a bit crushed. They don't seem as bad as your examples but it's still not very acceptable.

Do you experience better shadow detail when switching to "Adobe RGB" as well?

I don't know how the iMac color options work but I don't see any difference in shadow detail using my u2711 monitor. The monitor itself allows you to switch between adobe rgb presets and srgb so cycling through both of these I see no difference in shadow detail just a change in color reproduction. It depends on what color space has been set to produce colors for a given color space ie srgb.

In windows there are further setting to change what color profiles windows uses. I have mine set to display adobe rgb. In the past I have had this set to a default color space so srgb and all of my photos in the windows environment displayed poor saturation and especially a loss in black depth.

So currently because I am using a wide gamut color space I have my monitor set to adobe rgb and I have windows set to adobe rgb as well. I don't have the need for super color accurate images so the stock calibration from my dell monitor is enough.

The iMac has only a srgb capable panel so I can only recommend using its standard color setting srgb or a calibrated srgb setting. I have now found out now that the image that you downloaded was in rgb and this has been causing some problems and maybe the increased black crush. Although you have said that it has been present in other images you have been viewing. This is also true for the iMac which I tested the image on in store. Although there may still be some black crush present using a srgb image*

Here below is the correct image in adobe srgb and download link:

http://s133.beta.photobucket.com/us...umors/ReferenceImagesRGB_zpsbf645ba5.jpg.html

torana355 · Dec 23, 2012

Calibrate your monitor if you need accurate blacks and colour. I even had to get my top of the line Panasonic plasma professionally isf calibrated.

blueroom · Dec 23, 2012

Try using Xee to view the photos, you can try RGB or YUV etc.

PS the S3 camera took the third photo off the Apple screen, what took the photo on the PC screen (is it a screen cap?). Your S3 camera is a pretty poor reference.

Tri-stan · Dec 23, 2012

johto said:
Ok good to know, so my black crush might be to do with the profile conversions inside the image path i just described..hmm Anyhow, i DO see the the images just fine with great shadow details BEFORE i save the image to the web(see it inside browser) so my final web export might have something made wrong on my end...

edit: yeah, just checked it also on my PC, its the final save on my end that crushed it, on my end the screenshot shows good shadow details hmm..

I reuploaded the screenshot, hope i did not screwed again with the sRGB profiles too much:

How were you able to get the iMac to display the rgb image? I see now that the iMac will work fine with srgb images but you have to change some settings inside OSX to display rgb right? It would be good to test this on a 2012 iMac thought.

So this whole time the problem was that I was using a rgb image on a srgb capable iMac? Although another user was experiencing some black crush on a 27 inch iMac so it may not be fully resolved but using the correct image makes a big difference. Good to see the quality of the image now on your machine

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