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M.Chapman

27" iMac Retina display resolution problem - is it just me?

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Posted (edited)

I'm running Mojave and the latest PS CC (21.2) on a 27" iMac with Retina Display. I expected images in PS to appear about 1/2 size (linear dimensions) on the iMac than they did on my previous non-retina system, because the pixels are half as big. But I'm seeing images that are 1/4 of the size. I'm trying to find out if it's just me (due to a setting gone wrong somewhere during the migration process) or if there's a bug. Is there anyone here with a 27" iMac with a retina display who can try a simple test? 

 

Set the Display resolution in Apple System settings to 2,560 x 1,440 (the default)

Open Photoshop in normal mode (not low res) and create a 1,000 x 1,000 image

Measure the width of the image in cm when viewed in the PS edit window at 100%

 

The 1,000 x 1,000 image I see on screen is only 11.5cm across on a screen that is 59.5cm wide.

11.5/59.5 x 2,560 = approx 500 pixels (instead of 1,000)

 

At first I thought this must be because the true display resolution of the 27" iMac is  5,180 x 2,880 and PS is simply not respecting the scaling set in Apple System Display settings. So I changed the setting and proved the PS is taking this setting into account. For example, if I change the display to 1,600 x 900, the size of my 1,000 x 1,000 image increases to 18.5cm.

18.5/59.5 x 1,600  = approx 500 pixels (instead of 1,000).

 

Whatever setting I choose, the image is 1/2 the size (linear dims) it should be. The only way around it is to start PS in "low res mode", but that makes things "fuzzy".

 

Mark

Edited by M.Chapman

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Posted (edited)

Resizing an image to 1000 pixels width creates an image 11.5 cm across at 100% ( measured with a ruler).

Edited by geogphotos

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Posted (edited)
1 hour ago, geogphotos said:

Resizing an image to 1000 pixels width creates an image 11.5 cm across at 100% ( measured with a ruler).

 

Excellent, thanks. So it's not just me, you're seeing the same.

 

So, to inspect images at the same effective magnification I was using on my previous (non-retina) display in PS at 100% when using new 27" iMac 5,120 x 2,880 display, I have to set Apple display scaling to 2,560 x 1,440 and also view at 200% in Photoshop. It shouldn't be necessary to do both of these (which in theory should apply a factor of 4x magnification when only 2x is needed to handle the smaller pixels in the retina display), there's clearly a bug somewhere.

 

I've been on the Adobe forum about this, but they just think I'm an idiot. :wacko:

 

Mark  

Edited by M.Chapman

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Posted (edited)

I just view at 100% on most occasions although am aware that it isn't really 100%. Sometimes I need to view at 200% when doing old scans to pick up all the dust spots.

 

All I know is that I am getting QC passes for these images and also for digital images of dark church interiors at high ISO which can look a little dubious at 100%.

 

I hope that making this post isn't going to be the equivalent of 'commentator's curse'. 😁

Edited by geogphotos
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Posted (edited)

I think I understand what you mean, and I have noticed this as well. My guess is that PS is trying to be smart because most people will run in the default resolution on Apple's retina displays which is pixel doubled @ 2,560 x 1,440 (otherwise, if you ran at native res everything would be so small you couldn't read it) and so even in this default "pixel doubled" res PS is attempting to display everything as if you were running at the native res. I noticed this pretty soon after starting to use PS that I was having to zoom up to 200% to see the same size output that I'd see for instance in the preview app had I clicked the option in the view menu "actual size".

 

It's also worth noting though, and I guess you may already know this, that the way most applications are behaving in the pixel doubled res isn't actually showing you images at 100% when you view them in "actual size" but at 200%. It took me a while to work out why virtually no image I look at fully zoomed actually looks pin sharp, because it is in fact being blown up to 200%. So in this sense PS is working correctly. Don't forget, the native res of the 27" iMac means that if you open an image that is 5000px long (so around 20MP?) and go fullscreen, you don't even have to zoom the image as it is already technically being viewed at full size 100%.

 

I might be mistaken, but I think LR works this way as well. Certainly when I look at an image in LR at 1:1, it is not as "blown up" as it is in preview when I click view "actual size". If the adobe apps didn't work this way, then technically they would be deceiving the person working on the image by making them think that what they were seeing at 200% was actually the 100% view. Given how small everything looks on a hiDPI screen when you run it in native res, it is unreasonable to expect people to switch to a native res so this seems like the only compromise.

