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iMac 5K and judging sharpness

Posted: Wed May 05, 2021 6:18 pm
by Scott A. Flaherty
I finally got around to upgrading my aging iMac. I now have an iMac 5K 27". Works great. That is until I started to prepare some images for printing. I'm having the hardest time judging the sharpness of my images on a display with resolution this high. Is anyone else experiencing this?

Re: iMac 5K and judging sharpness

Posted: Thu May 06, 2021 7:25 pm
by bradmangas
Hi Scott, I have mentioned this before but not real sure folks understand all that is going on when it comes to 4k and now 5k displays. This issue happens to a lesser degree when on a pc, but when a 4k or higher resolution display is attached to a Mac there are inherent issues that take place specifically when sharpening images for print.

I will try to put this in a nutshell so to speak, since it can get very in-depth. When viewing an image on a 4k or 5k display on a Mac you are not actually viewing an accurate representation of the image on your screen. It is a lower resolution image that is being emulated by software to show for the 5k display. Obviously this is done to be able to use the full 5k potential of the display.

This is not a problem for 99% of users or if  you do not require critical accuracy in detail. But when a person is attempting to do detail critical work and evaluation, such as image sharpening for a fine art print, it is a tremendous problem. Basically what you are seeing on your 5k display is not an accurate representation of what is inherent in the image file. In the case on a Mac, Apple is adding "possibly" edge contrast or some form of sharpening to the (non-5k) image to make it look better on the screen when it (for lack of a better word) "stretches" it out for something like a 5k display. This does make it look better on the screen, but screws everything up when you want to print the image.

I don't what to complicate this anymore than necessary and I will try to be of help. First, your only option is lots of trial and error with each print you make if you chose to use only a 5k display. This may not be a problem if you don't do much printing. If by chance you do or plan to do a good amount of printing, the more practical option is to not use a 5k display and replace it with a quality color calibratable monitor. Something in the neighborhood of 2560 by xxxx native resolution.

Bottom line is anyone attempting to do detail critical work, especially when it comes to sharpening an image properly for print will struggle on a Mac when using a 4k or higher resolution monitor.  It's just the nature of the beast.

Posted: Fri May 07, 2021 8:56 am
by Scott A. Flaherty
Does anyone have some suggestions for a 27" (2560 x 1440) display for under $700, that would still be good for photo processing? I think I would really just need it for critical sharpness evaluation. I was going to get a second display anyway, but now I'll need it for a more specific purpose.

Re: iMac 5K and judging sharpness

Posted: Fri May 07, 2021 9:31 pm
by bradmangas
A second monitor is a good idea. I honestly can not provide much in the way of monitor advice since I have not been in the market for one for some time. I have been using an NEC monitor with the Spectraview II hardware and software calibration system for some years now and it still preforms great. As far as something to look at for a good second monitor, I have hear good things about the BenQ series of monitors. They may be your best option for something in that price range.

Something that looks good spec wise but is slighter higher than $700 at $799 would be the:

27 inch Photo Editing Monitor, 2K Adobe RGB | SW270C https://www.benq.com/en-us/monitor/phot ... w270c.html

Posted: Sat May 08, 2021 12:20 pm
by Scott A. Flaherty
Thanks Brad. That BenQ looks interesting.

Posted: Tue May 11, 2021 5:59 am
by E.J. Peiker
The BenQ is the best option in your general price range.