Comparing monitor to print resolution (iMac)

<p>I am thinking of acquiring an Apple iMac 21.5 inch which has a monitor providing approximately 9.5 MP (4096 by 2304 pixels) over a roughly 11.4 x 18.1 inch surface (Retina display). If my math is correct, this would give me about 220 ppi which would be similar to a 215 dpi print. Often I print at resolutions between 150 and 300 dpi so the monitor should be quite accurate as a predictor of print resolution</p>

<p>The 21.5 inch Apple is quite a bit cheaper than the 27 inch and while it has a different graphics card (not sure how the Intel Iris Pro Graphics 6200 compares to the AMD Radeon R9 M380, R9 M390, R9 M395 or R9 M395X graphics processors of the 27 inch models), differing upgradeable memory limits (16 GB versus 32 GB) and slightly differing processor speeds, the monitor of the 27 inch (5120 x 2880 pixels or 17.75 MP)) has approximately the same resolution (circa 220 ppi) as the 21.5 inch computer.</p>

<p>My tired iMac 24inch has a resolution of about 95 dpi. A resolution difference of 220 over 95 seems meaningful in terms of judging print quality from a purely resolution viewpoint.</p>

<p>There seems to be no advantage of a 27 inch over a 21.5 inch monitor apart from a larger image, as the ppi or dpi are similar between the two. What do those of you using Apple computers think? Would I be missing something important for photography usage by not acquiring a 27 inch iMac ? The difference in price in my area varies from 20% more to about 55% more based largely on the graphics processor (With the 27 inch each AMD Radeon R9 processor has a 2GB video memory, but that is probably unimportant for still photography).</p>

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<p>21.5 inch is rather small, I think. I think you would very much prefer a 27 inch. You will also find normal text and desktop icons rather small on a 4K screen, so you need to be prepared for this. I don't think the Apple screens are wide gamut, if this is important to you.</p>

<p>Screen resolution is probably not significant as long as it is greater than the that of your eye at normal viewing distance. With a screen, you can always magnify the image to the pixel level (or greater) to examine details. That's hard to do with a print unless you use a magnifier. Even then, you resolve dots, not the image.</p>

<p>27" (diagonal) is a reasonable size for a monitor. Any larger and you can't see the entire screen without scanning with your eye, and the illumination may not be consistent across the width. I have a 22" display at present, but larger would be nicer since much of the display is taken up by controls in various editing programs. In other words, practical issues are more important than "seeing" the results of your work on the large screen.</p>

<p>Text size can usually be specified to a certain default level. Some applications are non-compliant in this regard. </p>

<p>Last fall I replaced my ancient 24" iMac with the 27 " model, and I would certainly recommend the 27 over the 21.5 model. The 21.5 can only accommodate 16 gigs of RAM while the 27 can take 32 gigs, and I think that only the 27 allows you to upgrade that yourself, while the 21.5 must be ordered with either 8 or 16 gigs from the factory. Third party RAM is much cheaper and just as good in my experience. As for the resolution difference, it is substantial, and I have really enjoyed being able to see a lot more of the image on the screen at 100% for retouching, etc., as well as having somewhere for the palettes to go on the larger screen. Something else that I specified is the combo drive that has SSD for part of the drive for start up and software. My new 27" starts up much faster and launches Photoshop and other programs 4 or 5 times as fast as my old machine.</p>

<p>I like a 27" inch display (or larger) for working with stills and video, and a second display for tools/housekeeping running next to it. 21" is too small, for sure. </p>

<p>I'm not sure if "predicting print resolution" has much practical value, unless your main goal is to figure out how big you can print a given comparably small file for a certain viewing distance. - But still: Does the fixed resolution of the monitor really help there, when everybody would just change the lpi / screen dot size which can't be done on a flat computer monitor, while it was an option on CRTs which unfortunately didn't provide as much resolution as the modern flat screens. - A Retina display might be great, if you need to do layout around ancient low res captures (1.5MP P&S images, photo CDs and similar) though.<br>

I have a 27" 4K screen for my PC and adored the 27" Retina iMac too, but I see the main value of those screens as a print substitute; i.e. a means to enjoy images without having to print them at all.<br>

To do work on pixel level they feel "wrong" to me. - I'd prefer a conventional 24" screen for such, since it lets me see what I am doing. - Given a chance to choose, I'd try to get the bigger Retina iMac, mainly as a digital picture frame, not really for working on it, besides weeding out the results of a spray & pray approach.</p>

<p>Thanks for all comments and suggestions to date. The better graphic cards are of little use to me so I can save quite a bit of money there in going for the basic or middle 27 inch models. I appreciate the reasons for the 27 inch rather than 21.5 inch Retina models, notwithstanding their similar resolution in pixels per inch. The purchase upon ordering of an SSD drive together with the standard hard drive, or upgrading the Fusion drive's flash drive from the current less than 30 MB to 128 MB SSD is also worthwhile.</p>

<p>Robin, to answer your question, I believe that the gamut of the new iMacs is improved, with 130% of rRGB gamut being achieved and also 99% of the DCI-P3 color spec being attained. Uniformity across the screen, color temperature and viewing angle limitations are things I am not yet sure about, but apparently the screen is less glossy on these new models than former ones. </p>

<p>Thanks Arthur. Good to know.</p>

<p>Arthur, go with the 27in. It's the biggest and just the right size you'll ever need or want for photo editing.</p>

<p>If I went with a larger display than my 27in. I'ld end up seeing distortions from looking at far left and right edges because I'm too close to the display. If I'm going to have to view from farther back I might as well get a 4K HDtv and edit from my couch.</p>

<p>Arthur: Have you considered using a color auto-calibratable unit like the one I use from NEC? (PA242W with Spectraview II "puck") They also make a 27". The 21" that I use seems large enough for me but 27" would be nice too. Maybe you can try them both out at a store. Good luck with whatever you decide.</p>

<p>Tim, I will likely go for the 27inch, thanks to your and other advice here, and from reading reviews. Alan, I once thought of the NEC PA242W and equivalent Eizo monitors that are highly respected but a bit outside my present budget. I already have a Colormunki calibrator that may be useful to further calibrate the MAC. The Apple monitor may not be as fine as those of NEC and Eizo, but the Apple 5K screen is something that can be had in professional quality monitors although its price combined with the computer is about the same, making the new iMAC somewhat of a bargain.</p>