Edited by Cal
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Posted (edited)

I am not intending to invest too much brain power on this but I think you are obsessing unnecessarily and banging your head on a wall that is not going to change for you. As Cal (I think) and the guys on the Adobe Forum definitely have explained, the behaviour you are observing is correct and as it is meant to be. You can bang your head on a wall here but you are not going to change anything no more than you are going to get Alamy to change their (lack of colour) management policy.

 

The statement " I have to set Apple display scaling to 2,560 x 1,440 and also view at 200% in Photoshop." doesn't make any sense to me. You should see the same amount of an image on screen viewing an image at 100% on a 2560 27" monitor as at 200% on a 5K 27" monitor. To judge noise and sharpness properly you need to view at 200% on a 5K although subjectively I think it is better to view at 100% on a 2560 monitor. I recall having this conversation some years ago in fact.

 

In my opinion you can't beat the sweetspot of a 27" 2560 x 1440 wide gamut monitor that allows for proper calibration for photo processing. That BenQ is still there with no name on it yet by the way 😀.

Edited by MDM

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17 minutes ago, MDM said:

The statement " I have to set Apple display scaling to 2,560 x 1,440 and also view at 200% in Photoshop." doesn't make any sense to me.

 

Well to be fair that's not the whole statement. Self contained the above doesn't make much sense, but in the wider context of what he said it does.

 

The nuances of hiDPI monitors do take some getting your head round. It's quite a departure from the LCD monitors of yesteryear where resolution more or less went hand in hand with the physical size of the thing.

 

I would mostly agree with what you said here: "To judge noise and sharpness properly you need to view at 200% on a 5K although subjectively I think it is better to view at 100% on a 2560 monitor" though that does somewhat depend on the size of said 5K monitor and its distance from your face. On the iMac, yes I would definitely agree, and I often switch to 2:1 in LR for instance to briefly check clarity. But for a massive 5K TV you might be less inclined to do this.

 

I think it definitely helps to have a monitor that is so sharp and crisp, and I am consistently reminded of this fact when I shift over to my work PC with a godawful (by comparison) 1080p monitor which is honestly like looking through the bottom of a milk bottle in comparison.

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Posted (edited)
15 minutes ago, Cal said:

 

Well to be fair that's not the whole statement. Self contained the above doesn't make much sense, but in the wider context of what he said it does.

 

The nuances of hiDPI monitors do take some getting your head round. It's quite a departure from the LCD monitors of yesteryear where resolution more or less went hand in hand with the physical size of the thing.

 

I would mostly agree with what you said here: "To judge noise and sharpness properly you need to view at 200% on a 5K although subjectively I think it is better to view at 100% on a 2560 monitor" though that does somewhat depend on the size of said 5K monitor and its distance from your face. On the iMac, yes I would definitely agree, and I often switch to 2:1 in LR for instance to briefly check clarity. But for a massive 5K TV you might be less inclined to do this.

 

I think it definitely helps to have a monitor that is so sharp and crisp, and I am consistently reminded of this fact when I shift over to my work PC with a godawful (by comparison) 1080p monitor which is honestly like looking through the bottom of a milk bottle in comparison.

 

What I meant was that it should not be necessary to set the scaling to 2560 and view at 200%. One of those should be enough. The size of the monitor is important as you mention which is why I specified 27". Some years ago I invested in a 27" wide gamut matte Eizo monitor and that was really worth it as I can judge the sharpness and see a pretty wide gamut of colour as well as great tonal range. My previous Mac 21" monitor looked good when I bought it but only realised what I was missing when I got the Eizo - I was able to see detail in highlights (in particular) and shadows that my cameras and Lightroom were capturing and making visible but unable to see on the monitor I previously had. 

 

As for crappy monitors, why spend fortunes on camera gear and lenses and then view the images on a crappy monitor - that does not make sense to me. Most people don't even print any more so the only way they ever see their images is on screen.

 

The only real problem with the Retina monitors is they tend to conceal the flaws - it is much harder to see noise and next to impossible to tell sharpness at 100% at native resolution - and they to be too contrasty which is not adjustable. But they do make for good-looking images although the images might not look so good on another device or  printed without special care. Fortunately the workarounds are easy to do. That is why I think Mark is over-obsessing here.

 

 

Edited by MDM

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12 minutes ago, MDM said:

 

What I meant was that it should not be necessary to set the scaling to 2560 and view at 200%. One of those should be enough.

 

 

 

It depends what you're trying to achieve. He said "So, to inspect images at the same effective magnification I was using on my previous (non-retina) display in PS at 100% when using new 27" iMac 5,120 x 2,880 display, I have to set Apple display scaling to 2,560 x 1,440 and also view at 200% in Photoshop". He is actually right about that, as PS (and LR) behave at odds with other software when in the standard 2560x1440 res mode. PS and LR will act as if the system is running at native res, not in its pixel doubled res. I get why they do this, and I've explained why already but his point is that he has to view at 200% to get the same dimension image the system should give him naturally with the res already being pixel doubled. Regardless of the logic behind it or whether you think it's right or wrong (or productive) he still has a point.

 

15 minutes ago, MDM said:

As for crappy monitors, why spend fortunes on camera gear and lenses and then view the images on a crappy monitor - that does not make sense to me. Most people don't even print any more so the only way they ever see their images is on screen.

 

 

I don't know if this is related to my 1080p monitor comment but my "work" is nothing graphics related and my employer pays for the equipment so I takes what I get given.

 

16 minutes ago, MDM said:

The only real problem with the Retina monitors is they tend to conceal the flaws - it is much harder to see noise and next to impossible to tell sharpness at 100% at native resolution - and they to be too contrasty which is not adjustable. But they do make for good-looking images although the images might not look so good on another device or  printed without special care. Fortunately the workarounds are easy to do. That is why I think Mark is over-obsessing here.

 

I have mixed opinions over this.

 

I don't think they necessarily conceal flaws at all. In fact, when I got my iMac it made me realise how poor a lot of my images up until that point were. It's very easy when working on a monitor that doesn't fall into the hiDPI category to completely miss finer details like slight misfocus or noise, even at 100% if the aberration is only very slight. This was the first thing I noticed when I got the iMac, is how substandard a lot of what I'd done up to that point was.

 

I wouldn't say Mark is over obsessing; he's discovered an interesting nuance and is discussing it. I would personally like Mac OS to behave system wide like PS and LR do - run pixel doubled but when viewing an image at 100% do so according to the actual pixel count of the screen, not blowing up the image to double size because of the pixel doubled res.

 

To be honest I've bored myself now, so I'll away and enjoy my evening while others pass comment...

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Posted (edited)

I  was very wary about entering this thread anyway. I have been around the forum for quite some time now and know Mark pretty well so feel I can call a spade a spade with him without it being interpreted as an insult (I hope). Perhaps I am gently teasing him as we know each other quite well although we have not yet met in person. I like Mark and am in awe of his brain power at times but he has a tendency to delve very deeply into things and sometimes find flaws. However, they are sometimes flaws that there is no chance of fixing so can be a waste of time if that is the case as with his investigation of Alamy's colour management policy.

 

In this case, it is definitely going to be a frustrating time as Apple and Adobe are most unlikely to change things. In situations like this, my philosophy is to find a workaround and not worry about it too much. This works for me. I consider myself to be a pragmatic perfectionist. I aim high but if I hit an immovable infinite wall then I give up. 

 

As for Retina or other High Res screens, relative to a really high quality matte monitor, it definitely can be harder to see detail and noise at native resolution. A reflective screen is not helpful in this regard either. 

Edited by MDM

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1 hour ago, MDM said:

That BenQ is still there with no name on it yet by the way 😀.

 

Sorry to deviate from this threads title. Michael, if you are Peterborough based, can I contact via txt or phone for info on the display?

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5 minutes ago, sb photos said:

 

Sorry to deviate from this threads title. Michael, if you are Peterborough based, can I contact via txt or phone for info on the display?

 

Yes sure. I just emailed you as you Facetimed me but it cut out before I got to the phone. I will email you my number now.

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Posted (edited)

Interesting disparity of views 😀. I'm just stating the observations that I've arrived at through testing and discussion on the Adobe forum. To view images at exactly the same size on a 27 inch 2,560 x 1,440 standard resolution monitor and on a iMac 27 inch 5,120 x 2,880 Retina display in Mojave (and possibly other Mac OS versions) it's necessary to check that Apple System Display preferences are set to a resolution of 2,560 x 1,440  and to view the image at 200% in PS on the iMac. I post this here because, to me, that's somewhat counter-intuitive. I originally thought it must be a bug, but it seems the behaviour is deliberate (eee * below).

 

Once this is done I can inspect images on an iMac with an equal level of "100%" scrutiny, as required by Alamy, because my eyes can just resolve the individual image pixels on both displays, and there's no problem using the iMac display. Indeed I find it to be an excellent display with no contrast problems, it calibrates just fine. I also really like the flat AR coated glass which gives a clearer view of the image than my previous matt finish monitor. No problems seeing image noise or details, at 200% 🙂, or with screen reflections in my work area. Although I must say I'm suitably underwhelmed by the difference between correctly rendered versions of real world saturated landscape sRGB and AdobeRGB images which I can now see on the P3 Gamut iMac display. I'd say it's more important to have a calibrated sRGB display than an uncalibrated wide gamut display in terms of ensuring image quality. As a result I'll continue to work in sRGB for Alamy and the other libraries I contribute to, and for my own image library.

 

*There's a useful post on how Adobe PS and Apple's display settings interact here. See the answer from Pete Green (Adobe Employee).

There is another way to achieve the same size image which is to open PS in Low Res Mode (right click on File Info setting for the App) and view at 100%, but the end result is less sharp.

 

Banging my head against a brick wall as nothing will change... I wondered why I had a headache.... 😀

 

I was initially concerned that by simply migrating my apps and settings (including PS CC) from a non-retina system onto a retina system that some system settings/preferences might be incorrect, and then I could easily fix them. Failing that I could raise a bug report if there was an identified problem. But I'm now happy I understand what's going on and I can inspect my images with confidence. (Oh the headache has gone... 😀 )

 

Thanks for the reminder about your Benq display. As you've probably deduced I've gone with a 27" iMac (I got a nearly new one S/H on Tuesday) as it addressed all three of my requirements in one hit (upgrade to larger monitor, ability to work in wide gamut if needed, and more processing power). So the Benq is no longer an option.

 

Mark

 

Edited by M.Chapman

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Posted (edited)
5 hours ago, MDM said:

The statement " I have to set Apple display scaling to 2,560 x 1,440 and also view at 200% in Photoshop." doesn't make any sense to me. You should see the same amount of an image on screen viewing an image at 100% on a 2560 27" monitor as at 200% on a 5K 27" monitor.
 

What I meant was that it should not be necessary to set the scaling to 2560 and view at 200%. One of those should be enough. 

 

Yes, that's exactly what I thought, but it turns out to be wrong when viewing in PS on an iMac Retina display. You have to set 200% and set 2,560 x 1,440 (which is the default setting).  Strange world... :wacko:  I think the same is true in LR,  I'll double-check and post the result.

 

Mark

 

Update: I can confirm that LR CC, PS CC (and ACR), Affinity Photo and Capture One all perform the same way. i.e. images need to be viewed at 200% / 2:1 with Display Resolution set to 2,560 x 1,440 on iMac with 27" Retina display. This will give the same size rendering as viewing the same image at 100% / 1:1 on a 27" 2,560 x 1,440 non-retina display.

Edited by M.Chapman

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2 hours ago, M.Chapman said:

 

Yes, that's exactly what I thought, but it turns out to be wrong when viewing in PS on an iMac Retina display. You have to set 200% and set 2,560 x 1,440 (which is the default setting).  Strange world... :wacko:  I think the same is true in LR,  I'll double-check and post the result.

 

Mark

 

Update: I can confirm that LR CC, PS CC (and ACR), Affinity Photo and Capture One all perform the same way. i.e. images need to be viewed at 200% / 2:1 with Display Resolution set to 2,560 x 1,440 on iMac with 27" Retina display. This will give the same size rendering as viewing the same image at 100% / 1:1 on a 27" 2,560 x 1,440 non-retina display.


OK but that does not make sense to me at all. As long as you can properly judge sharpness and see any noise at native resolution at 200% if necessary  then it is not really a big deal I guess or maybe I am not understanding. 

 

2 hours ago, M.Chapman said:


Although I must say I'm suitably underwhelmed by the difference between correctly rendered versions of real world saturated landscape sRGB and AdobeRGB images which I can now see on the P3 Gamut iMac display. I'd say it's more important to have a calibrated sRGB display than an uncalibrated wide gamut display in terms of ensuring image quality. As a result I'll continue to work in sRGB for Alamy and the other libraries I contribute to, and for my own image library.

 

 

 

 

Yes but I would still go for a wide gamut properly calibrated monitor. Apple are trying to be all things to all men (and women) with their iMac monitors but I think they are limited compared to a monitor designed for photographic post-processing. Unless you have discovered something I missed, it is not possible to change the contrast on a Retina iMac screen and they are a bit too contrasty for my liking. This will only really become evident if you try to print in a colour managed workflow. What looks contrasty on screen might look much flatter in a print.
 

Having an iMac does not preclude having another wide gamut monitor by the way. A nice two monitor setup is hard to beat 😎


 

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Posted (edited)
19 minutes ago, MDM said:

Unless you have discovered something I missed, it is not possible to change the contrast on a Retina iMac screen and they are a bit too contrasty for my liking.

 

The screen calibration tools I have allow the contrast to be adjusted if needed, although I must admit I leave the target contrast range as native as I'm not producing prints.

 

19 minutes ago, MDM said:

OK but that does not make sense to me at all.

 

You and me both. But that's the way it is. It seems that PS have decided that when it comes to the image display, the native resolution (physical pixels) of the monitor is what they will use to determine what constitutes 100% rendering of the image. i.e. 1 image pixel is shown using 1 physical display pixel. The "artificial" 200% pixel doubling that Apple apply to Retina displays is ignored by PS, apart from when they draw the user interface elements (menus etc.). The Adobe forum post I mentioned by Pete Green here gives some insight into what's going on behind the scenes.

 

The key thing is it's not a bug and I have a simple workaround (view at 200%)

 

Two monitors :lol::lol:

 

Mark

Edited by M.Chapman

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1 hour ago, M.Chapman said:

 

 

You and me both. But that's the way it is. It seems that PS have decided that when it comes to the image display, the native resolution (physical pixels) of the monitor is what they will use to determine what constitutes 100% rendering of the image. i.e. 1 image pixel is shown using 1 physical display pixel. The "artificial" 200% pixel doubling that Apple apply to Retina displays is ignored by PS, apart from when they draw the user interface elements (menus etc.). The Adobe forum post I mentioned by Pete Green here gives some insight into what's going on behind the scenes.

 

 

In fairness though as I alluded to above (but I tend to not be very good at explaining myself) this is the approach that IMO actually makes sense. What doesn't make sense is that the Mac App "preview" will show an image at 200% zoom when you click the option in view -> "actual size". It isn't the actual size, what PS is doing is, and for reviewing the image at a pixel level it's important to know you're getting accurate information.

 

Unfortunately because of the way hiDPI monitors (without some resolution fudging) would naturally tend to display screen elements in an absolute miniscule fashion owing to their huge pixel count, I think this is the best compromise. At least until we are 20 years in the future and everything is designed from the ground up to take advantage of the colossal pixel counts, instead of now where everything is still designed to be backwards compatible with grandma's 1024x768 LCD from 2002. To put it into perspective, the Apple logo in the Apple menu is 32 pixels high and it is tiny. Yet that is the same size as the standard sized desktop icons on Windows computers up to XP - yes, those large desktop icons that used to so easily fill the screen. The thing that'll really burn your bacon is, I screenshotted the Apple logo to measure its pixel count for this post (to make sure I wasn't going bananas). When I open it in preview, it appears twice the size due to pixel doubling! When I open it in Photoshop it appears in the original (correct!) size, the same as the actual logo in the top bar. So we can agree I think that the Adobe Apps behaviour is at least the most logical!

 

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1 hour ago, M.Chapman said:

 

The screen calibration tools I have allow the contrast to be adjusted if needed, although I must admit I leave the target contrast range as native as I'm not producing prints.

 

 

You and me both. But that's the way it is. It seems that PS have decided that when it comes to the image display, the native resolution (physical pixels) of the monitor is what they will use to determine what constitutes 100% rendering of the image. i.e. 1 image pixel is shown using 1 physical display pixel. The "artificial" 200% pixel doubling that Apple apply to Retina displays is ignored by PS, apart from when they draw the user interface elements (menus etc.). The Adobe forum post I mentioned by Pete Green here gives some insight into what's going on behind the scenes.

 

The key thing is it's not a bug and I have a simple workaround (view at 200%)

 

Two monitors :lol::lol:

 

Mark


I am not going to think about this any more as it is not currently relevant to me. I have been using two monitors in one form or other for a long time and highly recommend it for comfort and productivity. Sweet dreams people. 

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